[Ffmpeg-devel] MpegEncContext Pictures in codec development

[Michael Niedermayer]

Hi

On Fri, Sep 29, 2006 at 09:15:06PM +0200, Denis Fortin wrote:
> Le vendredi 29 septembre 2006 ? 20:59 +0200, Michael Niedermayer a
> ?crit :
> > Hi
> > 
> > On Thu, Sep 28, 2006 at 09:37:30PM +0200, Denis Fortin wrote:
> > > Hi,
> > > 
> > > I'm writing a codec (vc1 coder), and i'm a little confused about all
> > > those pictures in 
> > > MpegEncContext.
> > > 
> > > Currently i need to store the result of an encoded/decoded I frame (for
> > > future use in P frames). From what i could understand new_picture is the
> > > original picture (the one to encode) and current_picture is the one i
> > > should use to store the encoded/decoded I frame.
> > > Am i right ?
> > 
> > yes
> > 
> > 
> > > Then how can i get a correctly allocated current_picture ?
> > 
> > IIRC MPV_frame_start() does that for you
> > 
> > 
> > > 
> > > More generally, how the picture/ff_find_unused_picture stuff is
> > > working : 
> > 
> > RTFS :)
> > but maybe you wont need ff_find_unused_picture() at all i dunno
> > 
> > 
> > > When encoding a P frame, how should i get the forward/backward ref
> > > pictures ?
> > 
> > P frames dont have backward ref pictures
> > 
> > 
> > > How the reordered P frames are stored while encoding the forward ref
> > > picture ?
> > >            vv        
> > >           IPPIPP...
> > 
> > if you have only I and P frames then there should be no reordering
> 
> Thanks for your answers.
> I started this encoder without using much of mpegvideo.c but
> after more RTFS i think it's more reasonable to integrate it in
> mpegvideo.c like the wmv2 encoder and use some new switch()  
> 	case CODEC_ID_WMV3:
>           case CODEC_ID_VC1: 
>  	...
> 
> is this kind of patch acceptable ?

probably

[...]
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

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