diff options
| -rw-r--r-- | audio/decoders/adpcm.cpp | 16 | ||||
| -rw-r--r-- | audio/decoders/adpcm_intern.h | 6 |
2 files changed, 16 insertions, 6 deletions
diff --git a/audio/decoders/adpcm.cpp b/audio/decoders/adpcm.cpp index 535652a0b3..5c96d5245a 100644 --- a/audio/decoders/adpcm.cpp +++ b/audio/decoders/adpcm.cpp @@ -117,13 +117,19 @@ int DVI_ADPCMStream::readBuffer(int16 *buffer, const int numSamples) { int samples; byte data; - assert(numSamples % 2 == 0); + for (samples = 0; samples < numSamples && !_stream->eos() && (_stream->pos() < _endpos); samples++) { + if (_decodedSampleCount == 0) { + data = _stream->readByte(); + _decodedSamples[0] = decodeIMA((data >> 4) & 0x0f, 0); + _decodedSamples[1] = decodeIMA((data >> 0) & 0x0f, _channels == 2 ? 1 : 0); + _decodedSampleCount = 2; + } - for (samples = 0; samples < numSamples && !_stream->eos() && _stream->pos() < _endpos; samples += 2) { - data = _stream->readByte(); - buffer[samples] = decodeIMA((data >> 4) & 0x0f); - buffer[samples + 1] = decodeIMA(data & 0x0f, _channels == 2 ? 1 : 0); + // (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 31747aabaf..537ae023ef 100644 --- a/audio/decoders/adpcm_intern.h +++ b/audio/decoders/adpcm_intern.h @@ -108,9 +108,13 @@ public: class DVI_ADPCMStream : public Ima_ADPCMStream { public: DVI_ADPCMStream(Common::SeekableReadStream *stream, DisposeAfterUse::Flag disposeAfterUse, uint32 size, int rate, int channels, uint32 blockAlign) - : Ima_ADPCMStream(stream, disposeAfterUse, size, rate, channels, blockAlign) {} + : Ima_ADPCMStream(stream, disposeAfterUse, size, rate, channels, blockAlign) { _decodedSampleCount = 0; } virtual int readBuffer(int16 *buffer, const int numSamples); + +private: + uint8 _decodedSampleCount; + int16 _decodedSamples[2]; }; class Apple_ADPCMStream : public Ima_ADPCMStream { |