diff options
Diffstat (limited to 'engines/lastexpress')
| -rw-r--r-- | engines/lastexpress/data/snd.cpp | 37 |
1 files changed, 35 insertions, 2 deletions
diff --git a/engines/lastexpress/data/snd.cpp b/engines/lastexpress/data/snd.cpp index bd2320726a..6389489abb 100644 --- a/engines/lastexpress/data/snd.cpp +++ b/engines/lastexpress/data/snd.cpp @@ -30,12 +30,45 @@ #include "lastexpress/debug.h" -#include "audio/decoders/adpcm.h" +#include "audio/decoders/adpcm_intern.h" #include "audio/audiostream.h" #include "common/memstream.h" namespace LastExpress { +// Last Express ADPCM is similar to MS IMA mono, but inverts its nibbles +// and does not have the 4 byte per channel requirement + +class LastExpress_ADPCMStream : public Audio::Ima_ADPCMStream { +public: + LastExpress_ADPCMStream(Common::SeekableReadStream *stream, DisposeAfterUse::Flag disposeAfterUse, uint32 size, uint32 blockSize) : + Audio::Ima_ADPCMStream(stream, disposeAfterUse, size, 44100, 1, blockSize) {} + + int readBuffer(int16 *buffer, const int numSamples) { + int samples = 0; + + assert(numSamples % 2 == 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 (; samples < numSamples && _blockPos[0] < _blockAlign && !_stream->eos() && _stream->pos() < _endpos; samples += 2) { + byte data = _stream->readByte(); + _blockPos[0]++; + buffer[samples] = decodeIMA((data >> 4) & 0x0f); + buffer[samples + 1] = decodeIMA(data & 0x0f); + } + } + + return samples; + } +}; + ////////////////////////////////////////////////////////////////////////// // Sound ////////////////////////////////////////////////////////////////////////// @@ -60,7 +93,7 @@ void SimpleSound::loadHeader(Common::SeekableReadStream *in) { } Audio::AudioStream *SimpleSound::makeDecoder(Common::SeekableReadStream *in, uint32 size) const { - return Audio::makeADPCMStream(in, DisposeAfterUse::YES, size, Audio::kADPCMMSImaLastExpress, 44100, 1, _blockSize); + return new LastExpress_ADPCMStream(in, DisposeAfterUse::YES, size, _blockSize); } void SimpleSound::play(Audio::AudioStream *as) { |