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Code Issues Releases Activity

avcodec/cfhd: use LUT for 9 and 18 codebook decompanding

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Also fix codebook 9 decompanding, fixing artifact with codebook 9
samples. Reused Gagandeep Singh patch.
This commit is contained in:
Paul B Mahol 2020-08-03 09:33:36 +02:00
parent b4ae780693
commit 05e58ce4e2
2 changed files with 27 additions and 10 deletions
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35
libavcodec/cfhd.c
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@ -46,6 +46,27 @@ static av_cold int cfhd_init(AVCodecContext *avctx)
s->avctx = avctx;
for (int i = 0; i < 64; i++) {
int val = i;
if (val >= 40) {
if (val >= 54) {
val -= 54;
val <<= 2;
val += 54;
}
val -= 40;
val <<= 2;
val += 40;
}
s->lut[0][i] = val;
}
for (int i = 0; i < 256; i++)
s->lut[1][i] = i + ((768 * i * i * i) / (256 * 256 * 256));
return ff_cfhd_init_vlcs(s);
}
@ -83,16 +104,10 @@ static void init_frame_defaults(CFHDContext *s)
init_peak_table_defaults(s);
}
/* TODO: merge with VLC tables or use LUT */
static inline int dequant_and_decompand(int level, int quantisation, int codebook)
static inline int dequant_and_decompand(CFHDContext *s, int level, int quantisation, int codebook)
{
if (codebook == 0 || codebook == 1) {
int64_t abslevel = abs(level);
if (abslevel < 256)
return (abslevel + ((768 * abslevel * abslevel * abslevel) / (256 * 256 * 256))) *
FFSIGN(level) * quantisation;
else
return level * quantisation;
return s->lut[codebook][abs(level)] * FFSIGN(level) * quantisation;
} else
return level * quantisation;
}
@ -708,7 +723,7 @@ static int cfhd_decode(AVCodecContext *avctx, void *data, int *got_frame,
if (count > expected)
break;
coeff = dequant_and_decompand(level, s->quantisation, 0);
coeff = dequant_and_decompand(s, level, s->quantisation, 0);
for (i = 0; i < run; i++)
*coeff_data++ = coeff;
}
@ -727,7 +742,7 @@ static int cfhd_decode(AVCodecContext *avctx, void *data, int *got_frame,
if (count > expected)
break;
coeff = dequant_and_decompand(level, s->quantisation, s->codebook);
coeff = dequant_and_decompand(s, level, s->quantisation, s->codebook);
for (i = 0; i < run; i++)
*coeff_data++ = coeff;
}

2
libavcodec/cfhd.h
View File

@ -136,6 +136,8 @@ typedef struct CFHDContext {
CFHD_RL_VLC_ELEM table_18_rl_vlc[4572];
VLC vlc_18;
int lut[2][256];
GetBitContext gb;
int coded_width;