[Ffmpeg-devel] Accepted SoC Apps

Loren Merritt lorenm
Fri May 26 00:02:27 CEST 2006

On Thu, 25 May 2006, Michael Niedermayer wrote:

> things to do for snow:
> * multiple reference frames support
>  +number of picture buffers field per keyframe
>  +decode frame buffer index (into which decoding happens)
>  +display frame buffer index (which frame is outputed)
>  +a symbol per block to select the reference frame
>  +some changes to the motion estimation code
>  +some changes to the mv prediction code

I have a patch for multiref support. Will post once it's cleaned up.
Preliminary results: at high bitrates, it helps just as much as h264's 
multiref. At low bitrates, not as much. This might be because I have not 
yet modified mv prediction.

> * non translational motion compensation
>  +estimate non translational parameters per block by using surrounding
>   motion vectors
>  +add a ac coded bit per block to switch between translational and non
>   translational MC
>  +borrow the non translational MC code from libmpcodecs/vf_perspective.c
>  +some changes to the encoder to decide between translational and non t.
> * trellis quantization (select quantized coefficient so as to minimize
>   the ratedistrortion
> * 4x4 sized block support (we have 16x16 and 8x8 currently)
> * 1/8 pel motion compensation / estimation support (pretty much just
>  encoder changes needed which in case of the iterative me should be
>  trivial)
> * 1 pass ratecontrol

* Figure out how to optimally use intra. There are cases where enabling 
8x8 blocks greatly reduces quality per bitrate, and I think this is mostly 
due to trying to encode in intra prediction what could be left to the wavelet.

--Loren Merritt

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