me/portaudio
Watch
1
0
Fork
You've already forked portaudio
 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

alsa:

Browse source 
- improved host buffer size calculation: taking into account obligatory double buffering utilising formula (userFrames + MAX( userFrames, SR * suggestedLatency)), aligning host buffer with user buffer size, additional testing of host buffer size to avoid failure on snd_pcm_hw_params_set_period_size_near, additional logging for more convenient debugging
This commit is contained in:
dmitrykos 2010-07-30 10:44:18 +00:00
commit d9d12f6b82
1 changed files with 213 additions and 27 deletions
Download patch file Download diff file Expand all files Collapse all files

240
src/hostapi/alsa/pa_linux_alsa.c
View file

@ -1477,9 +1477,9 @@ static int CalculatePollTimeout( const PaAlsaStream *stream, unsigned long frame
/** Align value in backward direction.
*
* @param v: Value to align.
* @param align: Alignment value.
* @param align: Alignment.
*/
static unsigned long ALIGN_BWD(unsigned long v, unsigned long align)
static unsigned long PaAlsa_AlignBackward(unsigned long v, unsigned long align)
{
return ((v - (align ? v % align : 0)));
}
@ -1487,14 +1487,25 @@ static unsigned long ALIGN_BWD(unsigned long v, unsigned long align)
/** Align value in forward direction.
*
* @param v: Value to align.
* @param align: Alignment value.
* @param align: Alignment.
*/
static unsigned long ALIGN_FWD(unsigned long v, unsigned long align)
static unsigned long PaAlsa_AlignForward(unsigned long v, unsigned long align)
{
unsigned long remainder = (align ? (v % align) : 0);
if (remainder == 0)
return v;
return v + (align - remainder);
return (remainder != 0 ? v + (align - remainder) : v);
}
/** Get size of host buffer maintained from the number of user frames, sample rate and suggested latency. Minimum double buffering
* is maintained to allow 100% CPU usage inside user callback.
*
* @param userFramesPerBuffer: User buffer size in number of frames.
* @param suggestedLatency: User provided desired latency.
* @param sampleRate: Sample rate.
*/
static unsigned long PaAlsa_GetFramesPerHostBuffer(unsigned long userFramesPerBuffer, PaTime suggestedLatency, double sampleRate)
{
unsigned long frames = userFramesPerBuffer + PA_MAX( userFramesPerBuffer, (unsigned long)(suggestedLatency * sampleRate) );
return frames;
}
/** Determine size per host buffer.
@ -1507,51 +1518,208 @@ static PaError PaAlsaStreamComponent_DetermineFramesPerBuffer( PaAlsaStreamCompo
unsigned long framesPerUserBuffer, double sampleRate, snd_pcm_hw_params_t* hwParams, int* accurate )
{
PaError result = paNoError;
unsigned long bufferSize = framesPerUserBuffer + params->suggestedLatency * sampleRate, framesPerHostBuffer;
unsigned long bufferSize, framesPerHostBuffer;
int dir = 0;
PA_DEBUG(( "%s: frames per user-buffer = %lu\n", __FUNCTION__, framesPerUserBuffer ));
PA_DEBUG(( "%s: suggested latency = %f\n", __FUNCTION__, params->suggestedLatency ));
PA_DEBUG(( "%s: suggested host buffer size = %lu\n", __FUNCTION__, bufferSize ));
/* Calculate host buffer size */
bufferSize = PaAlsa_GetFramesPerHostBuffer(framesPerUserBuffer, params->suggestedLatency, sampleRate);
/* Log */
PA_DEBUG(( "%s: user-buffer (frames) = %lu\n", __FUNCTION__, framesPerUserBuffer ));
PA_DEBUG(( "%s: user-buffer (sec) = %f\n", __FUNCTION__, (double)(framesPerUserBuffer / sampleRate) ));
PA_DEBUG(( "%s: suggested latency (sec) = %f\n", __FUNCTION__, params->suggestedLatency ));
PA_DEBUG(( "%s: suggested host buffer (frames) = %lu\n", __FUNCTION__, bufferSize ));
PA_DEBUG(( "%s: suggested host buffer (sec) = %f\n", __FUNCTION__, (double)(bufferSize / sampleRate) ));
#ifdef PA_ALSA_USE_OBSOLETE_HOST_BUFFER_CALC
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 );
}
}
#endif
{
unsigned numPeriods = numPeriods_, maxPeriods = 0;
unsigned numPeriods = numPeriods_, maxPeriods = 0, minPeriods = numPeriods_;
/* It may be that the device only supports 2 periods for instance */
dir = 0;
ENSURE_( snd_pcm_hw_params_get_periods_min( hwParams, &minPeriods, &dir ), paUnanticipatedHostError )
ENSURE_( snd_pcm_hw_params_get_periods_max( hwParams, &maxPeriods, &dir ), paUnanticipatedHostError );
assert( maxPeriods > 1 );
numPeriods = PA_MIN( maxPeriods, numPeriods );
/* Align to 16 bytes for faster copying */
framesPerHostBuffer = ALIGN_FWD((bufferSize / numPeriods), 16);
/* Clamp to min/max */
numPeriods = PA_MIN(maxPeriods, PA_MAX(minPeriods, numPeriods));
PA_DEBUG(( "%s: periods min = %lu, max = %lu, req = %lu \n", __FUNCTION__, minPeriods, maxPeriods, numPeriods ));
#ifndef PA_ALSA_USE_OBSOLETE_HOST_BUFFER_CALC
/* Calculate period size */
framesPerHostBuffer = (bufferSize / numPeriods);
/* Align & test size */
if( framesPerUserBuffer != paFramesPerBufferUnspecified )
{
/* Align to user buffer size */
framesPerHostBuffer = PaAlsa_AlignForward(framesPerHostBuffer, framesPerUserBuffer);
/* Test (borrowed from older implementation) */
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;
}
}
}
#endif
#ifdef PA_ALSA_USE_OBSOLETE_HOST_BUFFER_CALC
if( framesPerUserBuffer != paFramesPerBufferUnspecified )
{
/* Try to get a power-of-two of the user buffer size. */
framesPerHostBuffer = framesPerUserBuffer;
if( framesPerHostBuffer < bufferSize )
{
while( bufferSize / framesPerHostBuffer > numPeriods )
{
framesPerHostBuffer *= 2;
}
/* One extra period is preferrable to one less (should be more robust) */
if( 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;
}
/* non-mmap mode needs a reasonably-sized buffer or it'll stutter */
if( !self->canMmap && framesPerHostBuffer < 2048 )
framesPerHostBuffer = 2048;
#endif
PA_DEBUG(( "%s: suggested host buffer period = %lu \n", __FUNCTION__, framesPerHostBuffer ));
}
{
/* Get min/max period sizes and adjust our chosen */
snd_pcm_uframes_t min = 0, max = 0;
ENSURE_( snd_pcm_hw_params_get_period_size_min( hwParams, &min, NULL ), paUnanticipatedHostError );
ENSURE_( snd_pcm_hw_params_get_period_size_max( hwParams, &max, NULL ), paUnanticipatedHostError );
if( framesPerHostBuffer < min )
{
PA_DEBUG(( "%s: The determined period size (%lu) is less than minimum (%lu)\n", __FUNCTION__,
framesPerHostBuffer, min ));
PA_DEBUG(( "%s: The determined period size (%lu) is less than minimum (%lu)\n", __FUNCTION__, framesPerHostBuffer, min ));
framesPerHostBuffer = min;
}
else if( framesPerHostBuffer > max )
else
if( framesPerHostBuffer > max )
{
PA_DEBUG(( "%s: The determined period size (%lu) is greater than maximum (%lu)\n", __FUNCTION__,
framesPerHostBuffer, max ));
PA_DEBUG(( "%s: The determined period size (%lu) is greater than maximum (%lu)\n", __FUNCTION__, framesPerHostBuffer, max ));
framesPerHostBuffer = max;
}
PA_DEBUG(( "%s: device period minimum = %lu\n", __FUNCTION__, min ));
PA_DEBUG(( "%s: device period maximum = %lu\n", __FUNCTION__, max ));
PA_DEBUG(( "%s: host buffer period = %lu\n", __FUNCTION__, framesPerHostBuffer ));
PA_DEBUG(( "%s: device period minimum = %lu\n", __FUNCTION__, min ));
PA_DEBUG(( "%s: device period maximum = %lu\n", __FUNCTION__, max ));
PA_DEBUG(( "%s: host buffer period = %lu\n", __FUNCTION__, framesPerHostBuffer ));
PA_DEBUG(( "%s: host buffer period latency = %f\n", __FUNCTION__, (double)(framesPerHostBuffer / sampleRate) ));
assert( framesPerHostBuffer >= min && framesPerHostBuffer <= max );
/* Try set period size */
dir = 0;
ENSURE_( snd_pcm_hw_params_set_period_size_near( self->pcm, hwParams, &framesPerHostBuffer, &dir ),
paUnanticipatedHostError );
ENSURE_( snd_pcm_hw_params_set_period_size_near( self->pcm, hwParams, &framesPerHostBuffer, &dir ), paUnanticipatedHostError );
if( dir != 0 )
{
PA_DEBUG(( "%s: The configured period size is non-integer.\n", __FUNCTION__, dir ));
@ -1944,6 +2112,8 @@ static PaError OpenStream( struct PaUtilHostApiRepresentation *hostApi,
stream->streamRepresentation.streamInfo.outputLatency = outputLatency + (PaTime)(
PaUtil_GetBufferProcessorOutputLatency( &stream->bufferProcessor ) / sampleRate);
PA_DEBUG(( "%s: Stream: framesPerBuffer = %lu, maxFramesPerHostBuffer = %lu, latency = i(%f)/o(%f), \n", __FUNCTION__, framesPerBuffer, stream->maxFramesPerHostBuffer, stream->streamRepresentation.streamInfo.inputLatency, stream->streamRepresentation.streamInfo.outputLatency));
*s = (PaStream*)stream;
return result;
@ -2273,6 +2443,7 @@ static double GetStreamCpuLoad( PaStream* s )
static int SetApproximateSampleRate( snd_pcm_t *pcm, snd_pcm_hw_params_t *hwParams, double sampleRate )
{
PaError result = paNoError;
unsigned long approx = (unsigned long) sampleRate;
int dir = 0;
double fraction = sampleRate - approx;
@ -2290,7 +2461,22 @@ static int SetApproximateSampleRate( snd_pcm_t *pcm, snd_pcm_hw_params_t *hwPara
dir = 1;
}
return snd_pcm_hw_params_set_rate( pcm, hwParams, approx, dir );
ENSURE_( snd_pcm_hw_params_set_rate( pcm, hwParams, approx, dir ), paUnanticipatedHostError );
end:
return result;
error:
/* Log */
{
unsigned int _min = 0, _max = 0; int _dir = 0;
ENSURE_( snd_pcm_hw_params_get_rate_min( hwParams, &_min, &_dir ), paUnanticipatedHostError );
ENSURE_( snd_pcm_hw_params_get_rate_max( hwParams, &_max, &_dir ), paUnanticipatedHostError );
PA_DEBUG(( "%s: SR min = %d, max = %d, req = %lu\n", __FUNCTION__, _min, _max, approx ));
}
goto end;
}
/* Return exact sample rate in param sampleRate */