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* [FFmpeg-devel] [PATCH 1/4] avcodec/j2kenc: Merge dwt_norm into lambda
@ 2024-06-20 19:35 Michael Niedermayer
  2024-06-20 19:35 ` [FFmpeg-devel] [PATCH 2/4] avcodec/utvideoenc: Use unsigned shift to build flags Michael Niedermayer
                   ` (4 more replies)
  0 siblings, 5 replies; 10+ messages in thread
From: Michael Niedermayer @ 2024-06-20 19:35 UTC (permalink / raw)
  To: FFmpeg development discussions and patches

This moves computations out of a loop

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>
---
 libavcodec/j2kenc.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/libavcodec/j2kenc.c b/libavcodec/j2kenc.c
index 8cf82f7216c..91e66d81048 100644
--- a/libavcodec/j2kenc.c
+++ b/libavcodec/j2kenc.c
@@ -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;
-- 
2.45.2

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^ permalink raw reply	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2024-07-16 13:26 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-06-20 19:35 [FFmpeg-devel] [PATCH 1/4] avcodec/j2kenc: Merge dwt_norm into lambda Michael Niedermayer
2024-06-20 19:35 ` [FFmpeg-devel] [PATCH 2/4] avcodec/utvideoenc: Use unsigned shift to build flags Michael Niedermayer
2024-06-20 19:35 ` [FFmpeg-devel] [PATCH 3/4] avcodec/mpeg12enc: Use av_rescale() in vbv_buffer_size computation Michael Niedermayer
2024-06-20 19:35 ` [FFmpeg-devel] [PATCH 4/4] avcodec/mpegvideo_enc: Do not duplicate pictures on shifting Michael Niedermayer
2024-07-14 23:02   ` Michael Niedermayer
2024-06-21  9:38 ` [FFmpeg-devel] [PATCH 1/4] avcodec/j2kenc: Merge dwt_norm into lambda Andreas Rheinhardt
2024-06-21 21:09   ` Michael Niedermayer
2024-07-16 13:25     ` Michael Niedermayer
2024-06-23 22:48   ` Sean McGovern
2024-07-16 13:26 ` Michael Niedermayer

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