[Mplayer-cvslog] CVS: main/libmpcodecs vd_ffmpeg.c,1.108,1.109

Roberto Togni r_togni at tiscali.it
Mon Nov 10 22:53:22 CET 2003

On 2003.11.10 01:52, Michael Niedermayer wrote:
> Hi
> On Monday 10 November 2003 00:56, Roberto Togni CVS wrote:
> [...]
> this will break if IP(B) style codecs set buffer_hints, which they
> dont
> currently, but they should
My point in this patch was to enable codecs i'm moving to ffmpeg to get  
the correct buffer type, while taking all efforts not to break anything  
for existing codecs. That's why i coded the patch in this way, so that  
codecs that do not set buffer hints have their buffer allocated in the  
old way.
I can modify some other codecs (like huffyuv or mjpeg) to take  
advantage of the new scheme, but i don't know how to handle IP(B)  
codecs. I assume that the person that will modify IPB codecs to use  
buffer hints will also take care of updating vd_ffmpeg.
I can do it, but someone have to tell me how to do it. Is it enough to  
set preserve and readable for I and P frames (so they get a static  
buffer) and nothing for B frames (to get a non readable temp buffer)?  
That sounds logic, but does not mimic the current behaviour. Or do we  
need some other kind of hints to allocate a MP_IMGTYPE_IPB buffer?

> btw, i would prefer if we would add a reget_buffer() function instead
> of
> missuseing get_buffer() for CR buffers
Ok for me. But we have to set for a solution ASAP, because the number  
of codecs that have to be modified and tested with every change is  

> the default reget_buffer() could simply reuse the buffer if its
> FF_BUFFER_TYPE_INTERNAL and call get_buffer(), memcpy(),
> release_buffer() if
> that would also avoid the cr_available negotiation and emulation in
> every
> codec if cr_available == 0
That's sub-optimal when the codec can easily know which portions of the  
picture didn't change, but surely it's simpler that the current  

Anybody against it? Should i implement it or do we have to discuss it  
on ffmpeg-dev?

> Michael

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