/* * $Id$ * PortAudio Portable Real-Time Audio Library * Latest Version at: http://www.portaudio.com * ALSA implementation by Joshua Haberman and Arve Knudsen * * Copyright (c) 2002 Joshua Haberman * Copyright (c) 2005 Arve Knudsen * * Based on the Open Source API proposed by Ross Bencina * Copyright (c) 1999-2002 Ross Bencina, Phil Burk * * Permission is hereby granted, free of charge, to any person obtaining * a copy of this software and associated documentation files * (the "Software"), to deal in the Software without restriction, * including without limitation the rights to use, copy, modify, merge, * publish, distribute, sublicense, and/or sell copies of the Software, * and to permit persons to whom the Software is furnished to do so, * subject to the following conditions: * * The above copyright notice and this permission notice shall be * included in all copies or substantial portions of the Software. * * Any person wishing to distribute modifications to the Software is * requested to send the modifications to the original developer so that * they can be incorporated into the canonical version. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ #define ALSA_PCM_NEW_HW_PARAMS_API #define ALSA_PCM_NEW_SW_PARAMS_API #include #undef ALSA_PCM_NEW_HW_PARAMS_API #undef ALSA_PCM_NEW_SW_PARAMS_API #include #include /* strlen() */ #include #include #include #include #include #include #include /* For sig_atomic_t */ #include "portaudio.h" #include "pa_util.h" #include "../pa_unix/pa_unix_util.h" #include "pa_allocation.h" #include "pa_hostapi.h" #include "pa_stream.h" #include "pa_cpuload.h" #include "pa_process.h" #include "pa_linux_alsa.h" /* Check return value of ALSA function, and map it to PaError */ #define ENSURE_(expr, code) \ do { \ if( UNLIKELY( (aErr_ = (expr)) < 0 ) ) \ { \ /* PaUtil_SetLastHostErrorInfo should only be used in the main thread */ \ if( (code) == paUnanticipatedHostError && pthread_self() != callbackThread_ ) \ { \ PaUtil_SetLastHostErrorInfo( paALSA, aErr_, snd_strerror( aErr_ ) ); \ } \ PaUtil_DebugPrint( "Expression '" #expr "' failed in '" __FILE__ "', line: " STRINGIZE( __LINE__ ) "\n" ); \ if( (code) == paUnanticipatedHostError ) \ PA_DEBUG(( "Host error description: %s\n", snd_strerror( aErr_ ) )); \ result = (code); \ goto error; \ } \ } while( 0 ); #define ENSURE_SYSTEM_(expr, success) \ do { \ if( UNLIKELY( (aErr_ = (expr)) != success ) ) \ { \ /* PaUtil_SetLastHostErrorInfo should only be used in the main thread */ \ if( pthread_self() != callbackThread_ ) \ { \ PaUtil_SetLastHostErrorInfo( paALSA, aErr_, strerror( aErr_ ) ); \ } \ PaUtil_DebugPrint( "Expression '" #expr "' failed in '" __FILE__ "', line: " STRINGIZE( __LINE__ ) "\n" ); \ result = paUnanticipatedHostError; \ goto error; \ } \ } while( 0 ); #define ASSERT_CALL_(expr, success) \ aErr_ = (expr); \ assert( success == aErr_ ); static int aErr_; /* Used with ENSURE_ */ static pthread_t callbackThread_; typedef enum { StreamDirection_In, StreamDirection_Out } StreamDirection; /* Threading utility struct */ typedef struct PaAlsaThreading { pthread_t watchdogThread; pthread_t callbackThread; int watchdogRunning; int rtSched; int rtPrio; int useWatchdog; unsigned long throttledSleepTime; volatile PaTime callbackTime; volatile PaTime callbackCpuTime; PaUtilCpuLoadMeasurer *cpuLoadMeasurer; } PaAlsaThreading; typedef struct { PaSampleFormat hostSampleFormat; unsigned long framesPerBuffer; int numUserChannels, numHostChannels; int userInterleaved, hostInterleaved; snd_pcm_t *pcm; snd_pcm_uframes_t bufferSize; snd_pcm_format_t nativeFormat; unsigned int nfds; int ready; /* Marked ready from poll */ void **userBuffers; snd_pcm_uframes_t offset; StreamDirection streamDir; snd_pcm_channel_area_t *channelAreas; /* Needed for channel adaption */ } PaAlsaStreamComponent; /* Implementation specific stream structure */ typedef struct PaAlsaStream { PaUtilStreamRepresentation streamRepresentation; PaUtilCpuLoadMeasurer cpuLoadMeasurer; PaUtilBufferProcessor bufferProcessor; PaAlsaThreading threading; unsigned long framesPerUserBuffer, maxFramesPerHostBuffer; int primeBuffers; int callbackMode; /* bool: are we running in callback mode? */ int pcmsSynced; /* Have we successfully synced pcms */ /* the callback thread uses these to poll the sound device(s), waiting * for data to be ready/available */ struct pollfd* pfds; int pollTimeout; /* Used in communication between threads */ volatile sig_atomic_t callback_finished; /* bool: are we in the "callback finished" state? */ volatile sig_atomic_t callbackAbort; /* Drop frames? */ volatile sig_atomic_t callbackStop; /* Signal a stop */ volatile sig_atomic_t isActive; /* Is stream in active state? (Between StartStream and StopStream || !paContinue) */ pthread_mutex_t stateMtx; /* Used to synchronize access to stream state */ pthread_mutex_t startMtx; /* Used to synchronize stream start in callback mode */ pthread_cond_t startCond; /* Wait untill audio is started in callback thread */ int neverDropInput; PaTime underrun; PaTime overrun; PaAlsaStreamComponent capture, playback; } PaAlsaStream; /* PaAlsaHostApiRepresentation - host api datastructure specific to this implementation */ typedef struct PaAlsaHostApiRepresentation { PaUtilHostApiRepresentation commonHostApiRep; PaUtilStreamInterface callbackStreamInterface; PaUtilStreamInterface blockingStreamInterface; PaUtilAllocationGroup *allocations; PaHostApiIndex hostApiIndex; } PaAlsaHostApiRepresentation; typedef struct PaAlsaDeviceInfo { PaDeviceInfo commonDeviceInfo; char *alsaName; int isPlug; int minInputChannels; int minOutputChannels; } PaAlsaDeviceInfo; /* Threading utilities */ static void InitializeThreading( PaAlsaThreading *th, PaUtilCpuLoadMeasurer *clm ) { th->watchdogRunning = 0; th->rtSched = 0; th->callbackTime = 0; th->callbackCpuTime = 0; th->useWatchdog = 1; th->throttledSleepTime = 0; th->cpuLoadMeasurer = clm; th->rtPrio = (sched_get_priority_max( SCHED_FIFO ) - sched_get_priority_min( SCHED_FIFO )) / 2 + sched_get_priority_min( SCHED_FIFO ); } static PaError KillCallbackThread( PaAlsaThreading *th, int wait, PaError *exitResult, PaError *watchdogExitResult ) { PaError result = paNoError; void *pret; if( exitResult ) *exitResult = paNoError; if( watchdogExitResult ) *watchdogExitResult = paNoError; if( th->watchdogRunning ) { pthread_cancel( th->watchdogThread ); ENSURE_SYSTEM_( pthread_join( th->watchdogThread, &pret ), 0 ); if( pret && pret != PTHREAD_CANCELED ) { if( watchdogExitResult ) *watchdogExitResult = *(PaError *) pret; free( pret ); } } /* Only kill the thread if it isn't in the process of stopping (flushing adaptation buffers) */ /* TODO: Make join time out */ if( !wait ) { PA_DEBUG(( "%s: Canceling thread %d\n", __FUNCTION__, th->callbackThread )); pthread_cancel( th->callbackThread ); /* XXX: Safe to call this if the thread has exited on its own? */ } PA_DEBUG(( "%s: Joining thread %d\n", __FUNCTION__, th->callbackThread )); ENSURE_SYSTEM_( pthread_join( th->callbackThread, &pret ), 0 ); if( pret && pret != PTHREAD_CANCELED ) { if( exitResult ) *exitResult = *(PaError *) pret; free( pret ); } error: return result; } /** Lock a pthread_mutex_t. * * @concern ThreadCancellation We're disabling thread cancellation while the thread is holding a lock, so mutexes are * properly unlocked at termination time. */ static PaError LockMutex( pthread_mutex_t *mtx ) { PaError result = paNoError; int oldState; ENSURE_SYSTEM_( pthread_setcancelstate( PTHREAD_CANCEL_DISABLE, &oldState ), 0 ); ENSURE_SYSTEM_( pthread_mutex_lock( mtx ), 0 ); error: return result; } /** Unlock a pthread_mutex_t. * * @concern ThreadCancellation Thread cancellation is enabled again after the mutex is properly unlocked. */ static PaError UnlockMutex( pthread_mutex_t *mtx ) { PaError result = paNoError; int oldState; ENSURE_SYSTEM_( pthread_mutex_unlock( mtx ), 0 ); ENSURE_SYSTEM_( pthread_setcancelstate( PTHREAD_CANCEL_ENABLE, &oldState ), 0 ); error: return result; } static void OnWatchdogExit( void *userData ) { PaAlsaThreading *th = (PaAlsaThreading *) userData; struct sched_param spm = { 0 }; assert( th ); ASSERT_CALL_( pthread_setschedparam( th->callbackThread, SCHED_OTHER, &spm ), 0 ); /* Lower before exiting */ PA_DEBUG(( "Watchdog exiting\n" )); } static PaError BoostPriority( PaAlsaThreading *th ) { PaError result = paNoError; struct sched_param spm = { 0 }; spm.sched_priority = th->rtPrio; assert( th ); if( pthread_setschedparam( th->callbackThread, SCHED_FIFO, &spm ) != 0 ) { PA_UNLESS( errno == EPERM, paInternalError ); /* Lack permission to raise priority */ PA_DEBUG(( "Failed bumping priority\n" )); result = 0; } else result = 1; /* Success */ error: return result; } static void *WatchdogFunc( void *userData ) { PaError result = paNoError, *pres = NULL; int err; PaAlsaThreading *th = (PaAlsaThreading *) userData; unsigned intervalMsec = 500; const PaTime maxSeconds = 3.; /* Max seconds between callbacks */ PaTime timeThen = PaUtil_GetTime(), timeNow, timeElapsed, cpuTimeThen, cpuTimeNow, cpuTimeElapsed; double cpuLoad, avgCpuLoad = 0.; int throttled = 0; assert( th ); /* Execute OnWatchdogExit when exiting */ pthread_cleanup_push( &OnWatchdogExit, th ); /* Boost priority of callback thread */ PA_ENSURE( result = BoostPriority( th ) ); if( !result ) { /* Boost failed, might as well exit */ pthread_exit( NULL ); } cpuTimeThen = th->callbackCpuTime; { int policy; struct sched_param spm = { 0 }; pthread_getschedparam( pthread_self(), &policy, &spm ); PA_DEBUG(( "%s: Watchdog priority is %d\n", __FUNCTION__, spm.sched_priority )); } while( 1 ) { double lowpassCoeff = 0.9, lowpassCoeff1 = 0.99999 - lowpassCoeff; /* Test before and after in case whatever underlying sleep call isn't interrupted by pthread_cancel */ pthread_testcancel(); Pa_Sleep( intervalMsec ); pthread_testcancel(); if( PaUtil_GetTime() - th->callbackTime > maxSeconds ) { PA_DEBUG(( "Watchdog: Terminating callback thread\n" )); /* Tell thread to terminate */ err = pthread_kill( th->callbackThread, SIGKILL ); pthread_exit( NULL ); } PA_DEBUG(( "%s: PortAudio reports CPU load: %g\n", __FUNCTION__, PaUtil_GetCpuLoad( th->cpuLoadMeasurer ) )); /* Check if we should throttle, or unthrottle :P */ cpuTimeNow = th->callbackCpuTime; cpuTimeElapsed = cpuTimeNow - cpuTimeThen; cpuTimeThen = cpuTimeNow; timeNow = PaUtil_GetTime(); timeElapsed = timeNow - timeThen; timeThen = timeNow; cpuLoad = cpuTimeElapsed / timeElapsed; avgCpuLoad = avgCpuLoad * lowpassCoeff + cpuLoad * lowpassCoeff1; /* if( throttled ) PA_DEBUG(( "Watchdog: CPU load: %g, %g\n", avgCpuLoad, cpuTimeElapsed )); */ if( PaUtil_GetCpuLoad( th->cpuLoadMeasurer ) > .925 ) { static int policy; static struct sched_param spm = { 0 }; static const struct sched_param defaultSpm = { 0 }; PA_DEBUG(( "%s: Throttling audio thread, priority %d\n", __FUNCTION__, spm.sched_priority )); pthread_getschedparam( th->callbackThread, &policy, &spm ); if( !pthread_setschedparam( th->callbackThread, SCHED_OTHER, &defaultSpm ) ) { throttled = 1; } else PA_DEBUG(( "Watchdog: Couldn't lower priority of audio thread: %s\n", strerror( errno ) )); /* Give other processes a go, before raising priority again */ PA_DEBUG(( "%s: Watchdog sleeping for %lu msecs before unthrottling\n", __FUNCTION__, th->throttledSleepTime )); Pa_Sleep( th->throttledSleepTime ); /* Reset callback priority */ if( pthread_setschedparam( th->callbackThread, SCHED_FIFO, &spm ) != 0 ) { PA_DEBUG(( "%s: Couldn't raise priority of audio thread: %s\n", __FUNCTION__, strerror( errno ) )); } if( PaUtil_GetCpuLoad( th->cpuLoadMeasurer ) >= .99 ) intervalMsec = 50; else intervalMsec = 100; /* lowpassCoeff = .97; lowpassCoeff1 = .99999 - lowpassCoeff; */ } else if( throttled && avgCpuLoad < .8 ) { intervalMsec = 500; throttled = 0; /* lowpassCoeff = .9; lowpassCoeff1 = .99999 - lowpassCoeff; */ } } pthread_cleanup_pop( 1 ); /* Execute cleanup on exit */ error: /* Shouldn't get here in the normal case */ /* Pass on error code */ pres = malloc( sizeof (PaError) ); *pres = result; pthread_exit( pres ); } static PaError CreateCallbackThread( PaAlsaThreading *th, void *(*callbackThreadFunc)( void * ), PaStream *s ) { PaError result = paNoError; pthread_attr_t attr; int started = 0; #if defined _POSIX_MEMLOCK && (_POSIX_MEMLOCK != -1) if( th->rtSched ) { if( mlockall( MCL_CURRENT | MCL_FUTURE ) < 0 ) { int savedErrno = errno; /* In case errno gets overwritten */ assert( savedErrno != EINVAL ); /* Most likely a programmer error */ PA_UNLESS( (savedErrno == EPERM), paInternalError ); PA_DEBUG(( "%s: Failed locking memory\n", __FUNCTION__ )); } else PA_DEBUG(( "%s: Successfully locked memory\n", __FUNCTION__ )); } #endif PA_UNLESS( !pthread_attr_init( &attr ), paInternalError ); /* Priority relative to other processes */ PA_UNLESS( !pthread_attr_setscope( &attr, PTHREAD_SCOPE_SYSTEM ), paInternalError ); PA_UNLESS( !pthread_create( &th->callbackThread, &attr, callbackThreadFunc, s ), paInternalError ); started = 1; if( th->rtSched ) { if( th->useWatchdog ) { int err; struct sched_param wdSpm = { 0 }; /* Launch watchdog, watchdog sets callback thread priority */ int prio = PA_MIN( th->rtPrio + 4, sched_get_priority_max( SCHED_FIFO ) ); wdSpm.sched_priority = prio; PA_UNLESS( !pthread_attr_init( &attr ), paInternalError ); PA_UNLESS( !pthread_attr_setinheritsched( &attr, PTHREAD_EXPLICIT_SCHED ), paInternalError ); PA_UNLESS( !pthread_attr_setscope( &attr, PTHREAD_SCOPE_SYSTEM ), paInternalError ); PA_UNLESS( !pthread_attr_setschedpolicy( &attr, SCHED_FIFO ), paInternalError ); PA_UNLESS( !pthread_attr_setschedparam( &attr, &wdSpm ), paInternalError ); if( (err = pthread_create( &th->watchdogThread, &attr, &WatchdogFunc, th )) ) { PA_UNLESS( err == EPERM, paInternalError ); /* Permission error, go on without realtime privileges */ PA_DEBUG(( "Failed bumping priority\n" )); } else { int policy; th->watchdogRunning = 1; ENSURE_SYSTEM_( pthread_getschedparam( th->watchdogThread, &policy, &wdSpm ), 0 ); /* Check if priority is right, policy could potentially differ from SCHED_FIFO (but that's alright) */ if( wdSpm.sched_priority != prio ) { PA_DEBUG(( "Watchdog priority not set correctly (%d)\n", wdSpm.sched_priority )); PA_ENSURE( paInternalError ); } } } else PA_ENSURE( BoostPriority( th ) ); } end: return result; error: if( started ) KillCallbackThread( th, 0, NULL, NULL ); goto end; } static void CallbackUpdate( PaAlsaThreading *th ) { th->callbackTime = PaUtil_GetTime(); th->callbackCpuTime = PaUtil_GetCpuLoad( th->cpuLoadMeasurer ); } /* prototypes for functions declared in this file */ static void Terminate( struct PaUtilHostApiRepresentation *hostApi ); static PaError IsFormatSupported( struct PaUtilHostApiRepresentation *hostApi, const PaStreamParameters *inputParameters, const PaStreamParameters *outputParameters, double sampleRate ); static PaError OpenStream( struct PaUtilHostApiRepresentation *hostApi, PaStream** s, const PaStreamParameters *inputParameters, const PaStreamParameters *outputParameters, double sampleRate, unsigned long framesPerBuffer, PaStreamFlags streamFlags, PaStreamCallback *callback, void *userData ); static PaError CloseStream( PaStream* stream ); static PaError StartStream( PaStream *stream ); static PaError StopStream( PaStream *stream ); static PaError AbortStream( PaStream *stream ); static PaError IsStreamStopped( PaStream *s ); static PaError IsStreamActive( PaStream *stream ); static PaTime GetStreamTime( PaStream *stream ); static double GetStreamCpuLoad( PaStream* stream ); static PaError BuildDeviceList( PaAlsaHostApiRepresentation *hostApi ); static int SetApproximateSampleRate( snd_pcm_t *pcm, snd_pcm_hw_params_t *hwParams, double sampleRate ); static int GetExactSampleRate( snd_pcm_hw_params_t *hwParams, double *sampleRate ); /* Callback prototypes */ static void *CallbackThreadFunc( void *userData ); /* Blocking prototypes */ static signed long GetStreamReadAvailable( PaStream* s ); static signed long GetStreamWriteAvailable( PaStream* s ); static PaError ReadStream( PaStream* stream, void *buffer, unsigned long frames ); static PaError WriteStream( PaStream* stream, const void *buffer, unsigned long frames ); static const PaAlsaDeviceInfo *GetDeviceInfo( const PaUtilHostApiRepresentation *hostApi, int device ) { return (const PaAlsaDeviceInfo *)hostApi->deviceInfos[device]; } PaError PaAlsa_Initialize( PaUtilHostApiRepresentation **hostApi, PaHostApiIndex hostApiIndex ) { PaError result = paNoError; PaAlsaHostApiRepresentation *alsaHostApi = NULL; PA_UNLESS( alsaHostApi = (PaAlsaHostApiRepresentation*) PaUtil_AllocateMemory( sizeof(PaAlsaHostApiRepresentation) ), paInsufficientMemory ); PA_UNLESS( alsaHostApi->allocations = PaUtil_CreateAllocationGroup(), paInsufficientMemory ); alsaHostApi->hostApiIndex = hostApiIndex; *hostApi = (PaUtilHostApiRepresentation*)alsaHostApi; (*hostApi)->info.structVersion = 1; (*hostApi)->info.type = paALSA; (*hostApi)->info.name = "ALSA"; (*hostApi)->Terminate = Terminate; (*hostApi)->OpenStream = OpenStream; (*hostApi)->IsFormatSupported = IsFormatSupported; PA_ENSURE( BuildDeviceList( alsaHostApi ) ); PaUtil_InitializeStreamInterface( &alsaHostApi->callbackStreamInterface, CloseStream, StartStream, StopStream, AbortStream, IsStreamStopped, IsStreamActive, GetStreamTime, GetStreamCpuLoad, PaUtil_DummyRead, PaUtil_DummyWrite, PaUtil_DummyGetReadAvailable, PaUtil_DummyGetWriteAvailable ); PaUtil_InitializeStreamInterface( &alsaHostApi->blockingStreamInterface, CloseStream, StartStream, StopStream, AbortStream, IsStreamStopped, IsStreamActive, GetStreamTime, PaUtil_DummyGetCpuLoad, ReadStream, WriteStream, GetStreamReadAvailable, GetStreamWriteAvailable ); return result; error: if( alsaHostApi ) { if( alsaHostApi->allocations ) { PaUtil_FreeAllAllocations( alsaHostApi->allocations ); PaUtil_DestroyAllocationGroup( alsaHostApi->allocations ); } PaUtil_FreeMemory( alsaHostApi ); } return result; } static void Terminate( struct PaUtilHostApiRepresentation *hostApi ) { PaAlsaHostApiRepresentation *alsaHostApi = (PaAlsaHostApiRepresentation*)hostApi; assert( hostApi ); if( alsaHostApi->allocations ) { PaUtil_FreeAllAllocations( alsaHostApi->allocations ); PaUtil_DestroyAllocationGroup( alsaHostApi->allocations ); } PaUtil_FreeMemory( alsaHostApi ); snd_config_update_free_global(); } /*! Determine max channels and default latencies. * * This function provides functionality to grope an opened (might be opened for capture or playback) pcm device for * traits like max channels, suitable default latencies and default sample rate. Upon error, max channels is set to zero, * and a suitable result returned. The device is closed before returning. */ static PaError GropeDevice( snd_pcm_t *pcm, int *minChannels, int *maxChannels, double *defaultLowLatency, double *defaultHighLatency, double *defaultSampleRate, int isPlug ) { PaError result = paNoError; snd_pcm_hw_params_t *hwParams; snd_pcm_uframes_t lowLatency = 512, highLatency = 2048; unsigned int minChans, maxChans; double defaultSr = *defaultSampleRate; assert( pcm ); ENSURE_( snd_pcm_nonblock( pcm, 0 ), paUnanticipatedHostError ); snd_pcm_hw_params_alloca( &hwParams ); snd_pcm_hw_params_any( pcm, hwParams ); if( defaultSr >= 0 ) { /* Could be that the device opened in one mode supports samplerates that the other mode wont have, * so try again .. */ if( SetApproximateSampleRate( pcm, hwParams, defaultSr ) < 0 ) { defaultSr = -1.; PA_DEBUG(( "%s: Original default samplerate failed, trying again ..\n", __FUNCTION__ )); } } if( defaultSr < 0. ) /* Default sample rate not set */ { unsigned int sampleRate = 44100; /* Will contain approximate rate returned by alsa-lib */ ENSURE_( snd_pcm_hw_params_set_rate_near( pcm, hwParams, &sampleRate, NULL ), paUnanticipatedHostError ); ENSURE_( GetExactSampleRate( hwParams, &defaultSr ), paUnanticipatedHostError ); } ENSURE_( snd_pcm_hw_params_get_channels_min( hwParams, &minChans ), paUnanticipatedHostError ); ENSURE_( snd_pcm_hw_params_get_channels_max( hwParams, &maxChans ), paUnanticipatedHostError ); assert( maxChans <= INT_MAX ); assert( maxChans > 0 ); /* Weird linking issue could cause wrong version of ALSA symbols to be called, resulting in zeroed values */ /* XXX: Limit to sensible number (ALSA plugins accept a crazy amount of channels)? */ if( isPlug && maxChans > 128 ) { maxChans = 128; PA_DEBUG(( "%s: Limiting number of plugin channels to %u\n", __FUNCTION__, maxChans )); } /* TWEAKME: * * Giving values for default min and max latency is not * straightforward. Here are our objectives: * * * for low latency, we want to give the lowest value * that will work reliably. This varies based on the * sound card, kernel, CPU, etc. I think it is better * to give sub-optimal latency than to give a number * too low and cause dropouts. My conservative * estimate at this point is to base it on 4096-sample * latency at 44.1 kHz, which gives a latency of 23ms. * * for high latency we want to give a large enough * value that dropouts are basically impossible. This * doesn't really require as much tweaking, since * providing too large a number will just cause us to * select the nearest setting that will work at stream * config time. */ ENSURE_( snd_pcm_hw_params_set_buffer_size_near( pcm, hwParams, &lowLatency ), paUnanticipatedHostError ); /* Have to reset hwParams, to set new buffer size */ ENSURE_( snd_pcm_hw_params_any( pcm, hwParams ), paUnanticipatedHostError ); ENSURE_( snd_pcm_hw_params_set_buffer_size_near( pcm, hwParams, &highLatency ), paUnanticipatedHostError ); *minChannels = (int)minChans; *maxChannels = (int)maxChans; *defaultSampleRate = defaultSr; *defaultLowLatency = (double) lowLatency / *defaultSampleRate; *defaultHighLatency = (double) highLatency / *defaultSampleRate; end: snd_pcm_close( pcm ); return result; error: goto end; } /* Initialize device info with invalid values (maxInputChannels and maxOutputChannels are set to zero since these indicate * wether input/output is available) */ static void InitializeDeviceInfo( PaDeviceInfo *deviceInfo ) { deviceInfo->structVersion = -1; deviceInfo->name = NULL; deviceInfo->hostApi = -1; deviceInfo->maxInputChannels = 0; deviceInfo->maxOutputChannels = 0; deviceInfo->defaultLowInputLatency = -1.; deviceInfo->defaultLowOutputLatency = -1.; deviceInfo->defaultHighInputLatency = -1.; deviceInfo->defaultHighOutputLatency = -1.; deviceInfo->defaultSampleRate = -1.; } /* Helper struct */ typedef struct { char *alsaName; char *name; int isPlug; int hasPlayback; int hasCapture; } DeviceNames; static PaError PaAlsa_StrDup( PaAlsaHostApiRepresentation *alsaApi, char **dst, const char *src) { PaError result = paNoError; int len = strlen( src ) + 1; /* PA_DEBUG(("PaStrDup %s %d\n", src, len)); */ PA_UNLESS( *dst = (char *)PaUtil_GroupAllocateMemory( alsaApi->allocations, len ), paInsufficientMemory ); strncpy( *dst, src, len ); error: return result; } /* Disregard standard plugins * XXX: Might want to make the "default" plugin available, if we can make it work */ static int IgnorePlugin( const char *pluginId ) { #define numIgnored 10 static const char *ignoredPlugins[numIgnored] = {"hw", "plughw", "plug", "default", "dsnoop", "dmix", "tee", "file", "null", "shm"}; int i; for( i = 0; i < numIgnored; ++i ) { if( !strcmp( pluginId, ignoredPlugins[i] ) ) { return 1; } } return 0; } /* Build PaDeviceInfo list, ignore devices for which we cannot determine capabilities (possibly busy, sigh) */ static PaError BuildDeviceList( PaAlsaHostApiRepresentation *alsaApi ) { PaUtilHostApiRepresentation *commonApi = &alsaApi->commonHostApiRep; PaAlsaDeviceInfo *deviceInfoArray; int cardIdx = -1, devIdx = 0; snd_ctl_card_info_t *cardInfo; PaError result = paNoError; size_t numDeviceNames = 0, maxDeviceNames = 1, i; DeviceNames *deviceNames = NULL; snd_config_t *topNode = NULL; snd_pcm_info_t *pcmInfo; int res; int blocking = SND_PCM_NONBLOCK; char alsaCardName[50]; if( getenv( "PA_ALSA_INITIALIZE_BLOCK" ) && atoi( getenv( "PA_ALSA_INITIALIZE_BLOCK" ) ) ) blocking = 0; /* These two will be set to the first working input and output device, respectively */ commonApi->info.defaultInputDevice = paNoDevice; commonApi->info.defaultOutputDevice = paNoDevice; /* count the devices by enumerating all the card numbers */ /* snd_card_next() modifies the integer passed to it to be: * the index of the first card if the parameter is -1 * the index of the next card if the parameter is the index of a card * -1 if there are no more cards * * The function itself returns 0 if it succeeded. */ cardIdx = -1; snd_ctl_card_info_alloca( &cardInfo ); snd_pcm_info_alloca( &pcmInfo ); while( snd_card_next( &cardIdx ) == 0 && cardIdx >= 0 ) { char *cardName; int devIdx = -1; snd_ctl_t *ctl; char buf[50]; snprintf( alsaCardName, sizeof (alsaCardName), "hw:%d", cardIdx ); /* Acquire name of card */ if( snd_ctl_open( &ctl, alsaCardName, 0 ) < 0 ) continue; /* Unable to open card :( */ snd_ctl_card_info( ctl, cardInfo ); PA_ENSURE( PaAlsa_StrDup( alsaApi, &cardName, snd_ctl_card_info_get_name( cardInfo )) ); while( snd_ctl_pcm_next_device( ctl, &devIdx ) == 0 && devIdx >= 0 ) { char *alsaDeviceName, *deviceName; size_t len; int hasPlayback = 0, hasCapture = 0; snprintf( buf, sizeof (buf), "%s:%d,%d", "hw", cardIdx, devIdx ); /* Obtain info about this particular device */ snd_pcm_info_set_device( pcmInfo, devIdx ); snd_pcm_info_set_subdevice( pcmInfo, 0 ); snd_pcm_info_set_stream( pcmInfo, SND_PCM_STREAM_CAPTURE ); if( snd_ctl_pcm_info( ctl, pcmInfo ) >= 0 ) hasCapture = 1; snd_pcm_info_set_stream( pcmInfo, SND_PCM_STREAM_PLAYBACK ); if( snd_ctl_pcm_info( ctl, pcmInfo ) >= 0 ) hasPlayback = 1; if( !hasPlayback && !hasCapture ) { continue; /* Error */ } /* The length of the string written by snprintf plus terminating 0 */ len = snprintf( NULL, 0, "%s: %s (%s)", cardName, snd_pcm_info_get_name( pcmInfo ), buf ) + 1; PA_UNLESS( deviceName = (char *)PaUtil_GroupAllocateMemory( alsaApi->allocations, len ), paInsufficientMemory ); snprintf( deviceName, len, "%s: %s (%s)", cardName, snd_pcm_info_get_name( pcmInfo ), buf ); ++numDeviceNames; if( !deviceNames || numDeviceNames > maxDeviceNames ) { maxDeviceNames *= 2; PA_UNLESS( deviceNames = (DeviceNames *) realloc( deviceNames, maxDeviceNames * sizeof (DeviceNames) ), paInsufficientMemory ); } PA_ENSURE( PaAlsa_StrDup( alsaApi, &alsaDeviceName, buf ) ); deviceNames[ numDeviceNames - 1 ].alsaName = alsaDeviceName; deviceNames[ numDeviceNames - 1 ].name = deviceName; deviceNames[ numDeviceNames - 1 ].isPlug = 0; deviceNames[ numDeviceNames - 1 ].hasPlayback = hasPlayback; deviceNames[ numDeviceNames - 1 ].hasCapture = hasCapture; } snd_ctl_close( ctl ); } /* Iterate over plugin devices */ if( NULL == snd_config ) { /* snd_config_update is called implicitly by some functions, if this hasn't happened snd_config will be NULL (bleh) */ ENSURE_( snd_config_update(), paUnanticipatedHostError ); PA_DEBUG(( "Updating snd_config\n" )); } assert( snd_config ); if( (res = snd_config_search( snd_config, "pcm", &topNode )) >= 0 ) { snd_config_iterator_t i, next; snd_config_for_each( i, next, topNode ) { const char *tpStr = NULL, *idStr = NULL; char *alsaDeviceName, *deviceName; snd_config_t *n = snd_config_iterator_entry( i ), *tp = NULL; if( snd_config_get_type( n ) != SND_CONFIG_TYPE_COMPOUND ) continue; ENSURE_( snd_config_search( n, "type", &tp ), paUnanticipatedHostError ); ENSURE_( snd_config_get_string( tp, &tpStr ), paUnanticipatedHostError ); ENSURE_( snd_config_get_id( n, &idStr ), paUnanticipatedHostError ); if( IgnorePlugin( idStr ) ) { PA_DEBUG(( "%s: Ignoring ALSA plugin device %s of type %s\n", __FUNCTION__, idStr, tpStr )); continue; } PA_DEBUG(( "%s: Found plugin %s of type %s\n", __FUNCTION__, idStr, tpStr )); PA_UNLESS( alsaDeviceName = (char*)PaUtil_GroupAllocateMemory( alsaApi->allocations, strlen(idStr) + 6 ), paInsufficientMemory ); strcpy( alsaDeviceName, idStr ); PA_UNLESS( deviceName = (char*)PaUtil_GroupAllocateMemory( alsaApi->allocations, strlen(idStr) + 1 ), paInsufficientMemory ); strcpy( deviceName, idStr ); ++numDeviceNames; if( !deviceNames || numDeviceNames > maxDeviceNames ) { maxDeviceNames *= 2; PA_UNLESS( deviceNames = (DeviceNames *) realloc( deviceNames, maxDeviceNames * sizeof (DeviceNames) ), paInsufficientMemory ); } deviceNames[numDeviceNames - 1].alsaName = alsaDeviceName; deviceNames[numDeviceNames - 1].name = deviceName; deviceNames[numDeviceNames - 1].isPlug = 1; deviceNames[numDeviceNames - 1].hasPlayback = 1; deviceNames[numDeviceNames - 1].hasCapture = 1; } } else PA_DEBUG(( "%s: Iterating over ALSA plugins failed: %s\n", __FUNCTION__, snd_strerror( res ) )); /* allocate deviceInfo memory based on the number of devices */ PA_UNLESS( commonApi->deviceInfos = (PaDeviceInfo**)PaUtil_GroupAllocateMemory( alsaApi->allocations, sizeof(PaDeviceInfo*) * (numDeviceNames) ), paInsufficientMemory ); /* allocate all device info structs in a contiguous block */ PA_UNLESS( deviceInfoArray = (PaAlsaDeviceInfo*)PaUtil_GroupAllocateMemory( alsaApi->allocations, sizeof(PaAlsaDeviceInfo) * numDeviceNames ), paInsufficientMemory ); /* Loop over list of cards, filling in info, if a device is deemed unavailable (can't get name), * it's ignored. */ /* while( snd_card_next( &cardIdx ) == 0 && cardIdx >= 0 ) */ for( i = 0, devIdx = 0; i < numDeviceNames; ++i ) { snd_pcm_t *pcm; PaAlsaDeviceInfo *deviceInfo = &deviceInfoArray[devIdx]; PaDeviceInfo *commonDeviceInfo = &deviceInfo->commonDeviceInfo; /* Zero fields */ InitializeDeviceInfo( commonDeviceInfo ); /* to determine device capabilities, we must open the device and query the * hardware parameter configuration space */ /* Query capture */ if( deviceNames[i].hasCapture && snd_pcm_open( &pcm, deviceNames[i].alsaName, SND_PCM_STREAM_CAPTURE, blocking ) >= 0 ) { if( GropeDevice( pcm, &deviceInfo->minInputChannels, &commonDeviceInfo->maxInputChannels, &commonDeviceInfo->defaultLowInputLatency, &commonDeviceInfo->defaultHighInputLatency, &commonDeviceInfo->defaultSampleRate, deviceNames[i].isPlug ) != paNoError ) continue; /* Error */ } /* Query playback */ if( deviceNames[i].hasPlayback && snd_pcm_open( &pcm, deviceNames[i].alsaName, SND_PCM_STREAM_PLAYBACK, blocking ) >= 0 ) { if( GropeDevice( pcm, &deviceInfo->minOutputChannels, &commonDeviceInfo->maxOutputChannels, &commonDeviceInfo->defaultLowOutputLatency, &commonDeviceInfo->defaultHighOutputLatency, &commonDeviceInfo->defaultSampleRate, deviceNames[i].isPlug ) != paNoError ) continue; /* Error */ } commonDeviceInfo->structVersion = 2; commonDeviceInfo->hostApi = alsaApi->hostApiIndex; commonDeviceInfo->name = deviceNames[i].name; deviceInfo->alsaName = deviceNames[i].alsaName; deviceInfo->isPlug = deviceNames[i].isPlug; /* A: Storing pointer to PaAlsaDeviceInfo object as pointer to PaDeviceInfo object. * Should now be safe to add device info, unless the device supports neither capture nor playback */ if( commonDeviceInfo->maxInputChannels > 0 || commonDeviceInfo->maxOutputChannels > 0 ) { if( commonApi->info.defaultInputDevice == paNoDevice && commonDeviceInfo->maxInputChannels > 0 ) commonApi->info.defaultInputDevice = devIdx; if( commonApi->info.defaultOutputDevice == paNoDevice && commonDeviceInfo->maxOutputChannels > 0 ) commonApi->info.defaultOutputDevice = devIdx; commonApi->deviceInfos[devIdx++] = (PaDeviceInfo *) deviceInfo; } } free( deviceNames ); commonApi->info.deviceCount = devIdx; /* Number of successfully queried devices */ end: return result; error: /* No particular action */ goto end; } /* Check against known device capabilities */ static PaError ValidateParameters( const PaStreamParameters *parameters, PaUtilHostApiRepresentation *hostApi, StreamDirection mode ) { PaError result = paNoError; int maxChans; const PaAlsaDeviceInfo *deviceInfo = NULL; assert( parameters ); if( parameters->device != paUseHostApiSpecificDeviceSpecification ) { assert( parameters->device < hostApi->info.deviceCount ); PA_UNLESS( parameters->hostApiSpecificStreamInfo == NULL, paBadIODeviceCombination ); deviceInfo = GetDeviceInfo( hostApi, parameters->device ); } else { const PaAlsaStreamInfo *streamInfo = parameters->hostApiSpecificStreamInfo; PA_UNLESS( parameters->device == paUseHostApiSpecificDeviceSpecification, paInvalidDevice ); PA_UNLESS( streamInfo->size == sizeof (PaAlsaStreamInfo) && streamInfo->version == 1, paIncompatibleHostApiSpecificStreamInfo ); PA_UNLESS( streamInfo->deviceString != NULL, paInvalidDevice ); /* Skip further checking */ return paNoError; } assert( deviceInfo ); assert( parameters->hostApiSpecificStreamInfo == NULL ); maxChans = (StreamDirection_In == mode ? deviceInfo->commonDeviceInfo.maxInputChannels : deviceInfo->commonDeviceInfo.maxOutputChannels); PA_UNLESS( parameters->channelCount <= maxChans, paInvalidChannelCount ); error: return result; } /* Given an open stream, what sample formats are available? */ static PaSampleFormat GetAvailableFormats( snd_pcm_t *pcm ) { PaSampleFormat available = 0; snd_pcm_hw_params_t *hwParams; snd_pcm_hw_params_alloca( &hwParams ); snd_pcm_hw_params_any( pcm, hwParams ); if( snd_pcm_hw_params_test_format( pcm, hwParams, SND_PCM_FORMAT_FLOAT ) >= 0) available |= paFloat32; if( snd_pcm_hw_params_test_format( pcm, hwParams, SND_PCM_FORMAT_S32 ) >= 0) available |= paInt32; if( snd_pcm_hw_params_test_format( pcm, hwParams, SND_PCM_FORMAT_S24 ) >= 0) available |= paInt24; if( snd_pcm_hw_params_test_format( pcm, hwParams, SND_PCM_FORMAT_S16 ) >= 0) available |= paInt16; if( snd_pcm_hw_params_test_format( pcm, hwParams, SND_PCM_FORMAT_U8 ) >= 0) available |= paUInt8; if( snd_pcm_hw_params_test_format( pcm, hwParams, SND_PCM_FORMAT_S8 ) >= 0) available |= paInt8; return available; } static snd_pcm_format_t Pa2AlsaFormat( PaSampleFormat paFormat ) { switch( paFormat ) { case paFloat32: return SND_PCM_FORMAT_FLOAT; case paInt16: return SND_PCM_FORMAT_S16; case paInt24: return SND_PCM_FORMAT_S24; case paInt32: return SND_PCM_FORMAT_S32; case paInt8: return SND_PCM_FORMAT_S8; case paUInt8: return SND_PCM_FORMAT_U8; default: return SND_PCM_FORMAT_UNKNOWN; } } /** Open an ALSA pcm handle. * * The device to be open can be specified in a custom PaAlsaStreamInfo struct, or it will be a device number. In case of a * device number, it maybe specified through an env variable (PA_ALSA_PLUGHW) that we should open the corresponding plugin * device. */ static PaError AlsaOpen( const PaUtilHostApiRepresentation *hostApi, const PaStreamParameters *params, StreamDirection streamDir, snd_pcm_t **pcm ) { PaError result = paNoError; int ret; const char *deviceName = alloca( 50 ); const PaAlsaDeviceInfo *deviceInfo = NULL; PaAlsaStreamInfo *streamInfo = (PaAlsaStreamInfo *)params->hostApiSpecificStreamInfo; if( !streamInfo ) { int usePlug = 0; deviceInfo = GetDeviceInfo( hostApi, params->device ); /* If device name starts with hw: and PA_ALSA_PLUGHW is 1, we open the plughw device instead */ if( !strncmp( "hw:", deviceInfo->alsaName, 3 ) && getenv( "PA_ALSA_PLUGHW" ) ) usePlug = atoi( getenv( "PA_ALSA_PLUGHW" ) ); if( usePlug ) snprintf( (char *) deviceName, 50, "plug%s", deviceInfo->alsaName ); else deviceName = deviceInfo->alsaName; } else deviceName = streamInfo->deviceString; PA_DEBUG(( "%s: Opening device %s\n", __FUNCTION__, deviceName )); if( (ret = snd_pcm_open( pcm, deviceName, streamDir == StreamDirection_In ? SND_PCM_STREAM_CAPTURE : SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK )) < 0 ) { /* Not to be closed */ *pcm = NULL; ENSURE_( ret, ret == -EBUSY ? paDeviceUnavailable : paBadIODeviceCombination ); } ENSURE_( snd_pcm_nonblock( *pcm, 0 ), paUnanticipatedHostError ); end: return result; error: goto end; } static PaError TestParameters( const PaUtilHostApiRepresentation *hostApi, const PaStreamParameters *parameters, double sampleRate, StreamDirection streamDir ) { PaError result = paNoError; snd_pcm_t *pcm = NULL; PaSampleFormat availableFormats; /* We are able to adapt to a number of channels less than what the device supports */ unsigned int numHostChannels; PaSampleFormat hostFormat; snd_pcm_hw_params_t *hwParams; snd_pcm_hw_params_alloca( &hwParams ); if( !parameters->hostApiSpecificStreamInfo ) { const PaAlsaDeviceInfo *devInfo = GetDeviceInfo( hostApi, parameters->device ); numHostChannels = PA_MAX( parameters->channelCount, StreamDirection_In == streamDir ? devInfo->minInputChannels : devInfo->minOutputChannels ); } else numHostChannels = parameters->channelCount; PA_ENSURE( AlsaOpen( hostApi, parameters, streamDir, &pcm ) ); snd_pcm_hw_params_any( pcm, hwParams ); if( SetApproximateSampleRate( pcm, hwParams, sampleRate ) < 0 ) { result = paInvalidSampleRate; goto error; } if( snd_pcm_hw_params_set_channels( pcm, hwParams, numHostChannels ) < 0 ) { result = paInvalidChannelCount; goto error; } /* See if we can find a best possible match */ availableFormats = GetAvailableFormats( pcm ); PA_ENSURE( hostFormat = PaUtil_SelectClosestAvailableFormat( availableFormats, parameters->sampleFormat ) ); ENSURE_( snd_pcm_hw_params_set_format( pcm, hwParams, Pa2AlsaFormat( hostFormat ) ), paUnanticipatedHostError ); { /* It happens that this call fails because the device is busy */ int ret = 0; if( (ret = snd_pcm_hw_params( pcm, hwParams )) < 0) { ENSURE_( ret, ret == -EBUSY ? paDeviceUnavailable : paUnanticipatedHostError ); } } end: if( pcm ) { snd_pcm_close( pcm ); } return result; error: goto end; } static PaError IsFormatSupported( struct PaUtilHostApiRepresentation *hostApi, const PaStreamParameters *inputParameters, const PaStreamParameters *outputParameters, double sampleRate ) { int inputChannelCount = 0, outputChannelCount = 0; PaSampleFormat inputSampleFormat, outputSampleFormat; PaError result = paFormatIsSupported; if( inputParameters ) { PA_ENSURE( ValidateParameters( inputParameters, hostApi, StreamDirection_In ) ); inputChannelCount = inputParameters->channelCount; inputSampleFormat = inputParameters->sampleFormat; } if( outputParameters ) { PA_ENSURE( ValidateParameters( outputParameters, hostApi, StreamDirection_Out ) ); outputChannelCount = outputParameters->channelCount; outputSampleFormat = outputParameters->sampleFormat; } if( inputChannelCount ) { if( (result = TestParameters( hostApi, inputParameters, sampleRate, StreamDirection_In )) != paNoError ) goto error; } if ( outputChannelCount ) { if( (result = TestParameters( hostApi, outputParameters, sampleRate, StreamDirection_Out )) != paNoError ) goto error; } return paFormatIsSupported; error: return result; } static PaError PaAlsaStreamComponent_Initialize( PaAlsaStreamComponent *self, PaAlsaHostApiRepresentation *alsaApi, const PaStreamParameters *params, StreamDirection streamDir, int callbackMode ) { PaError result = paNoError; PaSampleFormat userSampleFormat = params->sampleFormat, hostSampleFormat; assert( params->channelCount > 0 ); /* Make sure things have an initial value */ memset( self, 0, sizeof (PaAlsaStreamComponent) ); if( NULL == params->hostApiSpecificStreamInfo ) { const PaAlsaDeviceInfo *devInfo = GetDeviceInfo( &alsaApi->commonHostApiRep, params->device ); self->numHostChannels = PA_MAX( params->channelCount, StreamDirection_In == streamDir ? devInfo->minInputChannels : devInfo->minOutputChannels ); } else { /* We're blissfully unaware of the minimum channelCount */ self->numHostChannels = params->channelCount; } PA_ENSURE( AlsaOpen( &alsaApi->commonHostApiRep, params, streamDir, &self->pcm ) ); self->nfds = snd_pcm_poll_descriptors_count( self->pcm ); hostSampleFormat = PaUtil_SelectClosestAvailableFormat( GetAvailableFormats( self->pcm ), userSampleFormat ); self->hostSampleFormat = hostSampleFormat; self->nativeFormat = Pa2AlsaFormat( hostSampleFormat ); self->hostInterleaved = self->userInterleaved = !(userSampleFormat & paNonInterleaved); self->numUserChannels = params->channelCount; self->streamDir = streamDir; if( !callbackMode && !self->userInterleaved ) { /* Pre-allocate non-interleaved user provided buffers */ PA_UNLESS( self->userBuffers = PaUtil_AllocateMemory( sizeof (void *) * self->numUserChannels ), paInsufficientMemory ); } error: return result; } static void PaAlsaStreamComponent_Terminate( PaAlsaStreamComponent *self ) { snd_pcm_close( self->pcm ); if( self->userBuffers ) PaUtil_FreeMemory( self->userBuffers ); } int nearbyint_(float value) { if( value - (int)value > .5 ) return (int)ceil( value ); return (int)floor( value ); } /** Initiate configuration, preparing for determining a period size suitable for both capture and playback components. * */ static PaError PaAlsaStreamComponent_InitialConfigure( PaAlsaStreamComponent *self, const PaStreamParameters *params, int primeBuffers, snd_pcm_hw_params_t *hwParams, double *sampleRate ) { /* Configuration consists of setting all of ALSA's parameters. * These parameters come in two flavors: hardware parameters * and software paramters. Hardware parameters will affect * the way the device is initialized, software parameters * affect the way ALSA interacts with me, the user-level client. */ PaError result = paNoError; snd_pcm_access_t accessMode, alternateAccessMode; int dir = 0; snd_pcm_t *pcm = self->pcm; double sr = *sampleRate; unsigned int minPeriods = 2; /* self->framesPerBuffer = framesPerHostBuffer; */ /* ... fill up the configuration space with all possibile * combinations of parameters this device will accept */ ENSURE_( snd_pcm_hw_params_any( pcm, hwParams ), paUnanticipatedHostError ); ENSURE_( snd_pcm_hw_params_set_periods_integer( pcm, hwParams ), paUnanticipatedHostError ); ENSURE_( snd_pcm_hw_params_set_period_size_integer( pcm, hwParams ), paUnanticipatedHostError ); /* I think there should be at least 2 periods (even though ALSA doesn't appear to enforce this) */ dir = 0; ENSURE_( snd_pcm_hw_params_set_periods_min( pcm, hwParams, &minPeriods, &dir ), paUnanticipatedHostError ); if( self->userInterleaved ) { accessMode = SND_PCM_ACCESS_MMAP_INTERLEAVED; alternateAccessMode = SND_PCM_ACCESS_MMAP_NONINTERLEAVED; } else { accessMode = SND_PCM_ACCESS_MMAP_NONINTERLEAVED; alternateAccessMode = SND_PCM_ACCESS_MMAP_INTERLEAVED; } /* If requested access mode fails, try alternate mode */ if( snd_pcm_hw_params_set_access( pcm, hwParams, accessMode ) < 0 ) { ENSURE_( snd_pcm_hw_params_set_access( pcm, hwParams, alternateAccessMode ), paUnanticipatedHostError ); /* Flip mode */ self->hostInterleaved = !self->userInterleaved; } ENSURE_( snd_pcm_hw_params_set_format( pcm, hwParams, self->nativeFormat ), paUnanticipatedHostError ); ENSURE_( SetApproximateSampleRate( pcm, hwParams, sr ), paInvalidSampleRate ); ENSURE_( GetExactSampleRate( hwParams, &sr ), paUnanticipatedHostError ); /* reject if there's no sample rate within 1% of the one requested */ if( (fabs( *sampleRate - sr ) / *sampleRate) > 0.01 ) { PA_DEBUG(("%s: Wanted %f, closest sample rate was %d\n", __FUNCTION__, sampleRate, sr )); PA_ENSURE( paInvalidSampleRate ); } ENSURE_( snd_pcm_hw_params_set_channels( pcm, hwParams, self->numHostChannels ), paInvalidChannelCount ); *sampleRate = sr; end: return result; error: /* No particular action */ goto end; } static PaError PaAlsaStreamComponent_FinishConfigure( PaAlsaStreamComponent *self, snd_pcm_hw_params_t* hwParams, const PaStreamParameters *params, int primeBuffers, double sampleRate, PaTime* returnedLatency ) { PaError result = paNoError; snd_pcm_sw_params_t* swParams; snd_pcm_uframes_t bufSz = 0; *returnedLatency = -1.; snd_pcm_sw_params_alloca( &swParams ); bufSz = (params->suggestedLatency * sampleRate) + self->framesPerBuffer; /* One period does not count as latency */ ENSURE_( snd_pcm_hw_params_set_buffer_size_near( self->pcm, hwParams, &bufSz ), paUnanticipatedHostError ); /* Set the parameters! */ ENSURE_( snd_pcm_hw_params( self->pcm, hwParams ), paUnanticipatedHostError ); ENSURE_( snd_pcm_hw_params_get_buffer_size( hwParams, &self->bufferSize ), paUnanticipatedHostError ); /* Latency in seconds, one period is not counted as latency */ *returnedLatency = (self->bufferSize - self->framesPerBuffer) / sampleRate; /* Now software parameters... */ ENSURE_( snd_pcm_sw_params_current( self->pcm, swParams ), paUnanticipatedHostError ); ENSURE_( snd_pcm_sw_params_set_start_threshold( self->pcm, swParams, self->framesPerBuffer ), paUnanticipatedHostError ); ENSURE_( snd_pcm_sw_params_set_stop_threshold( self->pcm, swParams, self->bufferSize ), paUnanticipatedHostError ); /* Silence buffer in the case of underrun */ if( !primeBuffers ) /* XXX: Make sense? */ { snd_pcm_uframes_t boundary; ENSURE_( snd_pcm_sw_params_get_boundary( swParams, &boundary ), paUnanticipatedHostError ); ENSURE_( snd_pcm_sw_params_set_silence_threshold( self->pcm, swParams, 0 ), paUnanticipatedHostError ); ENSURE_( snd_pcm_sw_params_set_silence_size( self->pcm, swParams, boundary ), paUnanticipatedHostError ); } ENSURE_( snd_pcm_sw_params_set_avail_min( self->pcm, swParams, self->framesPerBuffer ), paUnanticipatedHostError ); ENSURE_( snd_pcm_sw_params_set_xfer_align( self->pcm, swParams, 1 ), paUnanticipatedHostError ); ENSURE_( snd_pcm_sw_params_set_tstamp_mode( self->pcm, swParams, SND_PCM_TSTAMP_MMAP ), paUnanticipatedHostError ); /* Set the parameters! */ ENSURE_( snd_pcm_sw_params( self->pcm, swParams ), paUnanticipatedHostError ); error: return result; } static PaError PaAlsaStream_Initialize( PaAlsaStream *self, PaAlsaHostApiRepresentation *alsaApi, const PaStreamParameters *inParams, const PaStreamParameters *outParams, double sampleRate, unsigned long framesPerUserBuffer, PaStreamCallback callback, PaStreamFlags streamFlags, void *userData ) { PaError result = paNoError; assert( self ); memset( self, 0, sizeof (PaAlsaStream) ); if( NULL != callback ) { PaUtil_InitializeStreamRepresentation( &self->streamRepresentation, &alsaApi->callbackStreamInterface, callback, userData ); self->callbackMode = 1; } else { PaUtil_InitializeStreamRepresentation( &self->streamRepresentation, &alsaApi->blockingStreamInterface, NULL, userData ); } self->framesPerUserBuffer = framesPerUserBuffer; self->neverDropInput = streamFlags & paNeverDropInput; /* XXX: Ignore paPrimeOutputBuffersUsingStreamCallback untill buffer priming is fully supported in pa_process.c */ /* if( outParams & streamFlags & paPrimeOutputBuffersUsingStreamCallback ) self->primeBuffers = 1; */ memset( &self->capture, 0, sizeof (PaAlsaStreamComponent) ); memset( &self->playback, 0, sizeof (PaAlsaStreamComponent) ); if( inParams ) PA_ENSURE( PaAlsaStreamComponent_Initialize( &self->capture, alsaApi, inParams, StreamDirection_In, NULL != callback ) ); if( outParams ) PA_ENSURE( PaAlsaStreamComponent_Initialize( &self->playback, alsaApi, outParams, StreamDirection_Out, NULL != callback ) ); assert( self->capture.nfds || self->playback.nfds ); PA_UNLESS( self->pfds = (struct pollfd*)PaUtil_AllocateMemory( (self->capture.nfds + self->playback.nfds) * sizeof (struct pollfd) ), paInsufficientMemory ); PaUtil_InitializeCpuLoadMeasurer( &self->cpuLoadMeasurer, sampleRate ); InitializeThreading( &self->threading, &self->cpuLoadMeasurer ); ASSERT_CALL_( pthread_mutex_init( &self->stateMtx, NULL ), 0 ); ASSERT_CALL_( pthread_mutex_init( &self->startMtx, NULL ), 0 ); ASSERT_CALL_( pthread_cond_init( &self->startCond, NULL ), 0 ); error: return result; } /** Free resources associated with stream, and eventually stream itself. * * Frees allocated memory, and terminates individual StreamComponents. */ static void PaAlsaStream_Terminate( PaAlsaStream *self ) { assert( self ); if( self->capture.pcm ) { PaAlsaStreamComponent_Terminate( &self->capture ); } if( self->playback.pcm ) { PaAlsaStreamComponent_Terminate( &self->playback ); } PaUtil_FreeMemory( self->pfds ); ASSERT_CALL_( pthread_mutex_destroy( &self->stateMtx ), 0 ); ASSERT_CALL_( pthread_mutex_destroy( &self->startMtx ), 0 ); ASSERT_CALL_( pthread_cond_destroy( &self->startCond ), 0 ); PaUtil_FreeMemory( self ); } /** Calculate polling timeout * * @param frames Time to wait * @return Polling timeout in milliseconds */ static int CalculatePollTimeout( const PaAlsaStream *stream, unsigned long frames ) { assert( stream->streamRepresentation.streamInfo.sampleRate > 0.0 ); /* Period in msecs, rounded up */ return (int)ceil( 1000 * frames / stream->streamRepresentation.streamInfo.sampleRate ); } static PaError PaAlsaStreamComponent_DetermineFramesPerBuffer( PaAlsaStreamComponent* self, const PaStreamParameters* params, unsigned long framesPerUserBuffer, double sampleRate, snd_pcm_hw_params_t* hwParams ) { PaError result = paNoError; unsigned long bufferSize = params->suggestedLatency * sampleRate, framesPerHostBuffer; int dir = 0; { snd_pcm_uframes_t tmp; snd_pcm_hw_params_get_buffer_size_min(hwParams, &tmp); bufferSize = PA_MAX(bufferSize, tmp); snd_pcm_hw_params_get_buffer_size_max(hwParams, &tmp); bufferSize = PA_MIN(bufferSize, tmp); } assert(bufferSize > 0); if( framesPerUserBuffer != paFramesPerBufferUnspecified ) { /* Preferably the host buffer size should be a multiple of the user buffer size */ if( bufferSize > framesPerUserBuffer ) { snd_pcm_uframes_t remainder = bufferSize % framesPerUserBuffer; if( remainder > framesPerUserBuffer / 2. ) bufferSize += framesPerUserBuffer - remainder; else bufferSize -= remainder; assert( bufferSize % framesPerUserBuffer == 0 ); } else if( framesPerUserBuffer % bufferSize != 0 ) { /* Find a good compromise between user specified latency and buffer size */ if( bufferSize > framesPerUserBuffer * .75 ) { bufferSize = framesPerUserBuffer; } else { snd_pcm_uframes_t newSz = framesPerUserBuffer; while( newSz / 2 >= bufferSize ) { if( framesPerUserBuffer % (newSz / 2) != 0 ) { /* No use dividing any further */ break; } newSz /= 2; } bufferSize = newSz; } assert( framesPerUserBuffer % bufferSize == 0 ); } } /* Using 5 as a base number of periods, we try to approximate the suggested latency (+1 period), finding a combination of period/buffer size which best fits these constraints */ { unsigned numPeriods = 4, maxPeriods = 0; /* It may be that the device only supports 2 periods for instance */ dir = 0; ENSURE_( snd_pcm_hw_params_get_periods_max( hwParams, &maxPeriods, &dir ), paUnanticipatedHostError ); assert( maxPeriods > 1 ); /* One period is not counted as latency */ maxPeriods -= 1; numPeriods = PA_MIN( maxPeriods, numPeriods ); if( framesPerUserBuffer != paFramesPerBufferUnspecified ) { framesPerHostBuffer = framesPerUserBuffer; if( framesPerHostBuffer < bufferSize ) { while( bufferSize / framesPerHostBuffer > numPeriods ) { framesPerHostBuffer *= 2; } } else { while( bufferSize / framesPerHostBuffer < numPeriods ) { if( framesPerUserBuffer % (framesPerHostBuffer / 2) != 0 ) { /* Can't be divided any further */ break; } framesPerHostBuffer /= 2; } } if( framesPerHostBuffer < framesPerUserBuffer ) { assert( framesPerUserBuffer % framesPerHostBuffer == 0 ); if( snd_pcm_hw_params_test_period_size( self->pcm, hwParams, framesPerHostBuffer, 0 ) < 0 ) { if( snd_pcm_hw_params_test_period_size( self->pcm, hwParams, framesPerHostBuffer * 2, 0 ) == 0 ) framesPerHostBuffer *= 2; else if( snd_pcm_hw_params_test_period_size( self->pcm, hwParams, framesPerHostBuffer / 2, 0 ) == 0 ) framesPerHostBuffer /= 2; } } else { assert( framesPerHostBuffer % framesPerUserBuffer == 0 ); if( snd_pcm_hw_params_test_period_size( self->pcm, hwParams, framesPerHostBuffer, 0 ) < 0 ) { if( snd_pcm_hw_params_test_period_size( self->pcm, hwParams, framesPerHostBuffer + framesPerUserBuffer, 0 ) == 0 ) framesPerHostBuffer += framesPerUserBuffer; else if( snd_pcm_hw_params_test_period_size( self->pcm, hwParams, framesPerHostBuffer - framesPerUserBuffer, 0 ) == 0 ) framesPerHostBuffer -= framesPerUserBuffer; } } } else { framesPerHostBuffer = bufferSize / numPeriods; } } assert( framesPerHostBuffer > 0 ); dir = 0; ENSURE_( snd_pcm_hw_params_set_period_size_near( self->pcm, hwParams, &framesPerHostBuffer, &dir ), paUnanticipatedHostError ); self->framesPerBuffer = framesPerHostBuffer; error: return result; } /* We need to determine how many frames per host buffer (period) to use. Our * goals are to provide the best possible performance, but also to * honor the requested latency settings as closely as we can. Therefore this * decision is based on: * * - the period sizes that playback and/or capture support. The * host buffer size has to be one of these. * - the number of periods that playback and/or capture support. * * We want to make period_size*(num_periods-1) to be as close as possible * to latency*rate for both playback and capture. * * This method will determine suitable period sizes for capture and playback handles, and report the maximum number of * frames per host buffer. The latter is relevant, in case we should be so unfortunate that the period size differs * between capture and playback. If this should happen, the stream's hostBufferSizeMode attribute will be set to * paUtilBoundedHostBufferSize, because the best we can do is limit the size of individual host buffers to the upper * bound. The size of host buffers scheduled for processing should only matter if the user has specified a buffer size, * but when he/she does we must strive for an optimal configuration. By default we'll opt for a fixed host buffer size, * which should be fine if the period size is the same for capture and playback. In general, if there is a specified user * buffer size, this method tries it best to determine a period size which is a multiple of the user buffer size. * * The framesPerBuffer attributes of the individual capture and playback components of the stream are set to corresponding * values determined here. Since these should be reported as * * This is one of those blocks of code that will just take a lot of * refinement to be any good. * * In the full-duplex case it is possible that the routine was unable * to find a number of frames per buffer acceptable to both devices * TODO: Implement an algorithm to find the value closest to acceptance * by both devices, to minimize difference between period sizes? */ static PaError PaAlsaStream_DetermineFramesPerBuffer( PaAlsaStream* self, double sampleRate, const PaStreamParameters* inputParameters, const PaStreamParameters* outputParameters, unsigned long framesPerUserBuffer, snd_pcm_hw_params_t* hwParamsCapture, snd_pcm_hw_params_t* hwParamsPlayback, PaUtilHostBufferSizeMode* hostBufferSizeMode ) { PaError result = paNoError; unsigned long framesPerHostBuffer = 0; int dir = 0; if( self->capture.pcm && self->playback.pcm ) { if( framesPerUserBuffer == paFramesPerBufferUnspecified ) { snd_pcm_uframes_t desiredLatency, e, minPeriodSize, maxPeriodSize, optimalPeriodSize, periodSize, minCapture, minPlayback, maxCapture, maxPlayback; /* Come up with a common desired latency */ dir = 0; ENSURE_( snd_pcm_hw_params_get_period_size_min( hwParamsCapture, &minCapture, &dir ), paUnanticipatedHostError ); dir = 0; ENSURE_( snd_pcm_hw_params_get_period_size_min( hwParamsPlayback, &minPlayback, &dir ), paUnanticipatedHostError ); dir = 0; ENSURE_( snd_pcm_hw_params_get_period_size_max( hwParamsCapture, &maxCapture, &dir ), paUnanticipatedHostError ); dir = 0; ENSURE_( snd_pcm_hw_params_get_period_size_max( hwParamsPlayback, &maxPlayback, &dir ), paUnanticipatedHostError ); minPeriodSize = PA_MAX( minPlayback, minCapture ); maxPeriodSize = PA_MIN( maxPlayback, maxCapture ); PA_UNLESS( minPeriodSize <= maxPeriodSize, paBadIODeviceCombination ); desiredLatency = (snd_pcm_uframes_t)(PA_MIN( outputParameters->suggestedLatency, inputParameters->suggestedLatency ) * sampleRate); /* Clamp desiredLatency */ { snd_pcm_uframes_t maxBufferSize; snd_pcm_uframes_t maxBufferSizeCapture, maxBufferSizePlayback; ENSURE_( snd_pcm_hw_params_get_buffer_size_max( hwParamsCapture, &maxBufferSizeCapture ), paUnanticipatedHostError ); ENSURE_( snd_pcm_hw_params_get_buffer_size_max( hwParamsPlayback, &maxBufferSizePlayback ), paUnanticipatedHostError ); maxBufferSize = PA_MIN( maxBufferSizeCapture, maxBufferSizePlayback ); desiredLatency = PA_MIN( desiredLatency, maxBufferSize ); } /* Find the closest power of 2 */ e = ilogb( minPeriodSize ); if( minPeriodSize & (minPeriodSize - 1) ) e += 1; periodSize = (snd_pcm_uframes_t)pow( 2, e ); while( periodSize <= maxPeriodSize ) { if( snd_pcm_hw_params_test_period_size( self->playback.pcm, hwParamsPlayback, periodSize, 0 ) >= 0 && snd_pcm_hw_params_test_period_size( self->capture.pcm, hwParamsCapture, periodSize, 0 ) >= 0 ) break; /* Ok! */ periodSize *= 2; } /* 4 periods considered optimal */ optimalPeriodSize = PA_MAX( desiredLatency / 4, minPeriodSize ); optimalPeriodSize = PA_MIN( optimalPeriodSize, maxPeriodSize ); /* Find the closest power of 2 */ e = ilogb( optimalPeriodSize ); if( optimalPeriodSize & (optimalPeriodSize - 1) ) e += 1; optimalPeriodSize = (snd_pcm_uframes_t)pow( 2, e ); while( optimalPeriodSize >= periodSize ) { if( snd_pcm_hw_params_test_period_size( self->capture.pcm, hwParamsCapture, optimalPeriodSize, 0 ) < 0 ) continue; if( snd_pcm_hw_params_test_period_size( self->playback.pcm, hwParamsPlayback, optimalPeriodSize, 0 ) >= 0 ) break; optimalPeriodSize /= 2; } if( optimalPeriodSize > periodSize ) periodSize = optimalPeriodSize; if( periodSize <= maxPeriodSize ) { /* Looks good, the periodSize _should_ be acceptable by both devices */ ENSURE_( snd_pcm_hw_params_set_period_size( self->capture.pcm, hwParamsCapture, periodSize, 0 ), paUnanticipatedHostError ); ENSURE_( snd_pcm_hw_params_set_period_size( self->playback.pcm, hwParamsPlayback, periodSize, 0 ), paUnanticipatedHostError ); self->capture.framesPerBuffer = self->playback.framesPerBuffer = periodSize; framesPerHostBuffer = periodSize; } else { /* Unable to find a common period size, oh well */ optimalPeriodSize = PA_MAX( desiredLatency / 4, minPeriodSize ); optimalPeriodSize = PA_MIN( optimalPeriodSize, maxPeriodSize ); self->capture.framesPerBuffer = optimalPeriodSize; dir = 0; ENSURE_( snd_pcm_hw_params_set_period_size_near( self->capture.pcm, hwParamsCapture, &self->capture.framesPerBuffer, &dir ), paUnanticipatedHostError ); self->playback.framesPerBuffer = optimalPeriodSize; dir = 0; ENSURE_( snd_pcm_hw_params_set_period_size_near( self->playback.pcm, hwParamsPlayback, &self->playback.framesPerBuffer, &dir ), paUnanticipatedHostError ); framesPerHostBuffer = PA_MAX( self->capture.framesPerBuffer, self->playback.framesPerBuffer ); *hostBufferSizeMode = paUtilBoundedHostBufferSize; } } else { /* We choose the simple route and determine a suitable number of frames per buffer for one component of * the stream, then we hope that this will work for the other component too (it should!). */ unsigned maxPeriods = 0; PaAlsaStreamComponent* first = &self->capture, * second = &self->playback; const PaStreamParameters* firstStreamParams = inputParameters; snd_pcm_hw_params_t* firstHwParams = hwParamsCapture, * secondHwParams = hwParamsPlayback; dir = 0; ENSURE_( snd_pcm_hw_params_get_periods_max( hwParamsPlayback, &maxPeriods, &dir ), paUnanticipatedHostError ); if( maxPeriods < 4 ) { /* The playback component is tricker to get right, try that first */ first = &self->playback; second = &self->capture; firstStreamParams = outputParameters; firstHwParams = hwParamsPlayback; secondHwParams = hwParamsCapture; } PA_ENSURE( PaAlsaStreamComponent_DetermineFramesPerBuffer( first, firstStreamParams, framesPerUserBuffer, sampleRate, firstHwParams ) ); second->framesPerBuffer = first->framesPerBuffer; dir = 0; ENSURE_( snd_pcm_hw_params_set_period_size_near( second->pcm, secondHwParams, &second->framesPerBuffer, &dir ), paUnanticipatedHostError ); if( self->capture.framesPerBuffer == self->playback.framesPerBuffer ) { framesPerHostBuffer = self->capture.framesPerBuffer; } else { framesPerHostBuffer = PA_MAX( self->capture.framesPerBuffer, self->playback.framesPerBuffer ); *hostBufferSizeMode = paUtilBoundedHostBufferSize; } } } else /* half-duplex is a slightly simpler case */ { if( self->capture.pcm ) { PA_ENSURE( PaAlsaStreamComponent_DetermineFramesPerBuffer( &self->capture, inputParameters, framesPerUserBuffer, sampleRate, hwParamsCapture) ); framesPerHostBuffer = self->capture.framesPerBuffer; } else { assert( self->playback.pcm ); PA_ENSURE( PaAlsaStreamComponent_DetermineFramesPerBuffer( &self->playback, outputParameters, framesPerUserBuffer, sampleRate, hwParamsPlayback ) ); framesPerHostBuffer = self->playback.framesPerBuffer; } } PA_UNLESS( framesPerHostBuffer != 0, paInternalError ); self->maxFramesPerHostBuffer = framesPerHostBuffer; error: return result; } /** Set up ALSA stream parameters. * */ static PaError PaAlsaStream_Configure( PaAlsaStream *self, const PaStreamParameters *inParams, const PaStreamParameters* outParams, double sampleRate, unsigned long framesPerUserBuffer, double* inputLatency, double* outputLatency, PaUtilHostBufferSizeMode* hostBufferSizeMode ) { PaError result = paNoError; double realSr = sampleRate; snd_pcm_hw_params_t* hwParamsCapture, * hwParamsPlayback; snd_pcm_hw_params_alloca( &hwParamsCapture ); snd_pcm_hw_params_alloca( &hwParamsPlayback ); if( self->capture.pcm ) PA_ENSURE( PaAlsaStreamComponent_InitialConfigure( &self->capture, inParams, self->primeBuffers, hwParamsCapture, &realSr ) ); if( self->playback.pcm ) PA_ENSURE( PaAlsaStreamComponent_InitialConfigure( &self->playback, outParams, self->primeBuffers, hwParamsPlayback, &realSr ) ); PA_ENSURE( PaAlsaStream_DetermineFramesPerBuffer( self, realSr, inParams, outParams, framesPerUserBuffer, hwParamsCapture, hwParamsPlayback, hostBufferSizeMode ) ); if( self->capture.pcm ) { assert( self->capture.framesPerBuffer != 0 ); PA_ENSURE( PaAlsaStreamComponent_FinishConfigure( &self->capture, hwParamsCapture, inParams, self->primeBuffers, realSr, inputLatency ) ); PA_DEBUG(( "%s: Capture period size: %lu, latency: %f\n", __FUNCTION__, self->capture.framesPerBuffer, *inputLatency )); } if( self->playback.pcm ) { assert( self->playback.framesPerBuffer != 0 ); PA_ENSURE( PaAlsaStreamComponent_FinishConfigure( &self->playback, hwParamsPlayback, outParams, self->primeBuffers, realSr, outputLatency ) ); PA_DEBUG(( "%s: Playback period size: %lu, latency: %f\n", __FUNCTION__, self->playback.framesPerBuffer, *outputLatency )); } /* Should be exact now */ self->streamRepresentation.streamInfo.sampleRate = realSr; /* this will cause the two streams to automatically start/stop/prepare in sync. * We only need to execute these operations on one of the pair. * A: We don't want to do this on a blocking stream. */ if( self->callbackMode && self->capture.pcm && self->playback.pcm ) { int err = snd_pcm_link( self->capture.pcm, self->playback.pcm ); if( err == 0 ) self->pcmsSynced = 1; else PA_DEBUG(( "%s: Unable to sync pcms: %s\n", __FUNCTION__, snd_strerror( err ) )); } { unsigned long minFramesPerHostBuffer = PA_MIN( self->capture.pcm ? self->capture.framesPerBuffer : ULONG_MAX, self->playback.pcm ? self->playback.framesPerBuffer : ULONG_MAX ); self->pollTimeout = CalculatePollTimeout( self, minFramesPerHostBuffer ); /* Period in msecs, rounded up */ /* Time before watchdog unthrottles realtime thread == 1/4 of period time in msecs */ self->threading.throttledSleepTime = (unsigned long) (minFramesPerHostBuffer / sampleRate / 4 * 1000); } if( self->callbackMode ) { /* If the user expects a certain number of frames per callback we will either have to rely on block adaption * (framesPerHostBuffer is not an integer multiple of framesPerBuffer) or we can simply align the number * of host buffer frames with what the user specified */ if( self->framesPerUserBuffer != paFramesPerBufferUnspecified ) { /* self->alignFrames = 1; */ /* Unless the ratio between number of host and user buffer frames is an integer we will have to rely * on block adaption */ /* if( framesPerHostBuffer % framesPerBuffer != 0 || (self->capture.pcm && self->playback.pcm && self->capture.framesPerBuffer != self->playback.framesPerBuffer) ) self->useBlockAdaption = 1; else self->alignFrames = 1; */ } } error: return result; } static PaError OpenStream( struct PaUtilHostApiRepresentation *hostApi, PaStream** s, const PaStreamParameters *inputParameters, const PaStreamParameters *outputParameters, double sampleRate, unsigned long framesPerBuffer, PaStreamFlags streamFlags, PaStreamCallback* callback, void *userData ) { PaError result = paNoError; PaAlsaHostApiRepresentation *alsaHostApi = (PaAlsaHostApiRepresentation*)hostApi; PaAlsaStream *stream = NULL; PaSampleFormat hostInputSampleFormat = 0, hostOutputSampleFormat = 0; PaSampleFormat inputSampleFormat = 0, outputSampleFormat = 0; int numInputChannels = 0, numOutputChannels = 0; PaTime inputLatency, outputLatency; PaUtilHostBufferSizeMode hostBufferSizeMode = paUtilFixedHostBufferSize; if( (streamFlags & paPlatformSpecificFlags) != 0 ) return paInvalidFlag; if( inputParameters ) { PA_ENSURE( ValidateParameters( inputParameters, hostApi, StreamDirection_In ) ); numInputChannels = inputParameters->channelCount; inputSampleFormat = inputParameters->sampleFormat; } if( outputParameters ) { PA_ENSURE( ValidateParameters( outputParameters, hostApi, StreamDirection_Out ) ); numOutputChannels = outputParameters->channelCount; outputSampleFormat = outputParameters->sampleFormat; } /* XXX: Why do we support this anyway? */ if( framesPerBuffer == paFramesPerBufferUnspecified && getenv( "PA_ALSA_PERIODSIZE" ) != NULL ) { PA_DEBUG(( "%s: Getting framesPerBuffer from environment\n", __FUNCTION__ )); framesPerBuffer = atoi( getenv("PA_ALSA_PERIODSIZE") ); } PA_UNLESS( stream = (PaAlsaStream*)PaUtil_AllocateMemory( sizeof(PaAlsaStream) ), paInsufficientMemory ); PA_ENSURE( PaAlsaStream_Initialize( stream, alsaHostApi, inputParameters, outputParameters, sampleRate, framesPerBuffer, callback, streamFlags, userData ) ); PA_ENSURE( PaAlsaStream_Configure( stream, inputParameters, outputParameters, sampleRate, framesPerBuffer, &inputLatency, &outputLatency, &hostBufferSizeMode ) ); if( stream->capture.pcm && stream->playback.pcm ) { /* In full-duplex mode, host buffers should be of a fixed size unless we were unable to match the period * sizes of the two handles */ if( hostBufferSizeMode == paUtilFixedHostBufferSize ) { PA_UNLESS( stream->capture.framesPerBuffer == stream->playback.framesPerBuffer, paInternalError ); } else { assert( hostBufferSizeMode == paUtilBoundedHostBufferSize ); PA_UNLESS( stream->capture.framesPerBuffer != stream->playback.framesPerBuffer, paInternalError ); } } else { if( stream->capture.pcm ) { PA_UNLESS( stream->maxFramesPerHostBuffer == stream->capture.framesPerBuffer, paInternalError ); } else { PA_UNLESS( stream->maxFramesPerHostBuffer == stream->playback.framesPerBuffer, paInternalError ); } } hostInputSampleFormat = stream->capture.hostSampleFormat; hostOutputSampleFormat = stream->playback.hostSampleFormat; PA_ENSURE( PaUtil_InitializeBufferProcessor( &stream->bufferProcessor, numInputChannels, inputSampleFormat, hostInputSampleFormat, numOutputChannels, outputSampleFormat, hostOutputSampleFormat, sampleRate, streamFlags, framesPerBuffer, stream->maxFramesPerHostBuffer, hostBufferSizeMode, callback, userData ) ); /* Ok, buffer processor is initialized, now we can deduce it's latency */ if( numInputChannels > 0 ) stream->streamRepresentation.streamInfo.inputLatency = inputLatency + PaUtil_GetBufferProcessorInputLatency( &stream->bufferProcessor ); if( numOutputChannels > 0 ) stream->streamRepresentation.streamInfo.outputLatency = outputLatency + PaUtil_GetBufferProcessorOutputLatency( &stream->bufferProcessor ); *s = (PaStream*)stream; return result; error: if( stream ) { PA_DEBUG(( "%s: Stream in error, terminating\n", __FUNCTION__ )); PaAlsaStream_Terminate( stream ); } return result; } static PaError CloseStream( PaStream* s ) { PaError result = paNoError; PaAlsaStream *stream = (PaAlsaStream*)s; PaUtil_TerminateBufferProcessor( &stream->bufferProcessor ); PaUtil_TerminateStreamRepresentation( &stream->streamRepresentation ); PaAlsaStream_Terminate( stream ); return result; } static void SilenceBuffer( PaAlsaStream *stream ) { const snd_pcm_channel_area_t *areas; snd_pcm_uframes_t frames = (snd_pcm_uframes_t)snd_pcm_avail_update( stream->playback.pcm ), offset; snd_pcm_mmap_begin( stream->playback.pcm, &areas, &offset, &frames ); snd_pcm_areas_silence( areas, offset, stream->playback.numHostChannels, frames, stream->playback.nativeFormat ); snd_pcm_mmap_commit( stream->playback.pcm, offset, frames ); } /** Start/prepare pcm(s) for streaming. * * Depending on wether the stream is in callback or blocking mode, we will respectively start or simply * prepare the playback pcm. If the buffer has _not_ been primed, we will in callback mode prepare and * silence the buffer before starting playback. In blocking mode we simply prepare, as the playback will * be started automatically as the user writes to output. * * The capture pcm, however, will simply be prepared and started. * * PaAlsaStream::startMtx makes sure access is synchronized (useful in callback mode) */ static PaError AlsaStart( PaAlsaStream *stream, int priming ) { PaError result = paNoError; if( stream->playback.pcm ) { if( stream->callbackMode ) { if( !priming ) { /* Buffer isn't primed, so prepare and silence */ ENSURE_( snd_pcm_prepare( stream->playback.pcm ), paUnanticipatedHostError ); SilenceBuffer( stream ); } ENSURE_( snd_pcm_start( stream->playback.pcm ), paUnanticipatedHostError ); } else ENSURE_( snd_pcm_prepare( stream->playback.pcm ), paUnanticipatedHostError ); } if( stream->capture.pcm && !stream->pcmsSynced ) { ENSURE_( snd_pcm_prepare( stream->capture.pcm ), paUnanticipatedHostError ); /* For a blocking stream we want to start capture as well, since nothing will happen otherwise */ ENSURE_( snd_pcm_start( stream->capture.pcm ), paUnanticipatedHostError ); } end: return result; error: goto end; } /** Utility function for determining if pcms are in running state. * */ static int IsRunning( PaAlsaStream *stream ) { int result = 0; LockMutex( &stream->stateMtx ); if( stream->capture.pcm ) { snd_pcm_state_t capture_state = snd_pcm_state( stream->capture.pcm ); if( capture_state == SND_PCM_STATE_RUNNING || capture_state == SND_PCM_STATE_XRUN || capture_state == SND_PCM_STATE_DRAINING ) { result = 1; goto end; } } if( stream->playback.pcm ) { snd_pcm_state_t playback_state = snd_pcm_state( stream->playback.pcm ); if( playback_state == SND_PCM_STATE_RUNNING || playback_state == SND_PCM_STATE_XRUN || playback_state == SND_PCM_STATE_DRAINING ) { result = 1; goto end; } } end: ASSERT_CALL_( UnlockMutex( &stream->stateMtx ), paNoError ); return result; } static PaError StartStream( PaStream *s ) { PaError result = paNoError; PaAlsaStream *stream = (PaAlsaStream*)s; int streamStarted = 0; /* So we can know wether we need to take the stream down */ /* Ready the processor */ PaUtil_ResetBufferProcessor( &stream->bufferProcessor ); /* Set now, so we can test for activity further down */ stream->isActive = 1; if( stream->callbackMode ) { int res = 0; PaTime pt = PaUtil_GetTime(); struct timespec ts; PA_ENSURE( CreateCallbackThread( &stream->threading, &CallbackThreadFunc, stream ) ); streamStarted = 1; /* Wait for stream to be started */ ts.tv_sec = (time_t) floor( pt + 1 ); ts.tv_nsec = (long) ((pt - floor( pt )) * 1000000000); /* Since we'll be holding a lock on the startMtx (when not waiting on the condition), IsRunning won't be checking * stream state at the same time as the callback thread affects it. We also check IsStreamActive, in the unlikely * case the callback thread exits in the meantime (the stream will be considered inactive after the thread exits) */ PA_ENSURE( LockMutex( &stream->startMtx ) ); /* Due to possible spurious wakeups, we enclose in a loop */ while( !IsRunning( stream ) && IsStreamActive( s ) && !res ) { res = pthread_cond_timedwait( &stream->startCond, &stream->startMtx, &ts ); } PA_ENSURE( UnlockMutex( &stream->startMtx ) ); PA_UNLESS( !res || res == ETIMEDOUT, paInternalError ); PA_DEBUG(( "%s: Waited for %g seconds for stream to start\n", __FUNCTION__, PaUtil_GetTime() - pt )); if( res == ETIMEDOUT ) { PA_ENSURE( paTimedOut ); } } else { PA_ENSURE( AlsaStart( stream, 0 ) ); streamStarted = 1; } end: return result; error: if( streamStarted ) AbortStream( stream ); stream->isActive = 0; goto end; } static PaError AlsaStop( PaAlsaStream *stream, int abort ) { PaError result = paNoError; if( abort ) { if( stream->playback.pcm ) { ENSURE_( snd_pcm_drop( stream->playback.pcm ), paUnanticipatedHostError ); } if( stream->capture.pcm && !stream->pcmsSynced ) { ENSURE_( snd_pcm_drop( stream->capture.pcm ), paUnanticipatedHostError ); } PA_DEBUG(( "%s: Dropped frames\n", __FUNCTION__ )); } else { if( stream->playback.pcm ) { ENSURE_( snd_pcm_nonblock( stream->playback.pcm, 0 ), paUnanticipatedHostError ); if( snd_pcm_drain( stream->playback.pcm ) < 0 ) { PA_DEBUG(( "%s: Draining playback handle failed!\n", __FUNCTION__ )); } } if( stream->capture.pcm && !stream->pcmsSynced ) { /* We don't need to retrieve any remaining frames */ if( snd_pcm_drop( stream->capture.pcm ) < 0 ) { PA_DEBUG(( "%s: Draining capture handle failed!\n", __FUNCTION__ )); } } } end: return result; error: goto end; } /** Stop or abort stream. * * If a stream is in callback mode we will have to inspect wether the background thread has * finished, or we will have to take it out. In either case we join the thread before * returning. In blocking mode, we simply tell ALSA to stop abruptly (abort) or finish * buffers (drain) * * Stream will be considered inactive (!PaAlsaStream::isActive) after a call to this function */ static PaError RealStop( PaAlsaStream *stream, int abort ) { PaError result = paNoError; /* First deal with the callback thread, cancelling and/or joining * it if necessary */ if( stream->callbackMode ) { PaError threadRes, watchdogRes; stream->callbackAbort = abort; if( !abort ) { PA_DEBUG(( "Stopping callback\n" )); stream->callbackStop = 1; } PA_ENSURE( KillCallbackThread( &stream->threading, !abort, &threadRes, &watchdogRes ) ); if( threadRes != paNoError ) PA_DEBUG(( "Callback thread returned: %d\n", threadRes )); if( watchdogRes != paNoError ) PA_DEBUG(( "Watchdog thread returned: %d\n", watchdogRes )); stream->callbackStop = 0; /* The deed is done */ stream->callback_finished = 0; } else { PA_ENSURE( AlsaStop( stream, abort ) ); } stream->isActive = 0; end: return result; error: goto end; } static PaError StopStream( PaStream *s ) { return RealStop( (PaAlsaStream *) s, 0 ); } static PaError AbortStream( PaStream *s ) { return RealStop( (PaAlsaStream * ) s, 1 ); } /** The stream is considered stopped before StartStream, or AFTER a call to Abort/StopStream (callback * returning !paContinue is not considered) * */ static PaError IsStreamStopped( PaStream *s ) { PaAlsaStream *stream = (PaAlsaStream *)s; /* callback_finished indicates we need to join callback thread (ie. in Abort/StopStream) */ return !IsStreamActive( s ) && !stream->callback_finished; } static PaError IsStreamActive( PaStream *s ) { PaAlsaStream *stream = (PaAlsaStream*)s; return stream->isActive; } static PaTime GetStreamTime( PaStream *s ) { PaAlsaStream *stream = (PaAlsaStream*)s; snd_timestamp_t timestamp; snd_pcm_status_t *status; snd_pcm_status_alloca( &status ); /* TODO: what if we have both? does it really matter? */ /* TODO: if running in callback mode, this will mean * libasound routines are being called from multiple threads. * need to verify that libasound is thread-safe. */ if( stream->capture.pcm ) { snd_pcm_status( stream->capture.pcm, status ); } else if( stream->playback.pcm ) { snd_pcm_status( stream->playback.pcm, status ); } snd_pcm_status_get_tstamp( status, ×tamp ); return timestamp.tv_sec + (PaTime)timestamp.tv_usec / 1000000.0; } static double GetStreamCpuLoad( PaStream* s ) { PaAlsaStream *stream = (PaAlsaStream*)s; return PaUtil_GetCpuLoad( &stream->cpuLoadMeasurer ); } static int SetApproximateSampleRate( snd_pcm_t *pcm, snd_pcm_hw_params_t *hwParams, double sampleRate ) { unsigned long approx = (unsigned long) sampleRate; int dir = 0; double fraction = sampleRate - approx; assert( pcm && hwParams ); if( fraction > 0.0 ) { if( fraction > 0.5 ) { ++approx; dir = -1; } else dir = 1; } return snd_pcm_hw_params_set_rate( pcm, hwParams, approx, dir ); } /* Return exact sample rate in param sampleRate */ static int GetExactSampleRate( snd_pcm_hw_params_t *hwParams, double *sampleRate ) { unsigned int num, den; int err; assert( hwParams ); err = snd_pcm_hw_params_get_rate_numden( hwParams, &num, &den ); *sampleRate = (double) num / den; return err; } /* Utility functions for blocking/callback interfaces */ /* Atomic restart of stream (we don't want the intermediate state visible) */ static PaError AlsaRestart( PaAlsaStream *stream ) { PaError result = paNoError; PA_ENSURE( LockMutex( &stream->stateMtx ) ); PA_ENSURE( AlsaStop( stream, 0 ) ); PA_ENSURE( AlsaStart( stream, 0 ) ); PA_DEBUG(( "%s: Restarted audio\n", __FUNCTION__ )); error: PA_ENSURE( UnlockMutex( &stream->stateMtx ) ); return result; } /** Recover from xrun state. * */ static PaError PaAlsaStream_HandleXrun( PaAlsaStream *self ) { PaError result = paNoError; snd_pcm_status_t *st; PaTime now = PaUtil_GetTime(); snd_timestamp_t t; snd_pcm_status_alloca( &st ); if( self->playback.pcm ) { snd_pcm_status( self->playback.pcm, st ); if( snd_pcm_status_get_state( st ) == SND_PCM_STATE_XRUN ) { snd_pcm_status_get_trigger_tstamp( st, &t ); self->underrun = now * 1000 - ((PaTime) t.tv_sec * 1000 + (PaTime) t.tv_usec / 1000); } } if( self->capture.pcm ) { snd_pcm_status( self->capture.pcm, st ); if( snd_pcm_status_get_state( st ) == SND_PCM_STATE_XRUN ) { snd_pcm_status_get_trigger_tstamp( st, &t ); self->overrun = now * 1000 - ((PaTime) t.tv_sec * 1000 + (PaTime) t.tv_usec / 1000); } } PA_ENSURE( AlsaRestart( self ) ); end: return result; error: goto end; } /** Decide if we should continue polling for specified direction, eventually adjust the poll timeout. * */ static PaError ContinuePoll( const PaAlsaStream *stream, StreamDirection streamDir, int *pollTimeout, int *continuePoll ) { PaError result = paNoError; snd_pcm_sframes_t delay, margin; int err; const PaAlsaStreamComponent *component = NULL, *otherComponent = NULL; *continuePoll = 1; if( StreamDirection_In == streamDir ) { component = &stream->capture; otherComponent = &stream->playback; } else { component = &stream->playback; otherComponent = &stream->capture; } /* ALSA docs say that negative delay should indicate xrun, but in my experience snd_pcm_delay returns -EPIPE */ if( (err = snd_pcm_delay( otherComponent->pcm, &delay )) < 0 ) { if( err == -EPIPE ) { /* Xrun */ *continuePoll = 0; goto error; } ENSURE_( err, paUnanticipatedHostError ); } if( StreamDirection_Out == streamDir ) { /* Number of eligible frames before capture overrun */ delay = otherComponent->bufferSize - delay; } margin = delay - otherComponent->framesPerBuffer / 2; if( margin < 0 ) { PA_DEBUG(( "%s: Stopping poll for %s\n", __FUNCTION__, StreamDirection_In == streamDir ? "capture" : "playback" )); *continuePoll = 0; } else if( margin < otherComponent->framesPerBuffer ) { *pollTimeout = CalculatePollTimeout( stream, margin ); PA_DEBUG(( "%s: Trying to poll again for %s frames, pollTimeout: %d\n", __FUNCTION__, StreamDirection_In == streamDir ? "capture" : "playback", *pollTimeout )); } error: return result; } /* Callback interface */ static void OnExit( void *data ) { PaAlsaStream *stream = (PaAlsaStream *) data; assert( data ); PaUtil_ResetCpuLoadMeasurer( &stream->cpuLoadMeasurer ); stream->callback_finished = 1; /* Let the outside world know stream was stopped in callback */ PA_DEBUG(( "%s: Stopping ALSA handles\n", __FUNCTION__ )); AlsaStop( stream, stream->callbackAbort ); stream->callbackAbort = 0; /* Clear state */ PA_DEBUG(( "%s: Stoppage\n", __FUNCTION__ )); /* Eventually notify user all buffers have played */ if( stream->streamRepresentation.streamFinishedCallback ) stream->streamRepresentation.streamFinishedCallback( stream->streamRepresentation.userData ); stream->isActive = 0; } static void CalculateTimeInfo( PaAlsaStream *stream, PaStreamCallbackTimeInfo *timeInfo ) { snd_pcm_status_t *capture_status, *playback_status; snd_timestamp_t capture_timestamp, playback_timestamp; PaTime capture_time = 0., playback_time = 0.; snd_pcm_status_alloca( &capture_status ); snd_pcm_status_alloca( &playback_status ); if( stream->capture.pcm ) { snd_pcm_sframes_t capture_delay; snd_pcm_status( stream->capture.pcm, capture_status ); snd_pcm_status_get_tstamp( capture_status, &capture_timestamp ); capture_time = capture_timestamp.tv_sec + ((PaTime)capture_timestamp.tv_usec / 1000000.0); timeInfo->currentTime = capture_time; capture_delay = snd_pcm_status_get_delay( capture_status ); timeInfo->inputBufferAdcTime = timeInfo->currentTime - (PaTime)capture_delay / stream->streamRepresentation.streamInfo.sampleRate; } if( stream->playback.pcm ) { snd_pcm_sframes_t playback_delay; snd_pcm_status( stream->playback.pcm, playback_status ); snd_pcm_status_get_tstamp( playback_status, &playback_timestamp ); playback_time = playback_timestamp.tv_sec + ((PaTime)playback_timestamp.tv_usec / 1000000.0); if( stream->capture.pcm ) /* Full duplex */ { /* Hmm, we have both a playback and a capture timestamp. * Hopefully they are the same... */ if( fabs( capture_time - playback_time ) > 0.01 ) PA_DEBUG(("Capture time and playback time differ by %f\n", fabs(capture_time-playback_time))); } else timeInfo->currentTime = playback_time; playback_delay = snd_pcm_status_get_delay( playback_status ); timeInfo->outputBufferDacTime = timeInfo->currentTime + (PaTime)playback_delay / stream->streamRepresentation.streamInfo.sampleRate; } } /** Called after buffer processing is finished. * * A number of mmapped frames is committed, it is possible that an xrun has occurred in the meantime. * * @param numFrames The number of frames that has been processed * @param xrun Return whether an xrun has occurred */ static PaError PaAlsaStreamComponent_EndProcessing( PaAlsaStreamComponent *self, unsigned long numFrames, int *xrun ) { PaError result = paNoError; int res; /* @concern FullDuplex It is possible that only one direction is marked ready after polling, and processed * afterwards */ if( !self->ready ) goto end; res = snd_pcm_mmap_commit( self->pcm, self->offset, numFrames ); if( res == -EPIPE || res == -ESTRPIPE ) { *xrun = 1; } else { ENSURE_( res, paUnanticipatedHostError ); } end: error: return result; } /* Extract buffer from channel area */ static unsigned char *ExtractAddress( const snd_pcm_channel_area_t *area, snd_pcm_uframes_t offset ) { return (unsigned char *) area->addr + (area->first + offset * area->step) / 8; } /** Do necessary adaption between user and host channels. * @concern ChannelAdaption Adapting between user and host channels can involve silencing unused channels and duplicating mono information if host outputs come in pairs. */ static PaError PaAlsaStreamComponent_DoChannelAdaption( PaAlsaStreamComponent *self, PaUtilBufferProcessor *bp, int numFrames ) { PaError result = paNoError; unsigned char *p; int i; int unusedChans = self->numHostChannels - self->numUserChannels; unsigned char *src, *dst; int convertMono = (self->numHostChannels % 2) == 0 && (self->numUserChannels % 2) != 0; assert( StreamDirection_Out == self->streamDir ); if( self->hostInterleaved ) { int swidth = snd_pcm_format_size( self->nativeFormat, 1 ); unsigned char *buffer = ExtractAddress( self->channelAreas, self->offset ); /* Start after the last user channel */ p = buffer + self->numUserChannels * swidth; if( convertMono ) { /* Convert the last user channel into stereo pair */ src = buffer + (self->numUserChannels - 1) * swidth; for( i = 0; i < numFrames; ++i ) { dst = src + swidth; memcpy( dst, src, swidth ); src += self->numHostChannels * swidth; } /* Don't touch the channel we just wrote to */ p += swidth; --unusedChans; } if( unusedChans > 0 ) { /* Silence unused output channels */ for( i = 0; i < numFrames; ++i ) { memset( p, 0, swidth * unusedChans ); p += self->numHostChannels * swidth; } } } else { /* We extract the last user channel */ if( convertMono ) { ENSURE_( snd_pcm_area_copy( self->channelAreas + self->numUserChannels, self->offset, self->channelAreas + (self->numUserChannels - 1), self->offset, numFrames, self->nativeFormat ), paUnanticipatedHostError ); --unusedChans; } if( unusedChans > 0 ) { snd_pcm_areas_silence( self->channelAreas + (self->numHostChannels - unusedChans), self->offset, unusedChans, numFrames, self->nativeFormat ); } } error: return result; } static PaError PaAlsaStream_EndProcessing( PaAlsaStream *self, unsigned long numFrames, int *xrunOccurred ) { PaError result = paNoError; int xrun = 0; if( self->capture.pcm ) { PA_ENSURE( PaAlsaStreamComponent_EndProcessing( &self->capture, numFrames, &xrun ) ); } if( self->playback.pcm ) { if( self->playback.numHostChannels > self->playback.numUserChannels ) PA_ENSURE( PaAlsaStreamComponent_DoChannelAdaption( &self->playback, &self->bufferProcessor, numFrames ) ); PA_ENSURE( PaAlsaStreamComponent_EndProcessing( &self->playback, numFrames, &xrun ) ); } error: *xrunOccurred = xrun; return result; } /** Update the number of available frames. * */ static PaError PaAlsaStreamComponent_GetAvailableFrames( PaAlsaStreamComponent *self, unsigned long *numFrames, int *xrunOccurred ) { PaError result = paNoError; snd_pcm_sframes_t framesAvail = snd_pcm_avail_update( self->pcm ); *xrunOccurred = 0; if( -EPIPE == framesAvail ) { *xrunOccurred = 1; framesAvail = 0; } else ENSURE_( framesAvail, paUnanticipatedHostError ); *numFrames = framesAvail; error: return result; } /** Fill in pollfd objects. */ static PaError PaAlsaStreamComponent_BeginPolling( PaAlsaStreamComponent* self, struct pollfd* pfds ) { PaError result = paNoError; int ret = snd_pcm_poll_descriptors( self->pcm, pfds, self->nfds ); (void)ret; /* Prevent unused variable warning if asserts are turned off */ assert( ret == self->nfds ); self->ready = 0; return result; } /** Examine results from poll(). * * @param pfds pollfds to inspect * @param shouldPoll Should we continue to poll * @param xrun Has an xrun occurred */ static PaError PaAlsaStreamComponent_EndPolling( PaAlsaStreamComponent* self, struct pollfd* pfds, int* shouldPoll, int* xrun ) { PaError result = paNoError; unsigned short revents; ENSURE_( snd_pcm_poll_descriptors_revents( self->pcm, pfds, self->nfds, &revents ), paUnanticipatedHostError ); if( revents != 0 ) { if( revents & POLLERR ) { *xrun = 1; } else self->ready = 1; *shouldPoll = 0; } error: return result; } /** Return the number of available frames for this stream. * * @concern FullDuplex The minimum available for the two directions is calculated, it might be desirable to ignore * one direction however (not marked ready from poll), so this is controlled by queryCapture and queryPlayback. * * @param queryCapture Check available for capture * @param queryPlayback Check available for playback * @param available The returned number of frames * @param xrunOccurred Return whether an xrun has occurred */ static PaError PaAlsaStream_GetAvailableFrames( PaAlsaStream *self, int queryCapture, int queryPlayback, unsigned long *available, int *xrunOccurred ) { PaError result = paNoError; unsigned long captureFrames, playbackFrames; *xrunOccurred = 0; assert( queryCapture || queryPlayback ); if( queryCapture ) { assert( self->capture.pcm ); PA_ENSURE( PaAlsaStreamComponent_GetAvailableFrames( &self->capture, &captureFrames, xrunOccurred ) ); if( *xrunOccurred ) goto end; } if( queryPlayback ) { assert( self->playback.pcm ); PA_ENSURE( PaAlsaStreamComponent_GetAvailableFrames( &self->playback, &playbackFrames, xrunOccurred ) ); if( *xrunOccurred ) goto end; } if( queryCapture && queryPlayback ) { *available = PA_MIN( captureFrames, playbackFrames ); /*PA_DEBUG(("capture: %lu, playback: %lu, combined: %lu\n", captureFrames, playbackFrames, *available));*/ } else if( queryCapture ) { *available = captureFrames; } else { *available = playbackFrames; } end: error: return result; } /** Wait for and report available buffer space from ALSA. * * Unless ALSA reports a minimum of frames available for I/O, we poll the ALSA filedescriptors for more. * Both of these operations can uncover xrun conditions. * * @concern Xruns Both polling and querying available frames can report an xrun condition. * * @param framesAvail Return the number of available frames * @param xrunOccurred Return whether an xrun has occurred */ static PaError PaAlsaStream_WaitForFrames( PaAlsaStream *self, unsigned long *framesAvail, int *xrunOccurred ) { PaError result = paNoError; int pollPlayback = self->playback.pcm != NULL, pollCapture = self->capture.pcm != NULL; int pollTimeout = self->pollTimeout; int xrun = 0; assert( self ); assert( framesAvail ); if( !self->callbackMode ) { /* In blocking mode we will only wait if necessary */ PA_ENSURE( PaAlsaStream_GetAvailableFrames( self, self->capture.pcm != NULL, self->playback.pcm != NULL, framesAvail, &xrun ) ); if( xrun ) { goto end; } if( *framesAvail > 0 ) { /* Mark pcms ready from poll */ if( self->capture.pcm ) self->capture.ready = 1; if( self->playback.pcm ) self->playback.ready = 1; goto end; } } while( pollPlayback || pollCapture ) { int totalFds = 0; struct pollfd *capturePfds = NULL, *playbackPfds = NULL; pthread_testcancel(); if( pollCapture ) { capturePfds = self->pfds; PA_ENSURE( PaAlsaStreamComponent_BeginPolling( &self->capture, capturePfds ) ); totalFds += self->capture.nfds; } if( pollPlayback ) { playbackPfds = self->pfds + (self->capture.pcm ? self->capture.nfds : 0); PA_ENSURE( PaAlsaStreamComponent_BeginPolling( &self->playback, playbackPfds ) ); totalFds += self->playback.nfds; } if( poll( self->pfds, totalFds, pollTimeout ) < 0 ) { /* XXX: Depend on preprocessor condition? */ if( errno == EINTR ) { /* gdb */ continue; } /* TODO: Add macro for checking system calls */ PA_ENSURE( paInternalError ); } /* check the return status of our pfds */ if( pollCapture ) { PA_ENSURE( PaAlsaStreamComponent_EndPolling( &self->capture, capturePfds, &pollCapture, &xrun ) ); } if( pollPlayback ) { PA_ENSURE( PaAlsaStreamComponent_EndPolling( &self->playback, playbackPfds, &pollPlayback, &xrun ) ); } if( xrun ) { break; } /* @concern FullDuplex If only one of two pcms is ready we may want to compromise between the two. * If there is less than half a period's worth of samples left of frames in the other pcm's buffer we will * stop polling. */ if( self->capture.pcm && self->playback.pcm ) { if( pollCapture && !pollPlayback ) { PA_ENSURE( ContinuePoll( self, StreamDirection_In, &pollTimeout, &pollCapture ) ); } else if( pollPlayback && !pollCapture ) { PA_ENSURE( ContinuePoll( self, StreamDirection_Out, &pollTimeout, &pollPlayback ) ); } } } if( !xrun ) { /* Get the number of available frames for the pcms that are marked ready. * @concern FullDuplex If only one direction is marked ready (from poll), the number of frames available for * the other direction is returned. Output is normally preferred over capture however, so capture frames may be * discarded to avoid overrun unless paNeverDropInput is specified. */ int captureReady = self->capture.pcm ? self->capture.ready : 0, playbackReady = self->playback.pcm ? self->playback.ready : 0; PA_ENSURE( PaAlsaStream_GetAvailableFrames( self, captureReady, playbackReady, framesAvail, &xrun ) ); if( self->capture.pcm && self->playback.pcm ) { if( !self->playback.ready && !self->neverDropInput ) { /* Drop input, a period's worth */ assert( self->capture.ready ); PaAlsaStreamComponent_EndProcessing( &self->capture, PA_MIN( self->capture.framesPerBuffer, *framesAvail ), &xrun ); *framesAvail = 0; self->capture.ready = 0; } } else if( self->capture.pcm ) assert( self->capture.ready ); else assert( self->playback.ready ); } end: error: if( xrun ) { /* Recover from the xrun state */ PA_ENSURE( PaAlsaStream_HandleXrun( self ) ); *framesAvail = 0; } else { if( 0 != *framesAvail ) { /* If we're reporting frames eligible for processing, one of the handles better be ready */ PA_UNLESS( self->capture.ready || self->playback.ready, paInternalError ); } } *xrunOccurred = xrun; return result; } /** Register per-channel ALSA buffer information with buffer processor. * * Mmapped buffer space is acquired from ALSA, and registered with the buffer processor. Differences between the * number of host and user channels is taken into account. * * @param numFrames On entrance the number of requested frames, on exit the number of contiguously accessible frames. */ static PaError PaAlsaStreamComponent_RegisterChannels( PaAlsaStreamComponent *self, PaUtilBufferProcessor *bp, unsigned long *numFrames, int *xrun ) { PaError result = paNoError; const snd_pcm_channel_area_t *areas, *area; void (*setChannel)(PaUtilBufferProcessor *, unsigned int, void *, unsigned int) = StreamDirection_In == self->streamDir ? PaUtil_SetInputChannel : PaUtil_SetOutputChannel; unsigned char *buffer, *p; int i; unsigned long framesAvail; /* This _must_ be called before mmap_begin */ PA_ENSURE( PaAlsaStreamComponent_GetAvailableFrames( self, &framesAvail, xrun ) ); if( *xrun ) { *numFrames = 0; goto end; } ENSURE_( snd_pcm_mmap_begin( self->pcm, &areas, &self->offset, numFrames ), paUnanticipatedHostError ); if( self->hostInterleaved ) { int swidth = snd_pcm_format_size( self->nativeFormat, 1 ); p = buffer = ExtractAddress( areas, self->offset ); for( i = 0; i < self->numUserChannels; ++i ) { /* We're setting the channels up to userChannels, but the stride will be hostChannels samples */ setChannel( bp, i, p, self->numHostChannels ); p += swidth; } } else { for( i = 0; i < self->numUserChannels; ++i ) { area = areas + i; buffer = ExtractAddress( area, self->offset ); setChannel( bp, i, buffer, 1 ); } } /* @concern ChannelAdaption Buffer address is recorded so we can do some channel adaption later */ self->channelAreas = (snd_pcm_channel_area_t *)areas; end: error: return result; } /** Initiate buffer processing. * * ALSA buffers are registered with the PA buffer processor and the buffer size (in frames) set. * * @concern FullDuplex If both directions are being processed, the minimum amount of frames for the two directions is * calculated. * * @param numFrames On entrance the number of available frames, on exit the number of received frames * @param xrunOccurred Return whether an xrun has occurred */ static PaError PaAlsaStream_SetUpBuffers( PaAlsaStream *self, unsigned long *numFrames, int *xrunOccurred ) { PaError result = paNoError; unsigned long captureFrames = ULONG_MAX, playbackFrames = ULONG_MAX, commonFrames = 0; int xrun = 0; if( *xrunOccurred ) { *numFrames = 0; return result; } /* If we got here at least one of the pcm's should be marked ready */ PA_UNLESS( self->capture.ready || self->playback.ready, paInternalError ); /* Extract per-channel ALSA buffer pointers and register them with the buffer processor. * It is possible that a direction is not marked ready however, because it is out of sync with the other. */ if( self->capture.pcm && self->capture.ready ) { captureFrames = *numFrames; PA_ENSURE( PaAlsaStreamComponent_RegisterChannels( &self->capture, &self->bufferProcessor, &captureFrames, &xrun ) ); } if( self->playback.pcm && self->playback.ready ) { playbackFrames = *numFrames; PA_ENSURE( PaAlsaStreamComponent_RegisterChannels( &self->playback, &self->bufferProcessor, &playbackFrames, &xrun ) ); } if( xrun ) { /* Nothing more to do */ assert( 0 == commonFrames ); goto end; } commonFrames = PA_MIN( captureFrames, playbackFrames ); /* assert( commonFrames <= *numFrames ); */ if( commonFrames > *numFrames ) { /* Hmmm ... how come there are more frames available than we requested!? Blah. */ PA_DEBUG(( "%s: Common available frames are reported to be more than number requested: %lu, %lu, callbackMode: %d\n", __FUNCTION__, commonFrames, *numFrames, self->callbackMode )); if( self->capture.pcm ) { PA_DEBUG(( "%s: captureFrames: %lu, capture.ready: %d\n", __FUNCTION__, captureFrames, self->capture.ready )); } if( self->playback.pcm ) { PA_DEBUG(( "%s: playbackFrames: %lu, playback.ready: %d\n", __FUNCTION__, playbackFrames, self->playback.ready )); } commonFrames = 0; goto end; } /* Inform PortAudio of the number of frames we got. * @concern FullDuplex We might be experiencing underflow in either end; if its an input underflow, we go on * with output. If its output underflow however, depending on the paNeverDropInput flag, we may want to simply * discard the excess input or call the callback with paOutputOverflow flagged. */ if( self->capture.pcm ) { if( self->capture.ready ) { PaUtil_SetInputFrameCount( &self->bufferProcessor, commonFrames ); } else { /* We have input underflow */ PaUtil_SetNoInput( &self->bufferProcessor ); } } if( self->playback.pcm ) { if( self->playback.ready ) { PaUtil_SetOutputFrameCount( &self->bufferProcessor, commonFrames ); } else { /* We have output underflow, but keeping input data (paNeverDropInput) */ assert( self->neverDropInput ); assert( self->capture.pcm != NULL ); PA_DEBUG(( "%s: Setting output buffers to NULL\n", __FUNCTION__ )); PaUtil_SetNoOutput( &self->bufferProcessor ); } } end: *numFrames = commonFrames; error: if( xrun ) { PA_ENSURE( PaAlsaStream_HandleXrun( self ) ); *numFrames = 0; } *xrunOccurred = xrun; return result; } /** Callback thread's function. * * Roughly, the workflow can be described in the following way: The number of available frames that can be processed * directly is obtained from ALSA, we then request as much directly accessible memory as possible within this amount * from ALSA. The buffer memory is registered with the PA buffer processor and processing is carried out with * PaUtil_EndBufferProcessing. Finally, the number of processed frames is reported to ALSA. The processing can * happen in several iterations untill we have consumed the known number of available frames (or an xrun is detected). */ static void *CallbackThreadFunc( void *userData ) { PaError result = paNoError, *pres = NULL; PaAlsaStream *stream = (PaAlsaStream*) userData; PaStreamCallbackTimeInfo timeInfo = {0, 0, 0}; snd_pcm_sframes_t startThreshold = 0; int callbackResult = paContinue; PaStreamCallbackFlags cbFlags = 0; /* We might want to keep state across iterations */ int streamStarted = 0; assert( stream ); callbackThread_ = pthread_self(); /* Execute OnExit when exiting */ pthread_cleanup_push( &OnExit, stream ); /* Not implemented */ assert( !stream->primeBuffers ); /* @concern StreamStart If the output is being primed the output pcm needs to be prepared, otherwise the * stream is started immediately. The latter involves signaling the waiting main thread. */ if( stream->primeBuffers ) { snd_pcm_sframes_t avail; if( stream->playback.pcm ) ENSURE_( snd_pcm_prepare( stream->playback.pcm ), paUnanticipatedHostError ); if( stream->capture.pcm && !stream->pcmsSynced ) ENSURE_( snd_pcm_prepare( stream->capture.pcm ), paUnanticipatedHostError ); /* We can't be certain that the whole ring buffer is available for priming, but there should be * at least one period */ avail = snd_pcm_avail_update( stream->playback.pcm ); startThreshold = avail - (avail % stream->playback.framesPerBuffer); assert( startThreshold >= stream->playback.framesPerBuffer ); } else { PA_ENSURE( LockMutex( &stream->startMtx ) ); PA_ENSURE( AlsaStart( stream, 0 ) ); /* Buffer will be zeroed */ ENSURE_SYSTEM_( pthread_cond_signal( &stream->startCond ), 0 ); PA_ENSURE( UnlockMutex( &stream->startMtx ) ); streamStarted = 1; } while( 1 ) { unsigned long framesAvail, framesGot; int xrun = 0; pthread_testcancel(); /* @concern StreamStop if the main thread has requested a stop and the stream has not been effectively * stopped we signal this condition by modifying callbackResult (we'll want to flush buffered output). */ if( stream->callbackStop && paContinue == callbackResult ) { PA_DEBUG(( "Setting callbackResult to paComplete\n" )); callbackResult = paComplete; } if( paContinue != callbackResult ) { stream->callbackAbort = (paAbort == callbackResult); if( stream->callbackAbort || /** @concern BlockAdaption: Go on if adaption buffers are empty */ PaUtil_IsBufferProcessorOutputEmpty( &stream->bufferProcessor ) ) goto end; PA_DEBUG(( "%s: Flushing buffer processor\n", __FUNCTION__ )); /* There is still buffered output that needs to be processed */ } /* Wait for data to become available, this comes down to polling the ALSA file descriptors untill we have * a number of available frames. */ PA_ENSURE( PaAlsaStream_WaitForFrames( stream, &framesAvail, &xrun ) ); if( xrun ) { assert( 0 == framesAvail ); continue; /* XXX: Report xruns to the user? A situation is conceivable where the callback is never invoked due * to constant xruns, it might be desirable to notify the user of this. */ } /* Consume buffer space. Once we have a number of frames available for consumption we must retrieve the * mmapped buffers from ALSA, this is contiguously accessible memory however, so we may receive smaller * portions at a time than is available as a whole. Therefore we should be prepared to process several * chunks successively. The buffers are passed to the PA buffer processor. */ while( framesAvail > 0 ) { xrun = 0; pthread_testcancel(); /** @concern Xruns Under/overflows are to be reported to the callback */ if( stream->underrun > 0.0 ) { cbFlags |= paOutputUnderflow; stream->underrun = 0.0; } if( stream->overrun > 0.0 ) { cbFlags |= paInputOverflow; stream->overrun = 0.0; } if( stream->capture.pcm && stream->playback.pcm ) { /** @concern FullDuplex It's possible that only one direction is being processed to avoid an * under- or overflow, this should be reported correspondingly */ if( !stream->capture.ready ) { cbFlags |= paInputUnderflow; PA_DEBUG(( "%s: Input underflow\n", __FUNCTION__ )); } else if( !stream->playback.ready ) { cbFlags |= paOutputOverflow; PA_DEBUG(( "%s: Output overflow\n", __FUNCTION__ )); } } CallbackUpdate( &stream->threading ); CalculateTimeInfo( stream, &timeInfo ); PaUtil_BeginBufferProcessing( &stream->bufferProcessor, &timeInfo, cbFlags ); cbFlags = 0; /* CPU load measurement should include processing activivity external to the stream callback */ PaUtil_BeginCpuLoadMeasurement( &stream->cpuLoadMeasurer ); framesGot = framesAvail; PA_ENSURE( PaAlsaStream_SetUpBuffers( stream, &framesGot, &xrun ) ); /* Check the host buffer size against the buffer processor configuration */ if( stream->bufferProcessor.hostBufferSizeMode == paUtilFixedHostBufferSize ) { /* We've committed to a fixed host buffer size, stick to that */ framesGot = framesGot >= stream->maxFramesPerHostBuffer ? stream->maxFramesPerHostBuffer : 0; } else { /* We've committed to an upper bound on the size of host buffers */ assert( stream->bufferProcessor.hostBufferSizeMode == paUtilBoundedHostBufferSize ); framesGot = PA_MIN( framesGot, stream->maxFramesPerHostBuffer ); } framesAvail -= framesGot; if( framesGot > 0 ) { assert( !xrun ); PaUtil_EndBufferProcessing( &stream->bufferProcessor, &callbackResult ); PA_ENSURE( PaAlsaStream_EndProcessing( stream, framesGot, &xrun ) ); } PaUtil_EndCpuLoadMeasurement( &stream->cpuLoadMeasurer, framesGot ); if( framesGot == 0 ) { if( !xrun ) { PA_DEBUG(( "%s: Received less frames than reported from ALSA, framesAvail: %lu\n", __FUNCTION__, framesAvail )); } /* Go back to polling for more frames */ break; } if( paContinue != callbackResult ) break; } } /* Match pthread_cleanup_push */ pthread_cleanup_pop( 1 ); end: PA_DEBUG(( "%s: Thread %d exiting\n ", __FUNCTION__, pthread_self() )); pthread_exit( pres ); error: /* Pass on error code */ pres = malloc( sizeof (PaError) ); *pres = result; goto end; } /* Blocking interface */ static PaError ReadStream( PaStream* s, void *buffer, unsigned long frames ) { PaError result = paNoError; PaAlsaStream *stream = (PaAlsaStream*)s; unsigned long framesGot, framesAvail; void *userBuffer; snd_pcm_t *save = stream->playback.pcm; assert( stream ); PA_UNLESS( stream->capture.pcm, paCanNotReadFromAnOutputOnlyStream ); /* Disregard playback */ stream->playback.pcm = NULL; if( stream->overrun > 0. ) { result = paInputOverflowed; stream->overrun = 0.0; } if( stream->capture.userInterleaved ) { userBuffer = buffer; } else { /* Copy channels into local array */ userBuffer = stream->capture.userBuffers; memcpy( userBuffer, buffer, sizeof (void *) * stream->capture.numUserChannels ); } /* Start stream if in prepared state */ if( snd_pcm_state( stream->capture.pcm ) == SND_PCM_STATE_PREPARED ) { ENSURE_( snd_pcm_start( stream->capture.pcm ), paUnanticipatedHostError ); } while( frames > 0 ) { int xrun = 0; PA_ENSURE( PaAlsaStream_WaitForFrames( stream, &framesAvail, &xrun ) ); framesGot = PA_MIN( framesAvail, frames ); PA_ENSURE( PaAlsaStream_SetUpBuffers( stream, &framesGot, &xrun ) ); if( framesGot > 0 ) { framesGot = PaUtil_CopyInput( &stream->bufferProcessor, &userBuffer, framesGot ); PA_ENSURE( PaAlsaStream_EndProcessing( stream, framesGot, &xrun ) ); frames -= framesGot; } } end: stream->playback.pcm = save; return result; error: goto end; } static PaError WriteStream( PaStream* s, const void *buffer, unsigned long frames ) { PaError result = paNoError; signed long err; PaAlsaStream *stream = (PaAlsaStream*)s; snd_pcm_uframes_t framesGot, framesAvail; const void *userBuffer; snd_pcm_t *save = stream->capture.pcm; assert( stream ); PA_UNLESS( stream->playback.pcm, paCanNotWriteToAnInputOnlyStream ); /* Disregard capture */ stream->capture.pcm = NULL; if( stream->underrun > 0. ) { result = paOutputUnderflowed; stream->underrun = 0.0; } if( stream->playback.userInterleaved ) userBuffer = buffer; else /* Copy channels into local array */ { userBuffer = stream->playback.userBuffers; memcpy( (void *)userBuffer, buffer, sizeof (void *) * stream->playback.numUserChannels ); } while( frames > 0 ) { int xrun = 0; snd_pcm_uframes_t hwAvail; PA_ENSURE( PaAlsaStream_WaitForFrames( stream, &framesAvail, &xrun ) ); framesGot = PA_MIN( framesAvail, frames ); PA_ENSURE( PaAlsaStream_SetUpBuffers( stream, &framesGot, &xrun ) ); if( framesGot > 0 ) { framesGot = PaUtil_CopyOutput( &stream->bufferProcessor, &userBuffer, framesGot ); PA_ENSURE( PaAlsaStream_EndProcessing( stream, framesGot, &xrun ) ); frames -= framesGot; } /* Start stream after one period of samples worth */ /* Frames residing in buffer */ PA_ENSURE( err = GetStreamWriteAvailable( stream ) ); framesAvail = err; hwAvail = stream->playback.bufferSize - framesAvail; if( snd_pcm_state( stream->playback.pcm ) == SND_PCM_STATE_PREPARED && hwAvail >= stream->playback.framesPerBuffer ) { ENSURE_( snd_pcm_start( stream->playback.pcm ), paUnanticipatedHostError ); } } end: stream->capture.pcm = save; return result; error: goto end; } /* Return frames available for reading. In the event of an overflow, the capture pcm will be restarted */ static signed long GetStreamReadAvailable( PaStream* s ) { PaError result = paNoError; PaAlsaStream *stream = (PaAlsaStream*)s; unsigned long avail; int xrun; PA_ENSURE( PaAlsaStreamComponent_GetAvailableFrames( &stream->capture, &avail, &xrun ) ); if( xrun ) { PA_ENSURE( PaAlsaStream_HandleXrun( stream ) ); PA_ENSURE( PaAlsaStreamComponent_GetAvailableFrames( &stream->capture, &avail, &xrun ) ); if( xrun ) PA_ENSURE( paInputOverflowed ); } return (signed long)avail; error: return result; } static signed long GetStreamWriteAvailable( PaStream* s ) { PaError result = paNoError; PaAlsaStream *stream = (PaAlsaStream*)s; unsigned long avail; int xrun; PA_ENSURE( PaAlsaStreamComponent_GetAvailableFrames( &stream->playback, &avail, &xrun ) ); if( xrun ) { snd_pcm_sframes_t savail; PA_ENSURE( PaAlsaStream_HandleXrun( stream ) ); savail = snd_pcm_avail_update( stream->playback.pcm ); /* savail should not contain -EPIPE now, since PaAlsaStream_HandleXrun will only prepare the pcm */ ENSURE_( savail, paUnanticipatedHostError ); avail = (unsigned long) savail; } return (signed long)avail; error: return result; } /* Extensions */ /* Initialize host api specific structure */ void PaAlsa_InitializeStreamInfo( PaAlsaStreamInfo *info ) { info->size = sizeof (PaAlsaStreamInfo); info->hostApiType = paALSA; info->version = 1; info->deviceString = NULL; } void PaAlsa_EnableRealtimeScheduling( PaStream *s, int enable ) { PaAlsaStream *stream = (PaAlsaStream *) s; stream->threading.rtSched = enable; } void PaAlsa_EnableWatchdog( PaStream *s, int enable ) { PaAlsaStream *stream = (PaAlsaStream *) s; stream->threading.useWatchdog = enable; }