diff options
Diffstat (limited to 'audio')
| -rw-r--r-- | audio/decoders/adpcm.cpp | 55 | ||||
| -rw-r--r-- | audio/decoders/adpcm_intern.h | 7 |
2 files changed, 35 insertions, 27 deletions
diff --git a/audio/decoders/adpcm.cpp b/audio/decoders/adpcm.cpp index 2fe509e1f3..f069ee3417 100644 --- a/audio/decoders/adpcm.cpp +++ b/audio/decoders/adpcm.cpp @@ -268,7 +268,6 @@ static const int MSADPCMAdaptationTable[] = { 768, 614, 512, 409, 307, 230, 230, 230 }; - int16 MS_ADPCMStream::decodeMS(ADPCMChannelStatus *c, byte code) { int32 predictor; @@ -290,40 +289,42 @@ int16 MS_ADPCMStream::decodeMS(ADPCMChannelStatus *c, byte code) { int MS_ADPCMStream::readBuffer(int16 *buffer, const int numSamples) { int samples; byte data; - int i = 0; - - samples = 0; + int i; - while (samples < numSamples && !_stream->eos() && _stream->pos() < _endpos) { - if (_blockPos[0] == _blockAlign) { - // read block header - for (i = 0; i < _channels; i++) { - _status.ch[i].predictor = CLIP(_stream->readByte(), (byte)0, (byte)6); - _status.ch[i].coeff1 = MSADPCMAdaptCoeff1[_status.ch[i].predictor]; - _status.ch[i].coeff2 = MSADPCMAdaptCoeff2[_status.ch[i].predictor]; - } + for (samples = 0; samples < numSamples && !endOfData(); samples++) { + if (_decodedSampleCount == 0) { + if (_blockPos[0] == _blockAlign) { + // read block header + for (i = 0; i < _channels; i++) { + _status.ch[i].predictor = CLIP(_stream->readByte(), (byte)0, (byte)6); + _status.ch[i].coeff1 = MSADPCMAdaptCoeff1[_status.ch[i].predictor]; + _status.ch[i].coeff2 = MSADPCMAdaptCoeff2[_status.ch[i].predictor]; + } - for (i = 0; i < _channels; i++) - _status.ch[i].delta = _stream->readSint16LE(); + for (i = 0; i < _channels; i++) + _status.ch[i].delta = _stream->readSint16LE(); - for (i = 0; i < _channels; i++) - _status.ch[i].sample1 = _stream->readSint16LE(); + for (i = 0; i < _channels; i++) + _status.ch[i].sample1 = _stream->readSint16LE(); - for (i = 0; i < _channels; i++) - buffer[samples++] = _status.ch[i].sample2 = _stream->readSint16LE(); + for (i = 0; i < _channels; i++) + _decodedSamples[_decodedSampleCount++] = _status.ch[i].sample2 = _stream->readSint16LE(); - for (i = 0; i < _channels; i++) - buffer[samples++] = _status.ch[i].sample1; + for (i = 0; i < _channels; i++) + _decodedSamples[_decodedSampleCount++] = _status.ch[i].sample1; - _blockPos[0] = _channels * 7; + _blockPos[0] = _channels * 7; + } else { + data = _stream->readByte(); + _blockPos[0]++; + _decodedSamples[_decodedSampleCount++] = decodeMS(&_status.ch[0], (data >> 4) & 0x0f); + _decodedSamples[_decodedSampleCount++] = decodeMS(&_status.ch[_channels - 1], data & 0x0f); + } } - for (; samples < numSamples && _blockPos[0] < _blockAlign && !_stream->eos() && _stream->pos() < _endpos; samples += 2) { - data = _stream->readByte(); - _blockPos[0]++; - buffer[samples] = decodeMS(&_status.ch[0], (data >> 4) & 0x0f); - buffer[samples + 1] = decodeMS(&_status.ch[_channels - 1], data & 0x0f); - } + // (1 - (count - 1)) ensures that _decodedSamples acts as a FIFO of depth 2 + buffer[samples] = _decodedSamples[1 - (_decodedSampleCount - 1)]; + _decodedSampleCount--; } return samples; diff --git a/audio/decoders/adpcm_intern.h b/audio/decoders/adpcm_intern.h index 3b8d8c74d0..66a1aa605f 100644 --- a/audio/decoders/adpcm_intern.h +++ b/audio/decoders/adpcm_intern.h @@ -206,12 +206,19 @@ public: if (blockAlign == 0) error("MS_ADPCMStream(): blockAlign isn't specified for MS ADPCM"); memset(&_status, 0, sizeof(_status)); + _decodedSampleCount = 0; } + virtual bool endOfData() const { return (_stream->eos() || _stream->pos() >= _endpos) && (_decodedSampleCount == 0); } + virtual int readBuffer(int16 *buffer, const int numSamples); protected: int16 decodeMS(ADPCMChannelStatus *c, byte); + +private: + uint8 _decodedSampleCount; + int16 _decodedSamples[4]; }; // Duck DK3 IMA ADPCM Decoder |