[FFmpeg-devel] [PATCH 2/2] lavc/vvc: Fix pps_single_slice_picture

[Nuo Mi]

On Tue, Feb 25, 2025 at 3:16 AM Frank Plowman <post at frankplowman.com> wrote:

> On 24/02/2025 02:23, James Almer wrote:
> > On 2/23/2025 9:04 AM, Frank Plowman wrote:
> >> Signed-off-by: Frank Plowman <post at frankplowman.com>
> >> ---
> >>   libavcodec/vvc/ps.c | 3 ++-
> >>   1 file changed, 2 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/libavcodec/vvc/ps.c b/libavcodec/vvc/ps.c
> >> index fae6655cc0..603a6d42d1 100644
> >> --- a/libavcodec/vvc/ps.c
> >> +++ b/libavcodec/vvc/ps.c
> >> @@ -368,9 +368,10 @@ static int pps_add_ctus(VVCPPS *pps, int *off,
> const int rx, const int ry,
> >>
> >>   static void pps_single_slice_picture(VVCPPS *pps, int *off)
> >>   {
> >> +    pps->num_ctus_in_slice[0] = 0;
> >>       for (int j = 0; j < pps->r->num_tile_rows; j++) {
> >>           for (int i = 0; i < pps->r->num_tile_columns; i++) {
> >> -            pps->num_ctus_in_slice[0] = pps_add_ctus(pps, off,
> >> +            pps->num_ctus_in_slice[0] += pps_add_ctus(pps, off,
> >>                   pps->col_bd[i], pps->row_bd[j],
> >>                   pps->r->col_width_val[i], pps->r->row_height_val[j]);
> >>           }
> >
> > Is there a sample in the conformance suite this fixes? Or one we can
> > upload to FATE to make a test.
>
> Hi James,
>
> The conformance suite is pretty lacking here considering the number of
> combinations of these different partitioning tools possible in VVC.
> I think the lack of examples in the conformance suite is the main reason
> we're still running into bugs in this area.
>
> I crafted a sample which exhibits this bug though, and have sent it to
> samples-request at ffmpeg.org.  I tried to also craft a sample which tests
> 93aae172ea909ec96b67077b8b3005886a83d0ae, but any attempt at this seemed
> to segfault the reference software :)
>
Creating error-prone conformance streams is challenging; some companies
sell them at a high price

>
> --
> All the best,
> Frank
>
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