[FFmpeg-devel] [PATCH] H264. Check if more RBSP data in PPS provided by current profile due to Annex A.

[Anatoly Nenashev]

On 25.11.2011 18:44, Michael Niedermayer wrote:
> On Fri, Nov 25, 2011 at 05:49:44PM +0400, Anatoly Nenashev wrote:
>    
>> Subj.
>>
>> This patch also fix issue https://ffmpeg.org/trac/ffmpeg/ticket/685.
>>
>>      
>    
>>   h264_ps.c |   19 ++++++++++++++++++-
>>   1 file changed, 18 insertions(+), 1 deletion(-)
>> 705fb675467c14ef8f7ee9777a8cb3f324254bdb  h264_profile_check.patch
>> diff --git a/libavcodec/h264_ps.c b/libavcodec/h264_ps.c
>> index 7a4cfb0..111a6a3 100644
>> --- a/libavcodec/h264_ps.c
>> +++ b/libavcodec/h264_ps.c
>> @@ -485,6 +485,23 @@ build_qp_table(PPS *pps, int t, int index, const int depth)
>>           pps->chroma_qp_table[t][i] = ff_h264_chroma_qp[depth-8][av_clip(i + index, 0, max_qp)];
>>   }
>>
>> +static int more_rbsp_data_in_pps(H264Context *h)
>> +{
>> +    const SPS *sps =&h->sps;
>>      
> this could be wrong if there are multiple sps, it should use
> h->sps_buffers[pps->sps_id]
>
>
>    

Ok.

>> +    const int profile_idc = sps->profile_idc;
>> +    const int constraint_set_flags = sps->constraint_set_flags;
>> +
>> +    if (profile_idc == 66 || profile_idc == 77 ||
>> +        profile_idc == 88 || constraint_set_flags&  7)
>>      
> maybe a more minimal check would be safer, that is incase some other
> encoder sets the profile wrong
>
>
>    

There is a note in specification, section 7.4.2.1.1:

"NOTE 1 – When one or more than one of constraint_set0_flag, 
constraint_set1_flag, or constraint_set2_flag are equal to 1, the
coded video sequence must obey the constraints of all of the indicated 
subclauses of subclause A.2. When profile_idc is equal to
44, 100, 110, 122, or 244, the values of constraint_set0_flag, 
constraint_set1_flag, and constraint_set2_flag must all be equal
to 0."

Thus we may just check that constraint_set_flags & 7 is not 0. See new 
patch in attachment.

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