[Ffmpeg-devel] Re: [RFC] mpeg2 422 encoding.

[Michael Niedermayer]

Hi

On Sun, May 07, 2006 at 08:12:58PM +0200, Baptiste COUDURIER wrote:
> Hi
> 
> Michael Niedermayer wrote:
> > [...]
> > 
> > no, there are no motion vectors for chroma the chroma vectors are the same
> > as the luma vactors (ignoring scaling & rounding ...)
> > 
> > and i dont think that theres a relation between -me xyz, the number of b
> > frames and the (-mbd bits) bug its probably just a "coincidence"
> > you should rather look at the mb_decision != 0 specific code, i also
> > think that the mbd bits bug isnt critical and could be dealt with after
> > 422 encoding support has been added
> > 
> 
> All right then,
> 
> A new patch is attached I only inlined encode_mb, and mpeg1_encode_mb in
> mpeg12.c, I left START/STOP TIMER funcs around encode_picture.
> Interlaced encoding in 422 works. I removed all encode_mb_hq changes for
> now.
> 
> I get good performance with that patch. Equal/faster on xeon 2.8ghz. I
> wonder why faster sometimes, maybe inlining whole encode_mb did that.
> What do you get ?

faster too (amd duron 800mhz), no clue why either ...

patch ok, a few minor cosmetical ideas below though (can be ignored or
commited later)


[...]
> +        switch (s->chroma_format){
> +        case CHROMA_422:
> +            avctx->profile = 0;
> +            break;
> +        case CHROMA_420:
> +        default:
> +            avctx->profile = 4;
> +            break;
> +        }

if(s->chroma_format == CHROMA_422)
    avctx->profile = 0;
else
    avctx->profile = 4;

is half the number of lines ...

    chroma_format2profile[4]={4,4,0,4};
    avctx->profile= chroma_format2profile[s->chroma_format]

is a quarter though maybe less readable


[...]
> +                if (s->chroma_format == CHROMA_420)
> +                    put_bits(&s->pb, 1, 0); //escx
> +                else
> +                    put_bits(&s->pb, 1, 1); //escx

put_bits1(&s->pb, s->chroma_format != CHROMA_420); //escx


[...]

-- 
Michael

In the past you could go to a library and read, borrow or copy any book
Today you'd get arrested for mere telling someone where the library is