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Improve Level 5 0x555 codec performance

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bnnm 2020-07-31 17:13:22 +02:00
parent 7073d8997d
commit ef64005418
1 changed files with 42 additions and 31 deletions
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73
src/coding/l5_555_decoder.c
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@ -8,48 +8,59 @@ static const int32_t l5_scales[32] = {
0x00130B82, 0x00182B83, 0x001EAC92, 0x0026EDB2, 0x00316777, 0x003EB2E6, 0x004F9232, 0x0064FBD1
};
void decode_l5_555(VGMSTREAMCHANNEL * stream, sample * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do) {
int i=first_sample;
int32_t sample_count;
void decode_l5_555(VGMSTREAMCHANNEL* stream, sample_t* outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do) {
uint8_t frame[0x12] = {0};
off_t frame_offset;
int i, frames_in, sample_count = 0;
size_t bytes_per_frame, samples_per_frame;
uint16_t header;
uint8_t coef_index;
int framesin = first_sample/32;
uint16_t header = (uint16_t)read_16bitLE(framesin*0x12+stream->offset,stream->streamfile);
int32_t pos_scale = l5_scales[(header>>5)&0x1f];
int32_t neg_scale = l5_scales[header&0x1f];
int coef_index = (header >> 10) & 0x1f;
int16_t hist1 = stream->adpcm_history1_16;
int16_t hist2 = stream->adpcm_history2_16;
int16_t hist3 = stream->adpcm_history3_16;
int32_t coef1 = stream->adpcm_coef_3by32[coef_index*3];
int32_t coef2 = stream->adpcm_coef_3by32[coef_index*3+1];
int32_t coef3 = stream->adpcm_coef_3by32[coef_index*3+2];
/*printf("offset: %x\nscale: %d\nindex: %d (%lf,%lf)\nhist: %d %d\n",
(unsigned)stream->offset,scale,coef_index,coef1/2048.0,coef2/2048.0,hist1,hist2);*/
int32_t coef1, coef2, coef3;
int32_t pos_scale, neg_scale;
first_sample = first_sample%32;
/* external interleave (fixed size), mono */
bytes_per_frame = 0x12;
samples_per_frame = (bytes_per_frame - 0x02) * 2; /* always 32 */
frames_in = first_sample / samples_per_frame;
first_sample = first_sample % samples_per_frame;
for (i=first_sample,sample_count=0; i<first_sample+samples_to_do; i++,sample_count+=channelspacing) {
int sample_byte = read_8bit(framesin*0x12+stream->offset+2+i/2,stream->streamfile);
int nibble = (i&1?
get_low_nibble_signed(sample_byte):
get_high_nibble_signed(sample_byte));
int32_t prediction =
-(hist1 * coef1 + hist2 * coef2 + hist3 * coef3);
/* parse frame header */
frame_offset = stream->offset + bytes_per_frame * frames_in;
read_streamfile(frame, frame_offset, bytes_per_frame, stream->streamfile); /* ignore EOF errors */
header = get_u32le(frame);
coef_index = (header >> 10) & 0x1f;
pos_scale = l5_scales[(header >> 5) & 0x1f];
neg_scale = l5_scales[(header >> 0) & 0x1f];
if (nibble >= 0)
{
outbuf[sample_count] = clamp16((prediction + nibble * pos_scale) >> 12);
}
coef1 = stream->adpcm_coef_3by32[coef_index * 3 + 0];
coef2 = stream->adpcm_coef_3by32[coef_index * 3 + 1];
coef3 = stream->adpcm_coef_3by32[coef_index * 3 + 2];
for (i = first_sample; i < first_sample + samples_to_do; i++) {
int32_t prediction, sample = 0;
uint8_t nibbles = frame[0x02 + i/2];
sample = (i&1) ?
get_low_nibble_signed(nibbles):
get_high_nibble_signed(nibbles);
prediction = -(hist1 * coef1 + hist2 * coef2 + hist3 * coef3);
if (sample >= 0)
sample = (prediction + sample * pos_scale) >> 12;
else
{
outbuf[sample_count] = clamp16((prediction + nibble * neg_scale) >> 12);
}
sample = (prediction + sample * neg_scale) >> 12;
sample = clamp16(sample);
outbuf[sample_count] = sample;
sample_count += channelspacing;
hist3 = hist2;
hist2 = hist1;
hist1 = outbuf[sample_count];
hist1 = sample;
}
stream->adpcm_history1_16 = hist1;