[FFmpeg-devel] [PATCH 1/3] Check for missing reference frames in bink decoder.

[Michael Niedermayer]

On Tue, Sep 27, 2011 at 11:42:27PM +0200, Laurent Aimar wrote:
> On Tue, Sep 27, 2011 at 03:49:42AM +0200, Michael Niedermayer wrote:
> > On Tue, Sep 27, 2011 at 01:02:15AM +0200, fenrir at elivagar.org wrote:
> > > From: Laurent Aimar <fenrir at videolan.org>
> > > 
> > > ---
> > >  libavcodec/bink.c |   16 ++++++++++++++++
> > >  1 files changed, 16 insertions(+), 0 deletions(-)
> > > 
> > > diff --git a/libavcodec/bink.c b/libavcodec/bink.c
> > > index e137312..045cd46 100644
> > > --- a/libavcodec/bink.c
> > > +++ b/libavcodec/bink.c
> > > @@ -992,6 +992,10 @@ static int bink_decode_plane(BinkContext *c, GetBitContext *gb, int plane_idx,
> > >              }
> > >              switch (blk) {
> > >              case SKIP_BLOCK:
> > > +                if (!c->last.data[0]) {
> > > +                    av_log(c->avctx, AV_LOG_ERROR, "Missing reference frame\n");
> > > +                    return -1;
> > > +                }
> > >                  c->dsp.put_pixels_tab[1][0](dst, prev, stride, 8);
> > >                  break;
> > >              case SCALED_BLOCK:
> > > @@ -1055,6 +1059,10 @@ static int bink_decode_plane(BinkContext *c, GetBitContext *gb, int plane_idx,
> > >                  prev += 8;
> > >                  break;
> > >              case MOTION_BLOCK:
> > > +                if (!c->last.data[0]) {
> > > +                    av_log(c->avctx, AV_LOG_ERROR, "Missing reference frame\n");
> > > +                    return -1;
> > > +                }
> > >                  xoff = get_value(c, BINK_SRC_X_OFF);
> > >                  yoff = get_value(c, BINK_SRC_Y_OFF);
> > >                  ref = prev + xoff + yoff * stride;
> > 
> > I think its better to skip the block and continue instead of aborting
> > This would allow partially decoding the frame unless i miss something
> > 
> > Another, maybe easier alternative would be allocating a dummy frame
> > or asigning the current frame to last*
> I took the easy way ;)
> 
> Patch attach.

easy is good and applied

[...]


-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Let us carefully observe those good qualities wherein our enemies excel us
and endeavor to excel them, by avoiding what is faulty, and imitating what
is excellent in them. -- Plutarch
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