On Mon, Jul 14, 2025 at 08:52:30PM +0200, Michael Niedermayer wrote: > On Sun, Jul 13, 2025 at 07:34:50PM +0200, Andreas Rheinhardt wrote: > > Michael Niedermayer: > > > Fixes: out of array read in the chroma plane > > > Fixes: > > > 428034092/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MPEG4_DEC_fuzzer-5582608941776896.test > > > > > > Found-by: continuous fuzzing process > > > https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg > > > Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> > > > --- > > > libavcodec/mpegvideo_dec.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/libavcodec/mpegvideo_dec.c b/libavcodec/mpegvideo_dec.c > > > index 4a54f6cd614..85e24c667e3 100644 > > > --- a/libavcodec/mpegvideo_dec.c > > > +++ b/libavcodec/mpegvideo_dec.c > > > @@ -557,7 +557,7 @@ static av_always_inline void > > > mpeg_motion_lowres(MpegEncContext *s, > > > ptr_cr = ref_picture[2] + uvsrc_y * uvlinesize + uvsrc_x; > > > > > > if ((unsigned) src_x > FFMAX( h_edge_pos - (!!sx) - 2 * block_s, > > > 0) || uvsrc_y<0 || > > > - (unsigned) src_y > FFMAX((v_edge_pos >> field_based) - (!!sy) - > > > FFMAX(h, hc<<s->chroma_y_shift), 0)) { > > > + (unsigned) src_y > FFMAX((v_edge_pos >> field_based) - (!!sy) - > > > FFMAX(h, field_select + hc<<s->chroma_y_shift), 0)) { > > > s->vdsp.emulated_edge_mc(s->sc.edge_emu_buffer, ptr_y, > > > linesize >> field_based, linesize >> > > > field_based, > > > 17, 17 + field_based, > > > > Is lowres actually used for mpegvideo-decoders at all (in 2025)? > > why not ? > > Example: making thumbnails of videos. > If a video can be decoded in 2min instead of 3min that still allows to scan > it sooner for potential thumbnails
ok if i apply this ? or you want me to wait ? iam happy to wait if you want to review/analyze thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Avoid a single point of failure, be that a person or equipment.
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