#define PA_MME_USE_HIGH_DEFAULT_LATENCY_ (0) /* For debugging glitches. */
#if PA_MME_USE_HIGH_DEFAULT_LATENCY_
- #define PA_MME_WIN_9X_DEFAULT_LATENCY_ (0.4)
- #define PA_MME_MIN_HOST_OUTPUT_BUFFER_COUNT_ (4)
- #define PA_MME_MIN_HOST_INPUT_BUFFER_COUNT_FULL_DUPLEX_ (4)
- #define PA_MME_MIN_HOST_INPUT_BUFFER_COUNT_HALF_DUPLEX_ (4)
- #define PA_MME_MIN_HOST_BUFFER_FRAMES_WHEN_UNSPECIFIED_ (16)
- #define PA_MME_MAX_HOST_BUFFER_SECS_ (0.3) /* Do not exceed unless user buffer exceeds */
- #define PA_MME_MAX_HOST_BUFFER_BYTES_ (32 * 1024) /* Has precedence over PA_MME_MAX_HOST_BUFFER_SECS_, some drivers are known to crash with buffer sizes > 32k */
+ #define PA_MME_WIN_9X_DEFAULT_LATENCY_ (0.4)
+ #define PA_MME_MIN_HOST_OUTPUT_BUFFER_COUNT_ (4)
+ #define PA_MME_MIN_HOST_INPUT_BUFFER_COUNT_FULL_DUPLEX_ (4)
+ #define PA_MME_MIN_HOST_INPUT_BUFFER_COUNT_HALF_DUPLEX_ (4)
+ #define PA_MME_HOST_BUFFER_GRANULARITY_FRAMES_WHEN_UNSPECIFIED_ (16)
+ #define PA_MME_MAX_HOST_BUFFER_SECS_ (0.3) /* Do not exceed unless user buffer exceeds */
+ #define PA_MME_MAX_HOST_BUFFER_BYTES_ (32 * 1024) /* Has precedence over PA_MME_MAX_HOST_BUFFER_SECS_, some drivers are known to crash with buffer sizes > 32k */
#else
- #define PA_MME_WIN_9X_DEFAULT_LATENCY_ (0.2)
- #define PA_MME_MIN_HOST_OUTPUT_BUFFER_COUNT_ (2)
- #define PA_MME_MIN_HOST_INPUT_BUFFER_COUNT_FULL_DUPLEX_ (3)
- #define PA_MME_MIN_HOST_INPUT_BUFFER_COUNT_HALF_DUPLEX_ (2)
- #define PA_MME_MIN_HOST_BUFFER_FRAMES_WHEN_UNSPECIFIED_ (16)
- #define PA_MME_MAX_HOST_BUFFER_SECS_ (0.1) /* Do not exceed unless user buffer exceeds */
- #define PA_MME_MAX_HOST_BUFFER_BYTES_ (32 * 1024) /* Has precedence over PA_MME_MAX_HOST_BUFFER_SECS_, some drivers are known to crash with buffer sizes > 32k */
+ #define PA_MME_WIN_9X_DEFAULT_LATENCY_ (0.2)
+ #define PA_MME_MIN_HOST_OUTPUT_BUFFER_COUNT_ (2)
+ #define PA_MME_MIN_HOST_INPUT_BUFFER_COUNT_FULL_DUPLEX_ (3) /* always use at least 3 input buffers for full duplex */
+ #define PA_MME_MIN_HOST_INPUT_BUFFER_COUNT_HALF_DUPLEX_ (2)
+ #define PA_MME_HOST_BUFFER_GRANULARITY_FRAMES_WHEN_UNSPECIFIED_ (16)
+ #define PA_MME_MAX_HOST_BUFFER_SECS_ (0.1) /* Do not exceed unless user buffer exceeds */
+ #define PA_MME_MAX_HOST_BUFFER_BYTES_ (32 * 1024) /* Has precedence over PA_MME_MAX_HOST_BUFFER_SECS_, some drivers are known to crash with buffer sizes > 32k */
#endif
/* Use higher latency for NT because it is even worse at real-time
#define PA_MME_WIN_NT_DEFAULT_LATENCY_ (PA_MME_WIN_9X_DEFAULT_LATENCY_ * 2)
#define PA_MME_WIN_WDM_DEFAULT_LATENCY_ (PA_MME_WIN_9X_DEFAULT_LATENCY_)
+/* When client suggestedLatency could result in many host buffers, we aim to have around 8,
+ based off Windows documentation that suggests that the kmixer uses 8 buffers. This choice
+ is somewhat arbitrary here, since we havn't observed significant stability degredation
+ with using either more, or less buffers.
+*/
+
+#define PA_MME_TARGET_HOST_BUFFER_COUNT_ 8
#define PA_MME_MIN_TIMEOUT_MSEC_ (1000)
MMRESULT mmresult;
WAVEOUTCAPS woc;
PaDeviceInfo *deviceInfo = &winMmeDeviceInfo->inheritedDeviceInfo;
+#ifdef PAWIN_USE_WDMKS_DEVICE_INFO
int wdmksDeviceOutputChannelCountIsKnown;
+#endif
*success = 0;
}
-
-static void SelectBufferSizeAndCount( unsigned long baseBufferSize,
- unsigned long requestedLatency,
- unsigned long baseBufferCount, unsigned long minimumBufferCount,
- unsigned long maximumBufferSize, unsigned long *hostBufferSize,
- unsigned long *hostBufferCount )
+static unsigned long ComputeHostBufferCountForFixedBufferSizeFrames(
+ unsigned long suggestedLatencyFrames,
+ unsigned long hostBufferSizeFrames,
+ unsigned long minimumBufferCount )
{
- unsigned long sizeMultiplier, bufferCount, latency;
- unsigned long nextLatency, nextBufferSize;
- int baseBufferSizeIsPowerOfTwo;
-
- sizeMultiplier = 1;
- bufferCount = baseBufferCount;
+ /* Calculate the number of buffers of length hostFramesPerBuffer
+ that fit in suggestedLatencyFrames, rounding up to the next integer.
- /* count-1 below because latency is always determined by one less
- than the total number of buffers.
+ The exact formula for round-up is:
+ ((suggestedLatencyFrames + (hostFramesPerBuffer - 1)) / hostFramesPerBuffer)
+ However we subtract 2 instead of 1 below to account for rounding errors.
+ This ensures we don't erroneously overallocate an extra buffer due to a one-sample rounding error.
*/
- latency = (baseBufferSize * sizeMultiplier) * (bufferCount-1);
- if( latency > requestedLatency )
- {
+ unsigned long resultBufferCount = ((suggestedLatencyFrames + (hostBufferSizeFrames - 2)) / hostBufferSizeFrames);
- /* reduce number of buffers without falling below suggested latency */
-
- nextLatency = (baseBufferSize * sizeMultiplier) * (bufferCount-2);
- while( bufferCount > minimumBufferCount && nextLatency >= requestedLatency )
- {
- --bufferCount;
- nextLatency = (baseBufferSize * sizeMultiplier) * (bufferCount-2);
- }
+ /* We always need one extra buffer for processing while the rest are queued/playing.
+ i.e. latency is framesPerBuffer * (bufferCount - 1)
+ */
+ resultBufferCount += 1;
- }else if( latency < requestedLatency ){
+ if( resultBufferCount < minimumBufferCount ) /* clamp to minimum buffer count */
+ resultBufferCount = minimumBufferCount;
- baseBufferSizeIsPowerOfTwo = (! (baseBufferSize & (baseBufferSize - 1)));
- if( baseBufferSizeIsPowerOfTwo ){
+ return resultBufferCount;
+}
- /* double size of buffers without exceeding requestedLatency */
- nextBufferSize = (baseBufferSize * (sizeMultiplier*2));
- nextLatency = nextBufferSize * (bufferCount-1);
- while( nextBufferSize <= maximumBufferSize
- && nextLatency < requestedLatency )
- {
- sizeMultiplier *= 2;
- nextBufferSize = (baseBufferSize * (sizeMultiplier*2));
- nextLatency = nextBufferSize * (bufferCount-1);
- }
+static PaError SelectHostBufferSizeFramesAndHostBufferCount(
+ unsigned long suggestedLatencyFrames,
+ unsigned long userFramesPerBuffer,
+ unsigned long minimumBufferCount,
+ unsigned long preferredMaximumBufferSizeFrames, /* try not to exceed this. for example, don't exceed when coalescing buffers */
+ unsigned long absoluteMaximumBufferSizeFrames, /* never exceed this, a hard limit */
+ unsigned long *hostBufferSizeFrames,
+ unsigned long *hostBufferCount )
+{
+ if( userFramesPerBuffer == paFramesPerBufferUnspecified ){
- }else{
+ *hostBufferSizeFrames = PA_MME_HOST_BUFFER_GRANULARITY_FRAMES_WHEN_UNSPECIFIED_;
- /* increase size of buffers upto first excess of requestedLatency */
+ }else{
- nextBufferSize = (baseBufferSize * (sizeMultiplier+1));
- nextLatency = nextBufferSize * (bufferCount-1);
- while( nextBufferSize <= maximumBufferSize
- && nextLatency < requestedLatency )
- {
- ++sizeMultiplier;
- nextBufferSize = (baseBufferSize * (sizeMultiplier+1));
- nextLatency = nextBufferSize * (bufferCount-1);
- }
+ *hostBufferSizeFrames = userFramesPerBuffer;
- if( nextLatency < requestedLatency )
- ++sizeMultiplier;
+ if( *hostBufferSizeFrames > absoluteMaximumBufferSizeFrames ){
+ /* user has requested a user buffer that's larger than what we can handle */
+
+ /* @todo FIXME right now we allow the user to request an oversize host buffer,
+ even though elsewhere in the code there are suggestions that oversize buffers
+ can cause crashes with some drivers. */
+ /* return paBufferTooBig; */
}
+ }
+
+ /* compute a host buffer count based on suggestedLatencyFrames and our granularity */
- /* increase number of buffers until requestedLatency is reached */
+ *hostBufferCount = ComputeHostBufferCountForFixedBufferSizeFrames(
+ suggestedLatencyFrames, *hostBufferSizeFrames, minimumBufferCount );
- latency = (baseBufferSize * sizeMultiplier) * (bufferCount-1);
- while( latency < requestedLatency )
- {
- ++bufferCount;
- latency = (baseBufferSize * sizeMultiplier) * (bufferCount-1);
+ /* consider coalescing multiple user buffers into each host buffer */
+
+ if( *hostBufferCount >= PA_MME_TARGET_HOST_BUFFER_COUNT_ * 2 ){
+
+ /* If there are too many host buffers we would like to coalesce
+ them by packing an integer number of user buffers into each host buffer.
+ We try to coalesce such that hostBufferCount will lie between
+ PA_MME_TARGET_HOST_BUFFER_COUNT_ and (PA_MME_TARGET_HOST_BUFFER_COUNT_*2)-1.
+ We limit coalescing to avoid exceeding either absoluteMaximumBufferSizeFrames and
+ preferredMaximumBufferSizeFrames.
+ */
+
+ unsigned long maxCoalescedBufferSizeFrames = (absoluteMaximumBufferSizeFrames < preferredMaximumBufferSizeFrames) /* min of our limits */
+ ? absoluteMaximumBufferSizeFrames
+ : preferredMaximumBufferSizeFrames;
+
+ unsigned long maxUserBuffersPerHostBuffer = maxCoalescedBufferSizeFrames / *hostBufferSizeFrames; /* don't coalesce more than this */
+
+ /* we truncate here to compute a conservative value of numUserBuffersPerHostBuffer
+ then we recompute hostBufferCount after coalescing.
+ */
+ unsigned long numUserBuffersPerHostBuffer = *hostBufferCount / PA_MME_TARGET_HOST_BUFFER_COUNT_;
+ if( numUserBuffersPerHostBuffer > maxUserBuffersPerHostBuffer )
+ numUserBuffersPerHostBuffer = maxUserBuffersPerHostBuffer;
+
+ if( numUserBuffersPerHostBuffer > 1 ){
+ *hostBufferSizeFrames *= numUserBuffersPerHostBuffer;
+
+ /* recompute hostBufferCount to approximate suggestedLatencyFrames now that hostBufferSizeFrames is larger */
+ *hostBufferCount = ComputeHostBufferCountForFixedBufferSizeFrames(
+ suggestedLatencyFrames, *hostBufferSizeFrames, minimumBufferCount );
}
}
- *hostBufferSize = baseBufferSize * sizeMultiplier;
- *hostBufferCount = bufferCount;
+ return paNoError;
}
-static void ReselectBufferCount( unsigned long bufferSize,
- unsigned long requestedLatency,
- unsigned long baseBufferCount, unsigned long minimumBufferCount,
- unsigned long *hostBufferCount )
+static PaError CalculateMaxHostSampleFrameSizeBytes(
+ int channelCount,
+ PaSampleFormat hostSampleFormat,
+ const PaWinMmeStreamInfo *streamInfo,
+ int *hostSampleFrameSizeBytes )
{
- unsigned long bufferCount, latency;
- unsigned long nextLatency;
-
- bufferCount = baseBufferCount;
-
- /* count-1 below because latency is always determined by one less
- than the total number of buffers.
+ unsigned int i;
+ /* PA WMME streams may aggregate multiple WMME devices. When the stream addresses
+ more than one device in a single direction, maxDeviceChannelCount is the maximum
+ number of channels used by a single device.
*/
- latency = bufferSize * (bufferCount-1);
-
- if( latency > requestedLatency )
+ int maxDeviceChannelCount = channelCount;
+ int hostSampleSizeBytes = Pa_GetSampleSize( hostSampleFormat );
+ if( hostSampleSizeBytes < 0 )
{
- /* reduce number of buffers without falling below suggested latency */
+ return hostSampleSizeBytes; /* the value of hostSampleSize here is an error code, not a sample size */
+ }
- nextLatency = bufferSize * (bufferCount-2);
- while( bufferCount > minimumBufferCount && nextLatency >= requestedLatency )
+ if( streamInfo && ( streamInfo->flags & paWinMmeUseMultipleDevices ) )
+ {
+ maxDeviceChannelCount = streamInfo->devices[0].channelCount;
+ for( i=1; i< streamInfo->deviceCount; ++i )
{
- --bufferCount;
- nextLatency = bufferSize * (bufferCount-2);
+ if( streamInfo->devices[i].channelCount > maxDeviceChannelCount )
+ maxDeviceChannelCount = streamInfo->devices[i].channelCount;
}
-
- }else if( latency < requestedLatency ){
-
- /* increase number of buffers until requestedLatency is reached */
-
- latency = bufferSize * (bufferCount-1);
- while( latency < requestedLatency )
- {
- ++bufferCount;
- latency = bufferSize * (bufferCount-1);
- }
}
- *hostBufferCount = bufferCount;
+ *hostSampleFrameSizeBytes = hostSampleSizeBytes * maxDeviceChannelCount;
+
+ return paNoError;
}
unsigned long *hostFramesPerInputBuffer, unsigned long *hostInputBufferCount,
unsigned long *hostFramesPerOutputBuffer, unsigned long *hostOutputBufferCount,
int inputChannelCount, PaSampleFormat hostInputSampleFormat,
- PaTime suggestedInputLatency, PaWinMmeStreamInfo *inputStreamInfo,
+ PaTime suggestedInputLatency, const PaWinMmeStreamInfo *inputStreamInfo,
int outputChannelCount, PaSampleFormat hostOutputSampleFormat,
- PaTime suggestedOutputLatency, PaWinMmeStreamInfo *outputStreamInfo,
+ PaTime suggestedOutputLatency, const PaWinMmeStreamInfo *outputStreamInfo,
double sampleRate, unsigned long userFramesPerBuffer )
{
PaError result = paNoError;
- int effectiveInputChannelCount, effectiveOutputChannelCount;
- int hostInputFrameSize = 0;
- unsigned int i;
- if( inputChannelCount > 0 )
+ if( inputChannelCount > 0 ) /* stream has input */
{
- int hostInputSampleSize = Pa_GetSampleSize( hostInputSampleFormat );
- if( hostInputSampleSize < 0 )
- {
- result = hostInputSampleSize; /* this is an error code */
+ int hostInputFrameSizeBytes;
+ result = CalculateMaxHostSampleFrameSizeBytes(
+ inputChannelCount, hostInputSampleFormat, inputStreamInfo, &hostInputFrameSizeBytes );
+ if( result != paNoError )
goto error;
- }
-
- if( inputStreamInfo
- && ( inputStreamInfo->flags & paWinMmeUseMultipleDevices ) )
- {
- /* set effectiveInputChannelCount to the largest number of
- channels on any one device.
- */
- effectiveInputChannelCount = 0;
- for( i=0; i< inputStreamInfo->deviceCount; ++i )
- {
- if( inputStreamInfo->devices[i].channelCount > effectiveInputChannelCount )
- effectiveInputChannelCount = inputStreamInfo->devices[i].channelCount;
- }
- }
- else
- {
- effectiveInputChannelCount = inputChannelCount;
- }
-
- hostInputFrameSize = hostInputSampleSize * effectiveInputChannelCount;
if( inputStreamInfo
&& ( inputStreamInfo->flags & paWinMmeUseLowLevelLatencyParameters ) )
{
+ /* input - using low level latency parameters if provided */
+
if( inputStreamInfo->bufferCount <= 0
|| inputStreamInfo->framesPerBuffer <= 0 )
{
}
else
{
- unsigned long hostBufferSizeBytes, hostBufferCount;
+ /* input - not using low level latency parameters, so compute
+ hostFramesPerInputBuffer and hostInputBufferCount
+ based on userFramesPerBuffer and suggestedInputLatency. */
+
unsigned long minimumBufferCount = (outputChannelCount > 0)
? PA_MME_MIN_HOST_INPUT_BUFFER_COUNT_FULL_DUPLEX_
: PA_MME_MIN_HOST_INPUT_BUFFER_COUNT_HALF_DUPLEX_;
- unsigned long maximumBufferSize = (long) ((PA_MME_MAX_HOST_BUFFER_SECS_ * sampleRate) * hostInputFrameSize);
- if( maximumBufferSize > PA_MME_MAX_HOST_BUFFER_BYTES_ )
- maximumBufferSize = PA_MME_MAX_HOST_BUFFER_BYTES_;
-
- /* compute the following in bytes, then convert back to frames */
-
- SelectBufferSizeAndCount(
- ((userFramesPerBuffer == paFramesPerBufferUnspecified)
- ? PA_MME_MIN_HOST_BUFFER_FRAMES_WHEN_UNSPECIFIED_
- : userFramesPerBuffer ) * hostInputFrameSize, /* baseBufferSize */
- ((unsigned long)(suggestedInputLatency * sampleRate)) * hostInputFrameSize, /* suggestedLatency */
- 4, /* baseBufferCount */
- minimumBufferCount, maximumBufferSize,
- &hostBufferSizeBytes, &hostBufferCount );
-
- *hostFramesPerInputBuffer = hostBufferSizeBytes / hostInputFrameSize;
- *hostInputBufferCount = hostBufferCount;
+ result = SelectHostBufferSizeFramesAndHostBufferCount(
+ (unsigned long)(suggestedInputLatency * sampleRate),
+ userFramesPerBuffer,
+ minimumBufferCount,
+ (unsigned long)(PA_MME_MAX_HOST_BUFFER_SECS_ * sampleRate), /* in frames. preferred maximum */
+ (PA_MME_MAX_HOST_BUFFER_BYTES_ / hostInputFrameSizeBytes), /* in frames. a hard limit. note truncation due to
+ division is intentional here to limit max bytes */
+ hostFramesPerInputBuffer,
+ hostInputBufferCount );
+ if( result != paNoError )
+ goto error;
}
}
else
*hostInputBufferCount = 0;
}
- if( outputChannelCount > 0 )
+ if( outputChannelCount > 0 ) /* stream has output */
{
if( outputStreamInfo
&& ( outputStreamInfo->flags & paWinMmeUseLowLevelLatencyParameters ) )
{
+ /* output - using low level latency parameters */
+
if( outputStreamInfo->bufferCount <= 0
|| outputStreamInfo->framesPerBuffer <= 0 )
{
*hostFramesPerOutputBuffer = outputStreamInfo->framesPerBuffer;
*hostOutputBufferCount = outputStreamInfo->bufferCount;
-
if( inputChannelCount > 0 ) /* full duplex */
{
+ /* harmonize hostFramesPerInputBuffer and hostFramesPerOutputBuffer */
+
if( *hostFramesPerInputBuffer != *hostFramesPerOutputBuffer )
{
if( inputStreamInfo
&& ( inputStreamInfo->flags & paWinMmeUseLowLevelLatencyParameters ) )
{
/* a custom StreamInfo was used for specifying both input
- and output buffer sizes, the larger buffer size
+ and output buffer sizes. We require that the larger buffer size
must be a multiple of the smaller buffer size */
if( *hostFramesPerInputBuffer < *hostFramesPerOutputBuffer )
else
{
/* a custom StreamInfo was not used for specifying the input buffer size,
- so use the output buffer size, and approximately the same latency. */
+ so use the output buffer size, and approximately the suggested input latency. */
*hostFramesPerInputBuffer = *hostFramesPerOutputBuffer;
- *hostInputBufferCount = (((unsigned long)(suggestedInputLatency * sampleRate)) / *hostFramesPerInputBuffer) + 1;
- if( *hostInputBufferCount < PA_MME_MIN_HOST_INPUT_BUFFER_COUNT_FULL_DUPLEX_ )
- *hostInputBufferCount = PA_MME_MIN_HOST_INPUT_BUFFER_COUNT_FULL_DUPLEX_;
+ *hostInputBufferCount = ComputeHostBufferCountForFixedBufferSizeFrames(
+ (unsigned long)(suggestedInputLatency * sampleRate),
+ *hostFramesPerInputBuffer,
+ PA_MME_MIN_HOST_INPUT_BUFFER_COUNT_FULL_DUPLEX_ );
}
}
}
}
else
{
- unsigned long hostBufferSizeBytes, hostBufferCount;
- unsigned long minimumBufferCount = PA_MME_MIN_HOST_OUTPUT_BUFFER_COUNT_;
- unsigned long maximumBufferSize;
- int hostOutputFrameSize;
- int hostOutputSampleSize;
-
- hostOutputSampleSize = Pa_GetSampleSize( hostOutputSampleFormat );
- if( hostOutputSampleSize < 0 )
- {
- result = hostOutputSampleSize;
- goto error;
- }
-
- if( outputStreamInfo
- && ( outputStreamInfo->flags & paWinMmeUseMultipleDevices ) )
- {
- /* set effectiveOutputChannelCount to the largest number of
- channels on any one device.
- */
- effectiveOutputChannelCount = 0;
- for( i=0; i< outputStreamInfo->deviceCount; ++i )
- {
- if( outputStreamInfo->devices[i].channelCount > effectiveOutputChannelCount )
- effectiveOutputChannelCount = outputStreamInfo->devices[i].channelCount;
- }
- }
- else
- {
- effectiveOutputChannelCount = outputChannelCount;
- }
-
- hostOutputFrameSize = hostOutputSampleSize * effectiveOutputChannelCount;
-
- maximumBufferSize = (long) ((PA_MME_MAX_HOST_BUFFER_SECS_ * sampleRate) * hostOutputFrameSize);
- if( maximumBufferSize > PA_MME_MAX_HOST_BUFFER_BYTES_ )
- maximumBufferSize = PA_MME_MAX_HOST_BUFFER_BYTES_;
+ /* output - no low level latency parameters, so compute hostFramesPerOutputBuffer and hostOutputBufferCount
+ based on userFramesPerBuffer and suggestedOutputLatency. */
+ int hostOutputFrameSizeBytes;
+ result = CalculateMaxHostSampleFrameSizeBytes(
+ outputChannelCount, hostOutputSampleFormat, outputStreamInfo, &hostOutputFrameSizeBytes );
+ if( result != paNoError )
+ goto error;
- /* compute the following in bytes, then convert back to frames */
-
- SelectBufferSizeAndCount(
- ((userFramesPerBuffer == paFramesPerBufferUnspecified)
- ? PA_MME_MIN_HOST_BUFFER_FRAMES_WHEN_UNSPECIFIED_
- : userFramesPerBuffer ) * hostOutputFrameSize, /* baseBufferSize */
- ((unsigned long)(suggestedOutputLatency * sampleRate)) * hostOutputFrameSize, /* suggestedLatency */
- 4, /* baseBufferCount */
- minimumBufferCount,
- maximumBufferSize,
- &hostBufferSizeBytes, &hostBufferCount );
-
- *hostFramesPerOutputBuffer = hostBufferSizeBytes / hostOutputFrameSize;
- *hostOutputBufferCount = hostBufferCount;
-
+ /* compute the output buffer size and count */
+
+ result = SelectHostBufferSizeFramesAndHostBufferCount(
+ (unsigned long)(suggestedOutputLatency * sampleRate),
+ userFramesPerBuffer,
+ PA_MME_MIN_HOST_OUTPUT_BUFFER_COUNT_,
+ (unsigned long)(PA_MME_MAX_HOST_BUFFER_SECS_ * sampleRate), /* in frames. preferred maximum */
+ (PA_MME_MAX_HOST_BUFFER_BYTES_ / hostOutputFrameSizeBytes), /* in frames. a hard limit. note truncation due to
+ division is intentional here to limit max bytes */
+ hostFramesPerOutputBuffer,
+ hostOutputBufferCount );
+ if( result != paNoError )
+ goto error;
- if( inputChannelCount > 0 )
+ if( inputChannelCount > 0 ) /* full duplex */
{
+ /* harmonize hostFramesPerInputBuffer and hostFramesPerOutputBuffer */
+
/* ensure that both input and output buffer sizes are the same.
if they don't match at this stage, choose the smallest one
- and use that for input and output
+ and use that for input and output and recompute the corresponding
+ buffer count accordingly.
*/
if( *hostFramesPerOutputBuffer != *hostFramesPerInputBuffer )
{
if( hostFramesPerInputBuffer < hostFramesPerOutputBuffer )
{
- unsigned long framesPerHostBuffer = *hostFramesPerInputBuffer;
-
- minimumBufferCount = PA_MME_MIN_HOST_OUTPUT_BUFFER_COUNT_;
- ReselectBufferCount(
- framesPerHostBuffer * hostOutputFrameSize, /* bufferSize */
- ((unsigned long)(suggestedOutputLatency * sampleRate)) * hostOutputFrameSize, /* suggestedLatency */
- 4, /* baseBufferCount */
- minimumBufferCount,
- &hostBufferCount );
-
- *hostFramesPerOutputBuffer = framesPerHostBuffer;
- *hostOutputBufferCount = hostBufferCount;
+ *hostFramesPerOutputBuffer = *hostFramesPerInputBuffer;
+
+ *hostOutputBufferCount = ComputeHostBufferCountForFixedBufferSizeFrames(
+ (unsigned long)(suggestedOutputLatency * sampleRate),
+ *hostOutputBufferCount,
+ PA_MME_MIN_HOST_OUTPUT_BUFFER_COUNT_ );
}
else
{
- unsigned long framesPerHostBuffer = *hostFramesPerOutputBuffer;
-
- minimumBufferCount = PA_MME_MIN_HOST_INPUT_BUFFER_COUNT_FULL_DUPLEX_;
- ReselectBufferCount(
- framesPerHostBuffer * hostInputFrameSize, /* bufferSize */
- ((unsigned long)(suggestedInputLatency * sampleRate)) * hostInputFrameSize, /* suggestedLatency */
- 4, /* baseBufferCount */
- minimumBufferCount,
- &hostBufferCount );
-
- *hostFramesPerInputBuffer = framesPerHostBuffer;
- *hostInputBufferCount = hostBufferCount;
+ *hostFramesPerInputBuffer = *hostFramesPerOutputBuffer;
+
+ *hostInputBufferCount = ComputeHostBufferCountForFixedBufferSizeFrames(
+ (unsigned long)(suggestedInputLatency * sampleRate),
+ *hostFramesPerInputBuffer,
+ PA_MME_MIN_HOST_INPUT_BUFFER_COUNT_FULL_DUPLEX_ );
}
}
}
bufferProcessorIsInitialized = 1;
+ /* stream info input latency is the minimum buffering latency (unlike suggested and default which are *maximums*) */
stream->streamRepresentation.streamInfo.inputLatency =
(double)(PaUtil_GetBufferProcessorInputLatencyFrames(&stream->bufferProcessor)
- +(framesPerHostInputBuffer * (hostInputBufferCount-1))) / sampleRate;
+ + framesPerHostInputBuffer) / sampleRate;
stream->streamRepresentation.streamInfo.outputLatency =
(double)(PaUtil_GetBufferProcessorOutputLatencyFrames(&stream->bufferProcessor)
- +(framesPerHostOutputBuffer * (hostOutputBufferCount-1))) / sampleRate;
+ + (framesPerHostOutputBuffer * (hostOutputBufferCount-1))) / sampleRate;
stream->streamRepresentation.streamInfo.sampleRate = sampleRate;
stream->primeStreamUsingCallback = ( (streamFlags&paPrimeOutputBuffersUsingStreamCallback) && streamCallback ) ? 1 : 0;
projects / portaudio / commitdiff