[FFmpeg-devel] [PATCH] h264 bitstream filter

Benoit Fouet benoit.fouet
Tue Sep 4 16:29:24 CEST 2007


Benoit Fouet wrote:
> Michael Niedermayer wrote:
>   
>> Hi
>>
>> On Tue, Sep 04, 2007 at 02:50:38PM +0200, Benoit Fouet wrote:
>>   
>>     
>>> Michael Niedermayer wrote:
>>>     
>>>       
>>>> Hi
>>>>
>>>> On Tue, Sep 04, 2007 at 02:40:50PM +0200, Benoit Fouet wrote:
>>>>   
>>>>       
>>>>         
>>>>> Michael Niedermayer wrote:
>>>>>     
>>>>>         
>>>>>           
>>>>>> Hi
>>>>>>
>>>>>> On Tue, Sep 04, 2007 at 02:35:01PM +0200, Benoit Fouet wrote:
>>>>>>   
>>>>>>       
>>>>>>           
>>>>>>             
>>>>>>> Michael Niedermayer wrote:
>>>>>>>     
>>>>>>>         
>>>>>>>             
>>>>>>>               
>>>>>>>> doesnt the code miss reformating slices and other multiple nal units
>>>>>>>> per frame?
>>>>>>>>
>>>>>>>>   
>>>>>>>>       
>>>>>>>>           
>>>>>>>>               
>>>>>>>>                 
>>>>>>> i was thinking that the filter received nal units, not frames.
>>>>>>> am i wrong ?
>>>>>>>     
>>>>>>>         
>>>>>>>             
>>>>>>>               
>>>>>> it should receive frames but it would be best if it would work with
>>>>>> both frames as well as nal units ...
>>>>>>
>>>>>>   
>>>>>>       
>>>>>>           
>>>>>>             
>>>>> that means input has to be parsed, or ?
>>>>> is there such a parser ?
>>>>>     
>>>>>         
>>>>>           
>>>> ?
>>>>
>>>> if you get nal units you output nal units
>>>> if you get frames you output frames
>>>> just change the headers from len to 001
>>>>
>>>>   
>>>>       
>>>>         
>>> this means reallocating in case len is not coded on 4 bytes
>>>     
>>>       
>> you dont need 4 bytes
>> 3 bytes ( 00 00 01 ) is enough, the 4th 00 is only needed before
>> SPS, PPS and the first NAL unit of an access unit
>>
>>   
>>     
>
> ok, then, how is the attached patch ?
> (i also added a check on length size)
>
>   

ahem... sorry, updated patch attached, the previous one was writing
headers at the wrong place for nal units which were not the first one of
the access unit

the fact is i hadn't tested with frames containing multiple nal units,
if someone has such a file and can share it, i'd be grateful.

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