[FFmpeg-devel] [h264] Make ff_h264_build_ref_list stricter with AV_EF_EXPLODE

[Michael Niedermayer]

On Thu, Aug 07, 2025 at 02:20:11PM -0700, Dale Curtis wrote:
> On Wed, Aug 6, 2025 at 3:05 PM Michael Niedermayer <michael at niedermayer.cc>
[...]
> 
> >
> >
> > >
> > > Signed-off-by: Dale Curtis <dalecurtis at chromium.org>
> > > ---
> > >  libavcodec/h264_refs.c | 7 +++++++
> > >  1 file changed, 7 insertions(+)
> > >
> > > diff --git a/libavcodec/h264_refs.c b/libavcodec/h264_refs.c
> > > index 74840e5909..e6e3adf502 100644
> > > --- a/libavcodec/h264_refs.c
> > > +++ b/libavcodec/h264_refs.c
> > > @@ -370,6 +370,9 @@ int ff_h264_build_ref_list(H264Context *h,
> > H264SliceContext *sl)
> > >                         i < 0 ? "reference picture missing during
> > reorder\n" :
> > >                                 "mismatching reference\n"
> > >                        );
> > > +                if (h->avctx->err_recognition & AV_EF_EXPLODE) {
> > > +                  return AVERROR_INVALIDDATA;
> > > +                }
> >
> > indention depth is 4 in ffmpeg consistently
> >
> 
> Done.
> 
> 
> >
> >
> > >                  memset(&sl->ref_list[list][index], 0,
> > sizeof(sl->ref_list[0][0])); // FIXME
> > >              } else {
> > >                  for (i = index; i + 1 < sl->ref_count[list]; i++) {
> > > @@ -392,6 +395,10 @@ int ff_h264_build_ref_list(H264Context *h,
> > H264SliceContext *sl)
> > >          for (int index = 0; index < sl->ref_count[list]; index++) {
> > >              if (   !sl->ref_list[list][index].parent
> > >                  || (!FIELD_PICTURE(h) &&
> > (sl->ref_list[list][index].reference&3) != 3)) {
> > > +                if (h->avctx->err_recognition & AV_EF_EXPLODE) {
> > > +                  av_log(h->avctx, AV_LOG_ERROR, "Missing reference
> > picture\n");
> > > +                  return AVERROR_INVALIDDATA;
> > > +                }
> > >                  av_log(h->avctx, AV_LOG_ERROR, "Missing reference
> > picture, default is %d\n", h->default_ref[list].poc);
> >
> > the error out can be after this av_log() avoiding the 2nd av_log() in the
> > if()
> >
> 
> I didn't make this change, but can if you prefer. The existing log implies
> a default is set, but the new log simply indicates the reference picture
> missing is a fatal error.

ok, i will apply this with a commit message not refering to
ff_put_h264_chroma_mc4_ssse3()
AV_EF_EXPLODE is not a fix for a issue with MC

thx

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Opposition brings concord. Out of discord comes the fairest harmony.
-- Heraclitus
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