70 lines
1.9 KiB
C++
70 lines
1.9 KiB
C++
#pragma once
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#include "bitfield.h"
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#include "types.h"
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namespace CDXA {
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enum
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{
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XA_SUBHEADER_SIZE = 4,
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XA_ADPCM_SAMPLES_PER_SECTOR_4BIT = 4032, // 28 words * 8 nibbles per word * 18 chunks
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XA_ADPCM_SAMPLES_PER_SECTOR_8BIT = 2016 // 28 words * 4 bytes per word * 18 chunks
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};
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struct XASubHeader
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{
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u8 file_number;
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u8 channel_number;
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union Submode
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{
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u8 bits;
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BitField<u8, bool, 0, 1> eor;
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BitField<u8, bool, 1, 1> video;
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BitField<u8, bool, 2, 1> audio;
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BitField<u8, bool, 3, 1> data;
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BitField<u8, bool, 4, 1> trigger;
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BitField<u8, bool, 5, 1> form2;
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BitField<u8, bool, 6, 1> realtime;
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BitField<u8, bool, 7, 1> eof;
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} submode;
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union Codinginfo
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{
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u8 bits;
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BitField<u8, u8, 0, 2> mono_stereo;
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BitField<u8, u8, 2, 2> sample_rate;
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BitField<u8, u8, 4, 2> bits_per_sample;
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BitField<u8, bool, 6, 1> emphasis;
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bool IsStereo() const { return mono_stereo == 1; }
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bool IsHalfSampleRate() const { return sample_rate == 1; }
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u32 GetSampleRate() const { return sample_rate == 1 ? 18900 : 37800; }
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u32 GetBitsPerSample() const { return bits_per_sample == 1 ? 8 : 4; }
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u32 GetSamplesPerSector() const
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{
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return bits_per_sample == 1 ? XA_ADPCM_SAMPLES_PER_SECTOR_8BIT : XA_ADPCM_SAMPLES_PER_SECTOR_4BIT;
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}
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} codinginfo;
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};
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union XA_ADPCMBlockHeader
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{
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u8 bits;
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BitField<u8, u8, 0, 4> shift;
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BitField<u8, u8, 4, 2> filter;
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// For both 4bit and 8bit ADPCM, reserved shift values 13..15 will act same as shift=9).
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u8 GetShift() const
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{
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const u8 shift_value = shift;
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return (shift_value > 12) ? 9 : shift_value;
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}
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u8 GetFilter() const { return filter; }
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};
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static_assert(sizeof(XA_ADPCMBlockHeader) == 1, "XA-ADPCM block header is one byte");
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// Decodes XA-ADPCM samples in an audio sector. Stereo samples are interleaved with left first.
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void DecodeADPCMSector(const void* data, s16* samples, s32* last_samples);
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} // namespace CDXA
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