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VIDEO: Fix audio stereo decoding.

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The differential PCM is applied for each channel independently
This commit is contained in:
Le Philousophe 2022-01-08 21:49:19 +01:00
parent 97b474e78a
commit 3f01f8301c
2 changed files with 37 additions and 19 deletions
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53
video/hnm_decoder.cpp
View File

@ -572,7 +572,7 @@ void HNMDecoder::HNM5VideoTrack::decodeFrame(Common::SeekableReadStream *stream,
HNMDecoder::DPCMAudioTrack::DPCMAudioTrack(uint16 format, uint16 bits, uint sampleRate, bool stereo,
Audio::Mixer::SoundType soundType) : AudioTrack(soundType), _audioStream(nullptr),
_gotLUT(false), _lastSample(0), _sampleRate(sampleRate), _stereo(stereo) {
_gotLUT(false), _lastSampleL(0), _lastSampleR(0), _sampleRate(sampleRate), _stereo(stereo) {
if (bits != 16) {
error("Unsupported audio bits");
}
@ -603,28 +603,45 @@ Audio::Timestamp HNMDecoder::DPCMAudioTrack::decodeSound(
_gotLUT = true;
}
if (size > 0) {
uint16 *out = (uint16 *)malloc(size * sizeof(*out));
uint16 *p = out;
uint16 sample = _lastSample;
if (size == 0) {
return Audio::Timestamp(0, 0, _sampleRate);
}
uint16 *out = (uint16 *)malloc(size * sizeof(*out));
uint16 *p = out;
byte flags = Audio::FLAG_16BITS;
#ifdef SCUMM_LITTLE_ENDIAN
flags |= Audio::FLAG_LITTLE_ENDIAN;
#endif
if (_audioStream->isStereo()) {
uint16 sampleL = _lastSampleL;
uint16 sampleR = _lastSampleR;
byte deltaId;
for (uint32 i = 0; i < size / 2; i++, p += 2) {
deltaId = stream->readByte();
sampleL += _lut[deltaId];
deltaId = stream->readByte();
sampleR += _lut[deltaId];
p[0] = sampleL;
p[1] = sampleR;
}
_lastSampleL = sampleL;
_lastSampleR = sampleR;
flags |= Audio::FLAG_STEREO;
} else {
uint16 sample = _lastSampleL;
byte deltaId;
for (uint32 i = 0; i < size; i++, p++) {
byte deltaId = stream->readByte();
deltaId = stream->readByte();
sample += _lut[deltaId];
*p = sample;
}
_lastSample = sample;
byte flags = Audio::FLAG_16BITS;
if (_audioStream->isStereo())
flags |= Audio::FLAG_STEREO;
#ifdef SCUMM_LITTLE_ENDIAN
flags |= Audio::FLAG_LITTLE_ENDIAN;
#endif
_audioStream->queueBuffer((byte *)out, size * sizeof(*out), DisposeAfterUse::YES, flags);
_lastSampleL = sample;
}
_audioStream->queueBuffer((byte *)out, size * sizeof(*out), DisposeAfterUse::YES, flags);
return Audio::Timestamp(0, _audioStream->isStereo() ? size / 2 : size, _sampleRate);
}

3
video/hnm_decoder.h
View File

@ -152,7 +152,8 @@ private:
Audio::QueuingAudioStream *_audioStream;
bool _gotLUT;
uint16 _lut[256];
uint16 _lastSample;
uint16 _lastSampleL;
uint16 _lastSampleR;
uint _sampleRate;
bool _stereo;
};