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Fix SrcBufferSize calculation when downsampling

master
Chris Robinson 2020-06-29 12:16:30 -07:00
parent 88ad84edf6
commit 775187788a
1 changed files with 36 additions and 20 deletions
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56
alc/voice.cpp
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@ -631,31 +631,47 @@ void Voice::mix(const State vstate, ALCcontext *Context, const ALuint SamplesToD
do {
/* Figure out how many buffer samples will be needed */
ALuint DstBufferSize{SamplesToDo - OutPos};
ALuint SrcBufferSize;
/* Calculate the last written dst sample pos. */
uint64_t DataSize64{DstBufferSize - 1};
/* Calculate the last read src sample pos. */
DataSize64 = (DataSize64*increment + DataPosFrac) >> FRACTIONBITS;
/* +1 to get the src sample count, include padding. */
DataSize64 += 1 + MAX_RESAMPLER_PADDING;
auto SrcBufferSize = static_cast<ALuint>(
minu64(DataSize64, BUFFERSIZE + MAX_RESAMPLER_PADDING + 1));
if(SrcBufferSize > BUFFERSIZE + MAX_RESAMPLER_PADDING)
if(increment <= FRACTIONONE)
{
SrcBufferSize = BUFFERSIZE + MAX_RESAMPLER_PADDING;
/* If the source buffer got saturated, we can't fill the desired
* dst size. Figure out how many samples we can actually mix from
* this.
/* Calculate the last written dst sample pos. */
uint64_t DataSize64{DstBufferSize - 1};
/* Calculate the last read src sample pos. */
DataSize64 = (DataSize64*increment + DataPosFrac) >> FRACTIONBITS;
/* +1 to get the src sample count, include padding. */
DataSize64 += 1 + MAX_RESAMPLER_PADDING;
/* Result is guaranteed to be <= BUFFERSIZE+MAX_RESAMPLER_PADDING
* since we won't use more src samples than dst samples+padding.
*/
DataSize64 = SrcBufferSize - MAX_RESAMPLER_PADDING;
DataSize64 = ((DataSize64<<FRACTIONBITS) - DataPosFrac + increment-1) / increment;
if(DataSize64 < DstBufferSize)
SrcBufferSize = static_cast<ALuint>(DataSize64);
}
else
{
uint64_t DataSize64{DstBufferSize};
/* Calculate the end src sample pos, include padding. */
DataSize64 = (DataSize64*increment + DataPosFrac) >> FRACTIONBITS;
DataSize64 += MAX_RESAMPLER_PADDING;
SrcBufferSize = static_cast<ALuint>(minu64(DataSize64,
BUFFERSIZE + MAX_RESAMPLER_PADDING + 1));
if(SrcBufferSize > BUFFERSIZE + MAX_RESAMPLER_PADDING)
{
/* Some mixers require being 16-byte aligned, so also limit to
* a multiple of 4 samples to maintain alignment.
SrcBufferSize = BUFFERSIZE + MAX_RESAMPLER_PADDING;
/* If the source size got saturated, we can't fill the desired
* dst size. Figure out how many samples we can actually mix
* from this.
*/
DstBufferSize = static_cast<ALuint>(DataSize64) & ~3u;
DataSize64 = SrcBufferSize - MAX_RESAMPLER_PADDING;
DataSize64 = ((DataSize64<<FRACTIONBITS) - DataPosFrac + increment-1) / increment;
if(DataSize64 < DstBufferSize)
{
/* Some mixers require being 16-byte aligned, so also limit
* to a multiple of 4 samples to maintain alignment.
*/
DstBufferSize = static_cast<ALuint>(DataSize64) & ~3u;
}
}
}