[FFmpeg-devel] [PATCH] h264 bitstream filter

Benoit Fouet benoit.fouet
Fri Aug 31 12:31:59 CEST 2007


Benoit Fouet wrote:
> Benoit Fouet wrote:
>   
>> M?ns Rullg?rd wrote:
>>   
>>     
>>> This is wrong.  Maybe you misunderstood what I said about where to
>>> insert SPS and PPS.
>>>     
>>>       
>> it seems so...
>>
>>   
>>     
>>>   They should be added before the first type 5 NAL
>>> unit of an IDR picture, after whatever SEI or AUD units that picture
>>> has.  A multislice IDR picture only needs SPS and PPS before the first
>>> slice, and non-IDR pictures should not have SPS or PPS added.
>>>
>>>   
>>>     
>>>       
>> i'm not sure i get it, here is what i understood, please correct me if
>> i'm wrong
>> i receive NALU in the filter
>> if it's the first coded slice of an IDR picture (type 5 NAL), i prepend
>> sps and pps NALUs (i don't really have to care about SEI or AUD in the
>> bitstream filter case, right?)
>> else, i don't add sps and pps
>>
>> this would give, in pseudo code:
>>
>> if (not sps and pps data)
>>   retrieve sps and pps
>>   first_idr=1
>>
>> if (first_idr && nal_unit_type == 5)
>>   prepend sps and pps
>>   first_idr=0
>> else
>>   don't prepend sps and pps
>>   if( nal_unit_type != 5)
>>   
>>     
>
> when i think about it, i'd put:
> if (nal_unit_type == 1) instead...
>
>   
>>     first_idr=1
>>
>> is this right ?
>>     

updated patch attached, which should address all problems (apart from
the above one, if i misunderstood once again, and the naming)

-- 
Ben
Purple Labs S.A.
www.purplelabs.com
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