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pcm/Export: DSD_U32 quarters the sample rate

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DSD_U32 packs four bytes instead of one large "sample", thus the
sample rate is one quarter of the input sample rate.  This fixes a
rather critical DSD_U32 playback problem.
This commit is contained in:
Max Kellermann 2017-01-11 10:06:27 +01:00
parent c143adba91
commit 2b43ceb6c6
3 changed files with 17 additions and 0 deletions
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2
NEWS
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@ -1,6 +1,8 @@
ver 0.20.2 (not yet released) ver 0.20.2 (not yet released)
* decoder * decoder
- flac: add options "probesize" and "analyzeduration" - flac: add options "probesize" and "analyzeduration"
* output
- alsa: fix the DSD_U32 sample rate
ver 0.20.1 (2017/01/09) ver 0.20.1 (2017/01/09)
* input * input

12
src/pcm/PcmExport.cxx
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@ -101,12 +101,24 @@ PcmExport::GetFrameSize(const AudioFormat &audio_format) const
unsigned unsigned
PcmExport::Params::CalcOutputSampleRate(unsigned sample_rate) const PcmExport::Params::CalcOutputSampleRate(unsigned sample_rate) const
{ {
#ifdef ENABLE_DSD
if (dsd_u32)
/* DSD_U32 combines four 8-bit "samples" in one 32-bit
"sample" */
sample_rate /= 4;
#endif
return sample_rate; return sample_rate;
} }
unsigned unsigned
PcmExport::Params::CalcInputSampleRate(unsigned sample_rate) const PcmExport::Params::CalcInputSampleRate(unsigned sample_rate) const
{ {
#ifdef ENABLE_DSD
if (dsd_u32)
sample_rate *= 4;
#endif
return sample_rate; return sample_rate;
} }

3
test/test_pcm_export.cxx
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@ -146,6 +146,9 @@ PcmExportTest::TestDsdU32()
PcmExport::Params params; PcmExport::Params params;
params.dsd_u32 = true; params.dsd_u32 = true;
CPPUNIT_ASSERT_EQUAL(params.CalcOutputSampleRate(705600u), 176400u);
CPPUNIT_ASSERT_EQUAL(params.CalcInputSampleRate(176400u), 705600u);
PcmExport e; PcmExport e;
e.Open(SampleFormat::DSD, 2, params); e.Open(SampleFormat::DSD, 2, params);