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SDRdaemon plugin: auto skew correction #1

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This commit is contained in:
f4exb 2016-02-22 12:10:13 +01:00
parent 2d018f7968
commit 898178bd12
3 changed files with 52 additions and 15 deletions
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46
plugins/samplesource/sdrdaemon/sdrdaemonbuffer.cpp
View File

@ -39,7 +39,8 @@ SDRdaemonBuffer::SDRdaemonBuffer(uint32_t rateDivider) :
m_nbLz4SuccessfulDecodes(0),
m_nbLz4CRCOK(0),
m_dataCRC(0),
m_sampleRate(1000000),
m_sampleRateStream(0),
m_sampleRate(0),
m_sampleBytes(2),
m_sampleBits(12),
m_writeIndex(0),
@ -48,7 +49,11 @@ SDRdaemonBuffer::SDRdaemonBuffer(uint32_t rateDivider) :
m_rawBuffer(0),
m_chunkSize(0),
m_bytesInBlock(0),
m_nbBlocks(0)
m_nbBlocks(0),
m_readCycles(0),
m_lastWriteIndex(0),
m_skewRateSum(0.0),
m_skewRate(0.0)
{
m_currentMeta.init();
}
@ -106,6 +111,13 @@ bool SDRdaemonBuffer::readMeta(char *array, uint32_t length)
uint32_t frameSize = m_iqSampleSize * metaData->m_nbSamples * metaData->m_nbBlocks;
uint32_t sampleRate = metaData->m_sampleRate;
if (sampleRate != m_sampleRateStream)
{
m_sampleRateStream = sampleRate;
}
sampleRate += (((int) (sampleRate * m_skewRate)) / m_rateDivider) * m_rateDivider;
if (metaData->m_sampleBytes & 0x10)
{
m_lz4 = true;
@ -240,18 +252,32 @@ void SDRdaemonBuffer::writeToRawBufferLZ4(const char *array, uint32_t length)
uint8_t *SDRdaemonBuffer::readDataChunk()
{
// relies on the fact that we always have an integer number of chunks in the raw buffer
if (m_readChunkIndex == m_rateDivider * 2) // go back to start of raw buffer
{
double oneCycleSkew = 0;
if (m_readChunkIndex == m_rateDivider * 2) // go back to start or middle of raw buffer
if (m_readCycles > 0)
{
// make sure the read and write pointers are not in the same half of the raw buffer
if (m_writeIndex < m_rateDivider * m_chunkSize - 1)
{
m_readChunkIndex = m_rateDivider; // go to middle
oneCycleSkew = (double) ((int) m_writeIndex - (int) m_lastWriteIndex) / (double) m_rawSize;
m_skewRateSum += oneCycleSkew;
}
else
//qDebug("SDRdaemonBuffer::readDataChunk: %d / %d (%lf)", m_writeIndex, m_rawSize, oneCycleSkew);
if (m_readCycles && ((m_writeIndex < m_rawSize / 10) || (m_rawSize - m_writeIndex < m_rawSize / 10)))
{
m_skewRate = m_skewRateSum / m_readCycles;
if (m_skewRate > 0.04) {
m_skewRate = 0.04;
} else if (m_skewRate < -0.04) {
m_skewRate = -0.04;
}
qDebug("SDRdaemonBuffer::readDataChunk: m_skewRate: %lf", m_skewRate);
}
m_readChunkIndex = 0; // go to start
}
m_lastWriteIndex = m_writeIndex;
m_readCycles++;
}
uint32_t readIndex = m_readChunkIndex;
@ -292,6 +318,8 @@ void SDRdaemonBuffer::updateBufferSize(uint32_t sampleRate)
m_writeIndex = 0;
m_readChunkIndex = m_rateDivider;
m_readCycles = 0;
m_skewRateSum = 0;
std::cerr << "SDRdaemonBuffer::updateBufferSize:"
<< " sampleRate: " << sampleRate

9
plugins/samplesource/sdrdaemon/sdrdaemonbuffer.h
View File

@ -67,6 +67,7 @@ public:
void writeData(char *array, uint32_t length); //!< Write data into buffer.
uint8_t *readDataChunk(); //!< Read a chunk of data from buffer
const MetaData& getCurrentMeta() const { return m_currentMeta; }
uint32_t getSampleRate() const { return m_sampleRate; }
void updateBlockCounts(uint32_t nbBytesReceived);
bool isSync() const { return m_sync; }
bool isSyncLocked() const { return m_syncLock; }
@ -101,7 +102,8 @@ private:
uint32_t m_nbLz4CRCOK;
uint64_t m_dataCRC;
uint32_t m_sampleRate; //!< Current sample rate in Hz
uint32_t m_sampleRateStream; //!< Current sample rate from the stream
uint32_t m_sampleRate; //!< Current actual sample rate in Hz
uint8_t m_sampleBytes; //!< Current number of bytes per I or Q sample
uint8_t m_sampleBits; //!< Current number of effective bits per sample
@ -112,6 +114,11 @@ private:
uint32_t m_chunkSize; //!< Size of a chunk of samples in bytes
uint32_t m_bytesInBlock; //!< Number of bytes received in the current UDP block
uint32_t m_nbBlocks; //!< Number of UDP blocks received in the current frame
uint32_t m_readCycles; //!< Count of read cycles over raw buiffer
uint32_t m_lastWriteIndex; //!< Write index at last skew estimation
double m_skewRateSum;
double m_skewRate;
};

8
plugins/samplesource/sdrdaemon/sdrdaemonudphandler.cpp
View File

@ -137,10 +137,12 @@ void SDRdaemonUDPHandler::processData()
m_tv_sec = metaData.m_tv_sec;
m_tv_usec = metaData.m_tv_usec;
if (m_samplerate != metaData.m_sampleRate)
uint32_t sampleRate = m_sdrDaemonBuffer.getSampleRate();
if (m_samplerate != sampleRate)
{
setSamplerate(metaData.m_sampleRate);
m_samplerate = metaData.m_sampleRate;
setSamplerate(sampleRate);
m_samplerate = sampleRate;
change = true;
}