[FFmpeg-devel] [PATCH] h264 bitstream filter

[Michael Niedermayer]

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:
> >>>>     
> >>>>         
> >>>>> Hi
> >>>>>
> >>>>> On Tue, Sep 04, 2007 at 09:10:43AM +0200, Benoit Fouet wrote:
> >>>>>   
> >>>>>       
> >>>>>           
> >>>>>> Loren Merritt wrote:
> >>>>>>     
> >>>>>>         
> >>>>>>             
> >>>>>>> On Mon, 3 Sep 2007, Trent Piepho wrote:
> >>>>>>>
> >>>>>>>   
> >>>>>>>       
> >>>>>>>           
> >>>>>>>               
> >>>>>>>> In the standard, it says stuff like:
> >>>>>>>>
> >>>>>>>> "Annex B \n Byte stream format"
> >>>>>>>> "B.1 Byte stream NAL unit syntax and semantics"
> >>>>>>>> "B.2 Byte stream NAL unit decoding process"
> >>>>>>>>
> >>>>>>>> That phase "Byte stream NAL unit" is used over and over.  So maybe
> >>>>>>>> something like bsnal or bsNAL?
> >>>>>>>>     
> >>>>>>>>         
> >>>>>>>>             
> >>>>>>>>                 
> >>>>>>> "Byte stream NAL unit" is a specific piece of the format. "Annex B byte 
> >>>>>>> stream" is the name of the format as a whole, which I would abbreviate 
> >>>>>>> "Annex B".
> >>>>>>>
> >>>>>>>   
> >>>>>>>       
> >>>>>>>           
> >>>>>>>               
> >>>>>> updated patch attached, which also takes advantage of the brand new
> >>>>>> close filter function :)
> >>>>>>     
> >>>>>>         
> >>>>>>             
> >>>>> 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

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Those who are too smart to engage in politics are punished by being
governed by those who are dumber. -- Plato 
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