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Fix .mul IMA decoding oddness [Tomb Raider Underworld (PC)]

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bnnm 2020-07-11 21:26:12 +02:00
parent 477666a4f7
commit 799f5939b4
1 changed files with 27 additions and 22 deletions
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45
src/coding/ima_decoder.c
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@ -322,11 +322,11 @@ static const int16_t mul_delta_table[16] = {
/* Crystal Dynamics IMA, reverse engineered from the exe, also info: https://github.com/sephiroth99/MulDeMu */
static void cd_ima_expand_nibble(VGMSTREAMCHANNEL* stream, off_t byte_offset, int shift, int32_t* hist1, int32_t* index) {
static void cd_ima_expand_nibble(uint8_t byte, int shift, int32_t* hist1, int32_t* index) {
int code, sample, step, delta;
/* could do the above table calcs during decode too */
code = (read_8bit(byte_offset,stream->streamfile) >> shift) & 0xf;
code = (byte >> shift) & 0xf;
sample = *hist1;
step = mul_adpcm_table[*index];
@ -1210,51 +1210,56 @@ void decode_h4m_ima(VGMSTREAMCHANNEL * stream, sample_t * outbuf, int channelspa
stream->adpcm_step_index = step_index;
}
/* test... */
static inline int _clamp_s32(int value, int min, int max) {
if (value < min)
return min;
else if (value > max)
return max;
else
return value;
}
/* Crystal Dynamics IMA. Original code uses mind-bending intrinsics, so this may not be fully accurate.
* Has another table with delta_table MMX combos, and using header sample and clamps seems necessary. */
* Has another table with delta_table MMX combos, and uses header sample (first nibble is always 0). */
void decode_cd_ima(VGMSTREAMCHANNEL* stream, sample_t* outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do, int channel) {
uint8_t frame[0x24] = {0};
int i, frames_in, sample_pos = 0, block_samples, frame_size;
int32_t hist1 = stream->adpcm_history1_32;
int step_index = stream->adpcm_step_index;
off_t frame_offset;
/* external interleave (fixed size), mono */
block_samples = (0x24 - 0x4) * 2;
frame_size = 0x24;
block_samples = (frame_size - 0x4) * 2;
frames_in = first_sample / block_samples;
first_sample = first_sample % block_samples;
frame_size = 0x24;
frame_offset = stream->offset + frame_size*frames_in;
frame_offset = stream->offset + frame_size * frames_in;
read_streamfile(frame, frame_offset, frame_size, stream->streamfile); /* ignore EOF errors */
/* normal header (hist+step+reserved), mono */
if (first_sample == 0) {
off_t header_offset = frame_offset + 0x00;
hist1 = get_s16le(frame + 0x00);
step_index = get_u8(frame + 0x02);
step_index = _clamp_s32(step_index, 0, 88);
hist1 = read_16bitLE(header_offset+0x00,stream->streamfile);
step_index = read_8bit(header_offset+0x02,stream->streamfile);
if (step_index < 0) step_index=0;
if (step_index > 88) step_index=88;
/* write header sample (even samples per block, skips last nibble) */
/* write header sample (even samples per block, skips first nibble) */
outbuf[sample_pos] = (short)(hist1);
sample_pos += channelspacing;
first_sample += 1;
samples_to_do -= 1;
}
/* decode nibbles (layout: straight in mono ) */
/* decode nibbles (layout: straight in mono) */
for (i = first_sample; i < first_sample + samples_to_do; i++) {
off_t byte_offset = frame_offset + 0x04 + (i-1)/2;
int nibble_shift = (!((i-1)&1) ? 0:4); /* low first */
int pos = 0x04 + (i/2);
int shift = (i&1 ? 4:0); /* low first, but first low nibble is skipped */
/* must skip last nibble per spec, rarely needed though (ex. Gauntlet Dark Legacy) */
if (i < block_samples) {
cd_ima_expand_nibble(stream, byte_offset,nibble_shift, &hist1, &step_index);
cd_ima_expand_nibble(frame[pos], shift, &hist1, &step_index);
outbuf[sample_pos] = (short)(hist1);
sample_pos += channelspacing;
}
}
stream->adpcm_history1_32 = hist1;
stream->adpcm_step_index = step_index;