diff options
Diffstat (limited to 'audio/decoders/adpcm.cpp')
-rw-r--r-- | audio/decoders/adpcm.cpp | 71 |
1 files changed, 29 insertions, 42 deletions
diff --git a/audio/decoders/adpcm.cpp b/audio/decoders/adpcm.cpp index ac18b244c5..3b53ca2fd1 100644 --- a/audio/decoders/adpcm.cpp +++ b/audio/decoders/adpcm.cpp @@ -201,60 +201,49 @@ int Apple_ADPCMStream::readBuffer(int16 *buffer, const int numSamples) { return samples[0] + samples[1]; } + #pragma mark - -int MSIma_ADPCMStream::readBufferMSIMA1(int16 *buffer, const int numSamples) { - int samples = 0; - byte data; +int MSIma_ADPCMStream::readBuffer(int16 *buffer, const int numSamples) { + // Need to write at least one sample per channel + assert((numSamples % _channels) == 0); - assert(numSamples % 2 == 0); + int samples = 0; while (samples < numSamples && !_stream->eos() && _stream->pos() < _endpos) { if (_blockPos[0] == _blockAlign) { - // read block header - _status.ima_ch[0].last = _stream->readSint16LE(); - _status.ima_ch[0].stepIndex = _stream->readSint16LE(); - _blockPos[0] = 4; - } + for (int i = 0; i < _channels; i++) { + // read block header + _status.ima_ch[i].last = _stream->readSint16LE(); + _status.ima_ch[i].stepIndex = _stream->readSint16LE(); + } - for (; samples < numSamples && _blockPos[0] < _blockAlign && !_stream->eos() && _stream->pos() < _endpos; samples += 2) { - data = _stream->readByte(); - _blockPos[0]++; - buffer[samples] = decodeIMA(_invertSamples ? (data >> 4) & 0x0f : data & 0x0f); - buffer[samples + 1] = decodeIMA(_invertSamples ? data & 0x0f : (data >> 4) & 0x0f); + _blockPos[0] = _channels * 4; } - } - return samples; -} + // Decode a set of samples + for (int i = 0; i < _channels; i++) { + // The stream encodes four bytes per channel at a time + for (int j = 0; j < 4; j++) { + byte data = _stream->readByte(); + _blockPos[0]++; + _buffer[i][j * 2] = decodeIMA(data & 0x0f, i); + _buffer[i][j * 2 + 1] = decodeIMA((data >> 4) & 0x0f, i); + _samplesLeft[i] += 2; + } + } -// Microsoft as usual tries to implement it differently. This method -// is used for stereo data. -int MSIma_ADPCMStream::readBufferMSIMA2(int16 *buffer, const int numSamples) { - int samples; - uint32 data; - int nibble; - byte k; - - // TODO: Currently this implementation only supports - // reading a multiple of 16 samples at once. We might - // consider changing that so it could read an arbitrary - // sample pair count. - assert(numSamples % 16 == 0); - - for (samples = 0; samples < numSamples && !_stream->eos() && _stream->pos() < _endpos;) { - for (int channel = 0; channel < 2; channel++) { - data = _stream->readUint32LE(); - - for (nibble = 0; nibble < 8; nibble++) { - k = ((data & 0xf0000000) >> 28); - buffer[samples + channel + nibble * 2] = decodeIMA(k); - data <<= 4; + while (samples < numSamples && _samplesLeft[0] != 0) { + for (int i = 0; i < _channels; i++) { + buffer[samples] = _buffer[i][8 - _samplesLeft[i]]; + _samplesLeft[i]--; } + + samples += _channels; } - samples += 16; } + return samples; } @@ -449,8 +438,6 @@ RewindableAudioStream *makeADPCMStream(Common::SeekableReadStream *stream, Dispo return new Oki_ADPCMStream(stream, disposeAfterUse, size, rate, channels, blockAlign); case kADPCMMSIma: return new MSIma_ADPCMStream(stream, disposeAfterUse, size, rate, channels, blockAlign); - case kADPCMMSImaLastExpress: - return new MSIma_ADPCMStream(stream, disposeAfterUse, size, rate, channels, blockAlign, true); case kADPCMMS: return new MS_ADPCMStream(stream, disposeAfterUse, size, rate, channels, blockAlign); case kADPCMDVI: |