[FFmpeg-devel] [PATCH 1/2] avcodec/vvc/refs: fix negative pps_scaling_win offsets

[Michael Niedermayer]

On Mon, Feb 03, 2025 at 08:05:19AM +0000, Frank Plowman wrote:
> On 02/02/2025 21:17, Michael Niedermayer wrote:
> > The spec seems to allow these to  be negative
> > 
> > Fixes: left shift of negative value -15
> > Fixes: 392687035/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VVC_fuzzer-6559804532785152
> > 
> > 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/vvc/refs.c | 8 ++++----
> >  1 file changed, 4 insertions(+), 4 deletions(-)
> > 
> > diff --git a/libavcodec/vvc/refs.c b/libavcodec/vvc/refs.c
> > index 8d4b7bb35b2..486515d06db 100644
> > --- a/libavcodec/vvc/refs.c
> > +++ b/libavcodec/vvc/refs.c
> > @@ -147,10 +147,10 @@ static VVCFrame *alloc_frame(VVCContext *s, VVCFrameContext *fc)
> >          for (int j = 0; j < frame->ctb_count; j++)
> >              frame->rpl_tab[j] = frame->rpl;
> >  
> > -        win->left_offset   = pps->r->pps_scaling_win_left_offset   << sps->hshift[CHROMA];
> > -        win->right_offset  = pps->r->pps_scaling_win_right_offset  << sps->hshift[CHROMA];
> > -        win->top_offset    = pps->r->pps_scaling_win_top_offset    << sps->vshift[CHROMA];
> > -        win->bottom_offset = pps->r->pps_scaling_win_bottom_offset << sps->vshift[CHROMA];
> > +        win->left_offset   = pps->r->pps_scaling_win_left_offset   * (1 << sps->hshift[CHROMA]);
> > +        win->right_offset  = pps->r->pps_scaling_win_right_offset  * (1 << sps->hshift[CHROMA]);
> > +        win->top_offset    = pps->r->pps_scaling_win_top_offset    * (1 << sps->vshift[CHROMA]);
> > +        win->bottom_offset = pps->r->pps_scaling_win_bottom_offset * (1 << sps->vshift[CHROMA]);
> >          frame->ref_width   = pps->r->pps_pic_width_in_luma_samples  - win->left_offset   - win->right_offset;
> >          frame->ref_height  = pps->r->pps_pic_height_in_luma_samples - win->bottom_offset - win->top_offset;
> >  
> 
> This patch LGTM.

will apply

thx

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

During times of universal deceit, telling the truth becomes a
revolutionary act. -- George Orwell
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