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avcodec/j2kenc: Merge dwt_norm into lambda

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This moves computations out of a loop

This may help with UB in vsynth*-jpeg2000-yuva444p16

Fixes: signed integer overflow: 31665934879948800 * 9998 cannot be represented in type 'long'
Fixes: 69024/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_JPEG2000_fuzzer-5949662967169024

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2024-06-19 20:58:05 +02:00
parent 8a4e5e0e15
commit a84fbd7471
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GPG Key ID: B18E8928B3948D64
1 changed files with 5 additions and 4 deletions
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9
libavcodec/j2kenc.c
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@ -1349,7 +1349,7 @@ static void makelayers(Jpeg2000EncoderContext *s, Jpeg2000Tile *tile)
}
}
static int getcut(Jpeg2000Cblk *cblk, uint64_t lambda, int dwt_norm)
static int getcut(Jpeg2000Cblk *cblk, uint64_t lambda)
{
int passno, res = 0;
for (passno = 0; passno < cblk->npasses; passno++){
@ -1361,7 +1361,7 @@ static int getcut(Jpeg2000Cblk *cblk, uint64_t lambda, int dwt_norm)
dd = cblk->passes[passno].disto
- (res ? cblk->passes[res-1].disto : 0);
if (((dd * dwt_norm) >> WMSEDEC_SHIFT) * dwt_norm >= dr * lambda)
if (dd >= dr * lambda)
res = passno+1;
}
return res;
@ -1384,11 +1384,12 @@ static void truncpasses(Jpeg2000EncoderContext *s, Jpeg2000Tile *tile)
Jpeg2000Band *band = reslevel->band + bandno;
Jpeg2000Prec *prec = band->prec + precno;
int64_t dwt_norm = dwt_norms[codsty->transform == FF_DWT53][bandpos][lev] * (int64_t)band->i_stepsize >> 15;
int64_t lambda_prime = av_rescale(s->lambda, 1 << WMSEDEC_SHIFT, dwt_norm * dwt_norm);
for (cblkno = 0; cblkno < prec->nb_codeblocks_height * prec->nb_codeblocks_width; cblkno++){
Jpeg2000Cblk *cblk = prec->cblk + cblkno;
cblk->ninclpasses = getcut(cblk, s->lambda,
(int64_t)dwt_norms[codsty->transform == FF_DWT53][bandpos][lev] * (int64_t)band->i_stepsize >> 15);
cblk->ninclpasses = getcut(cblk, lambda_prime);
cblk->layers[0].data_start = cblk->data;
cblk->layers[0].cum_passes = cblk->ninclpasses;
cblk->layers[0].npasses = cblk->ninclpasses;