mirror of
https://github.com/dj0abr/SSB_HighSpeed_Modem.git
synced 2024-11-22 12:19:49 -05:00
246 lines
6.6 KiB
C
246 lines
6.6 KiB
C
/*
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* High Speed modem to transfer data in a 2,7kHz SSB channel
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* =========================================================
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* Author: DJ0ABR
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*
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* (c) DJ0ABR
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* www.dj0abr.de
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* audio.c ... functions to handle audio in/out via a soundcard
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* uses the "BASS" library
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*
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* captures samples from the sound card.
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* Samples are 32-bit floats in a range of -1 to +1
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* get these samples from the thread safe fifo: cap_read_fifo(&floatvariable)
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*
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* plays samples to the sound card
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* Samples are 32-bit floats in a range of -1 to +1
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* play the samples by calling the thread save function: pb_write_fifo(floatsample)
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*
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*/
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#include "qo100modem.h"
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//BOOL CALLBACK RecordingCallback(HRECORD handle, const void *buffer, DWORD length, void *user);
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DWORD CALLBACK WriteStream(HSTREAM handle, float *buffer, DWORD length, void *user);
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int pb_read_fifo(float *data, int elements);
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void close_audio();
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#define CHANNELS 1 // no of channels used
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HRECORD rchan = 0; // recording channel
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BASS_INFO info;
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HSTREAM stream = 0;
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int init_audio()
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{
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close_audio();
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printf("init audio, caprate:%d\n",caprate);
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// check the correct BASS was loaded
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if (HIWORD(BASS_GetVersion()) != BASSVERSION)
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{
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printf("An incorrect version of BASS was loaded\n");
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return -1;
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}
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/*
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// initalize default recording device
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if (!BASS_RecordInit(-1))
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{
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printf("Can't initialize recording device\n");
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return -1;
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}
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*/
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// initialize default output device
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if (!BASS_Init(-1, caprate, 0, NULL, NULL))
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{
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printf("Can't initialize output device\n");
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return -1;
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}
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/*
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// set capture callback
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rchan = BASS_RecordStart(caprate, CHANNELS, BASS_SAMPLE_FLOAT, RecordingCallback, 0);
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if (!rchan) {
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printf("Can't start capturing\n");
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return -1;
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}
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*/
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// set play callback
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BASS_GetInfo(&info);
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stream = BASS_StreamCreate(info.freq, CHANNELS, BASS_SAMPLE_FLOAT, (STREAMPROC*)WriteStream, 0); // sample: 32 bit float
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BASS_ChannelSetAttribute(stream, BASS_ATTRIB_BUFFER, 0); // no buffering for minimum latency
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BASS_ChannelPlay(stream, FALSE); // start it
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return 0;
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}
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void close_audio()
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{
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if(stream != 0)
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{
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//BASS_RecordFree();
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int r = BASS_Free();
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if(!r)
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printf("Bass_free error: %d\n", BASS_ErrorGetCode());
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stream = 0;
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}
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}
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/*
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// capture callback
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// length: bytes. short=2byte, 2channels, so it requests samples*4
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BOOL CALLBACK RecordingCallback(HRECORD handle, const void *buffer, DWORD length, void *user)
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{
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//printf("captured %ld samples\n",length/sizeof(float));
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float *fbuffer = (float *)buffer;
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//printf("w:%ld ",length/sizeof(float));
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for(int i=0; i<(length/sizeof(float)); i+=CHANNELS)
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{
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//printf("%f\n",fbuffer[i]);
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cap_write_fifo(fbuffer[i]);
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}
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return TRUE; // continue recording
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}
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*/
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// play callback
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// length: bytes. float=4byte, 2channels, so it requests samples*8
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DWORD CALLBACK WriteStream(HSTREAM handle, float *buffer, DWORD length, void *user)
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{
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int ret = pb_read_fifo(buffer,length/sizeof(float));
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if(ret == 0)
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{
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// fifo empty, send 00
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memset(buffer,0,length);
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}
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return length;
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}
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// ================ thread safe fifo for audio callback routines ===============
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pthread_mutex_t cap_crit_sec;
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pthread_mutex_t pb_crit_sec;
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#define CAP_LOCK pthread_mutex_lock(&cap_crit_sec)
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#define CAP_UNLOCK pthread_mutex_unlock(&cap_crit_sec)
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#define PB_LOCK pthread_mutex_lock(&pb_crit_sec)
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#define PB_UNLOCK pthread_mutex_unlock(&pb_crit_sec)
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#define AUDIO_BUFFERMAXTIME 2 // fifo can buffer this time in [s]
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#define AUDIO_PLAYBACK_BUFLEN (48000 * 10) // space for 10 seconds of samples
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/*#define AUDIO_CAPTURE_BUFLEN (48000*CHANNELS*AUDIO_BUFFERMAXTIME*UPSAMPLING)
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int cap_wridx=0;
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int cap_rdidx=0;
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float cap_buffer[AUDIO_CAPTURE_BUFLEN];
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*/
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int pb_wridx=0;
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int pb_rdidx=0;
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float pb_buffer[AUDIO_PLAYBACK_BUFLEN];
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/*
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// write one sample into the fifo
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// overwrite old data if the fifo is full
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void cap_write_fifo(float sample)
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{
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CAP_LOCK;
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cap_buffer[cap_wridx] = sample;
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if(++cap_wridx >= AUDIO_CAPTURE_BUFLEN) cap_wridx = 0;
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CAP_UNLOCK;
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}
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int cap_read_fifo(float *data)
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{
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CAP_LOCK;
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if (cap_rdidx == cap_wridx)
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{
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// Fifo empty, no data available
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CAP_UNLOCK;
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return 0;
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}
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*data = cap_buffer[cap_rdidx];
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if(++cap_rdidx >= AUDIO_CAPTURE_BUFLEN) cap_rdidx = 0;
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CAP_UNLOCK;
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return 1;
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}
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*/
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void pb_write_fifo(float sample)
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{
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PB_LOCK;
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// check if there is free space in fifo
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if(pb_fifo_freespace(1) == 0)
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{
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PB_UNLOCK;
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printf("************* pb fifo full\n");
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return;
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}
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pb_buffer[pb_wridx] = sample;
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if(++pb_wridx >= AUDIO_PLAYBACK_BUFLEN) pb_wridx = 0;
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PB_UNLOCK;
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//printf("write: pbw:%d pbr:%d\n",pb_wridx,pb_rdidx);
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}
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int pb_fifo_freespace(int nolock)
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{
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int freebuf = 0;
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if(nolock == 0) PB_LOCK;
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/*freebuf = AUDIO_PLAYBACK_BUFLEN - ((pb_wridx+AUDIO_PLAYBACK_BUFLEN+1 - pb_rdidx)%AUDIO_PLAYBACK_BUFLEN);
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freebuf %= AUDIO_PLAYBACK_BUFLEN;*/
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int elemInFifo = (pb_wridx + AUDIO_PLAYBACK_BUFLEN - pb_rdidx) % AUDIO_PLAYBACK_BUFLEN;
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freebuf = AUDIO_PLAYBACK_BUFLEN - elemInFifo;
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if(nolock == 0) PB_UNLOCK;
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//printf("fifolen:%d check: pbw:%d pbr:%d freebuf:%d\n",AUDIO_PLAYBACK_BUFLEN,pb_wridx,pb_rdidx,freebuf);
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return freebuf;
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}
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// read elements floats from fifo or return 0 if not enough floats are available
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int pb_read_fifo(float *data, int elements)
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{
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//printf("pb read fifo: %d\n",elements);
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PB_LOCK;
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int e = AUDIO_PLAYBACK_BUFLEN - pb_fifo_freespace(1);
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//if (pb_rdidx == pb_wridx)
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if(e < elements)
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{
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// Fifo empty, no data available
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PB_UNLOCK;
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//printf("pb fifo empty, need:%d have:%d size:%d\n",elements,e,AUDIO_PLAYBACK_BUFLEN);
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return 0;
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}
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for(int i=0; i<elements; i++)
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{
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data[i] = pb_buffer[pb_rdidx];
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if(++pb_rdidx >= AUDIO_PLAYBACK_BUFLEN) pb_rdidx = 0;
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}
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//printf("read %d floats\n",elements);
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PB_UNLOCK;
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return 1;
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}
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