[FFmpeg-devel] [PATCH] avcodec/qpeg: Optimize long runs in qpeg_decode_intra() not spanning a full row

[Michael Niedermayer]

On Mon, Jan 07, 2019 at 07:41:04PM +0100, Paul B Mahol wrote:
> On 1/7/19, Michael Niedermayer <michael at niedermayer.cc> wrote:
> > Fixes: Timeout
> > Fixes:
> > 11354/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_QPEG_fuzzer-5766275943366656
> >
> > Before: Executed
> > clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_QPEG_fuzzer-5766275943366656
> > in 9470 ms
> > After : Executed
> > clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_QPEG_fuzzer-5766275943366656
> > in  134 ms
> >
> > Found-by: continuous fuzzing process
> > https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> > Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> > ---
> >  libavcodec/qpeg.c | 5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/libavcodec/qpeg.c b/libavcodec/qpeg.c
> > index cb452621e7..654fd998d6 100644
> > --- a/libavcodec/qpeg.c
> > +++ b/libavcodec/qpeg.c
> > @@ -80,7 +80,10 @@ static void qpeg_decode_intra(QpegContext *qctx, uint8_t
> > *dst,
> >
> >              p = bytestream2_get_byte(&qctx->buffer);
> >              for(i = 0; i < run; i++) {
> > -                dst[filled++] = p;
> > +                int step = FFMIN(run - i, width - filled);
> > +                memset(dst+filled, p, step);
> > +                filled += step;
> > +                i      += step - 1;
> >                  if (filled >= width) {
> >                      filled = 0;
> >                      dst -= stride;
> > --
> > 2.20.1
> >
> > _______________________________________________
> > ffmpeg-devel mailing list
> > ffmpeg-devel at ffmpeg.org
> > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> >
> 
> lgtm if output does not change.

fate-qpeg passes and it executes this codepath
do you have any other files i should test ?

thx


[...]
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Good people do not need laws to tell them to act responsibly, while bad
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