/** 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)));
}
/** 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.
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 ));
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;
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;
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 */
projects / portaudio / commitdiff