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

[Frank Plowman]

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 :)

--
All the best,
Frank