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avcodec/ffv1enc: Heuristic to select fixed in float multipliers

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Sponsored-by: Sovereign Tech Fund
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer
2025-03-24 17:33:46 +01:00
parent a33908d051
commit 051fd03f6c
1 changed files with 24 additions and 6 deletions
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30
libavcodec/ffv1enc.c
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@ -1403,17 +1403,30 @@ static void encode_float32_remap(FFV1Context *f, FFV1SliceContext *sc,
s.i = 0; s.i = 0;
s.p = p; s.p = p;
s.mul_count = 1; for(int v = 0; v< 512; v++) {
if (v >= 0x378/8 && v <= 23 + 0x378/8) {
s.mul[v] = -(0x800080 >> (v - 0x378/8));
} else
s.mul[v] = -1;
}
for (int i= 0; i<s.pixel_num; i++) { for (int i= 0; i<s.pixel_num; i++) {
int64_t val = sc->unit[p][i].val; int64_t val = sc->unit[p][i].val;
if (val != last_val) { if (val != last_val) {
av_assert2(last_val < val); av_assert2(last_val < val);
for(int si= 0; si < FF_ARRAY_ELEMS(score_tab); si++) { for(int si= 0; si < FF_ARRAY_ELEMS(score_tab); si++) {
int64_t delta = val - last_val; int64_t delta = val - last_val;
int mul = last_val < 0 ? 1 : (1<<si); int mul;
int64_t cost = FFMAX((delta + mul/2) / mul, 1); int64_t cost;
score_tab[si] += log2(cost) + fabs(delta - cost*mul);
if (last_val < 0) {
mul = 1;
} else if (si + 1 == FF_ARRAY_ELEMS(score_tab)) {
mul = -s.mul[ (last_val + 1) >> (32-9) ];
} else
mul = 1<<si;
cost = FFMAX((delta + mul/2) / mul, 1);
score_tab[si] += log2(cost) + log2(fabs(delta - cost*mul)+1);
} }
last_val = val; last_val = val;
} }
@ -1422,7 +1435,12 @@ static void encode_float32_remap(FFV1Context *f, FFV1SliceContext *sc,
if (score_tab[si] < score_tab[ best_index ]) if (score_tab[si] < score_tab[ best_index ])
best_index = si; best_index = si;
} }
s.mul[0] = -1 << best_index; if (best_index + 1 < FF_ARRAY_ELEMS(score_tab)) {
s.mul[0] = -1 << best_index;
s.mul_count = 1;
} else {
s.mul_count = 512;
}
s.mul[s.mul_count] = 1; s.mul[s.mul_count] = 1;
encode_float32_remap_segment(sc, &s, 1, 1); encode_float32_remap_segment(sc, &s, 1, 1);