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Fix Circus VQ filtering in some files

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This commit is contained in:
bnnm 2020-03-08 00:34:20 +01:00
parent a125d9c0fa
commit 241406c788
1 changed files with 9 additions and 9 deletions
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18
src/coding/circus_decoder_lib.c
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@ -77,19 +77,20 @@ static void convert(uint8_t flags, int32_t* invbuf, int16_t* pcmbuf, int* p_hist
hist1 = *p_hist1;
hist2 = *p_hist2;
/* some ops below would use SHRs (>>), but there is some rounding in the
* original ASM that decompiles and I think corresponds do DIVs
* (right shift and divs of negative values isn't equivalent) */
/* some ops below would use SHRs (>>), but there is some rounding in the original
* ASM that decompiles and I think corresponds do DIVs (right shift and divs of
* negative values isn't equivalent). Similarly the filters seem to use CDQ tricks
* to simulate s64 ops, but I'm not sure casting is 100% equivalent (sounds ok tho). */
/* do final filtering and conversion to PCM */
for (i = 0; i < XPCM_FRAME_SAMPLES_ALL + XPCM_FRAME_OVERLAP_ALL; i++) {
sample = *invbuf++;
if (flags & 0x10)
sample = 3 * sample / 2; // (3 * sample) >> 2
sample /= 1024; //sample >>= 10;
sample = (3 * (int64_t)sample / 2) / 1024; //>> 10;
else
sample = sample / 1024; //>> 10;
sample = ((3 * sample + 8 * 3 * sample + 4 * hist1 + hist2) << 11);
sample /= 65536; // sample >>= 16;
sample = ((27 * (int64_t)sample + 4 * hist1 + hist2) << 11) / 65536; //>> 16
hist2 = hist1;
hist1 = sample;
@ -97,8 +98,7 @@ static void convert(uint8_t flags, int32_t* invbuf, int16_t* pcmbuf, int* p_hist
/* last 32 decoded samples aren't output, but are used next frame to overlap
* with beginning samples (filters(?) windowing, not too noticeable though) */
if (i < XPCM_FRAME_OVERLAP_ALL && frame > 0) {
sample = (i * sample) + ((XPCM_FRAME_OVERLAP_ALL - i) * pcmbuf[XPCM_FRAME_SAMPLES_ALL + i]);
sample /= 32; //sample >>= 5
sample = ((i * (int64_t)sample) + ((XPCM_FRAME_OVERLAP_ALL - i) * pcmbuf[XPCM_FRAME_SAMPLES_ALL + i])) / 32; //>> 5
}
if (sample > 32767)