[XviD-devel] I haven't been here for 4 days and what I see? :)

[peter ross]

hi,

>1. I had some fun testing a different approach for adding motion vector
>lenght to SAD in motion search. My reasoning was as follows: "if you
>can find a good match, go for it (-> don't take d_mv_bits too
>seriusly); if you cannot find a good match, then at least try to limit
>number of bits for a motion vector (-> d_mv_bits more important)".
>This may sound strange, but believe me, I used to test more crazy
>ideas ;)
>Anyway, my tests show that I can get about 0.15 .. 0.20 dB PSNR
>improvement for free. Nice isn't it?
>The only probem I'm currently having is inter4v search/decision - it
>just doesn't work (total gain from inter4v below 0.05dB) and I have to
>work a bit more on this.

how many different sources have you tried it with?

>2. Using chroma information for motion search. Everyone knows that
>using chroma planes for motion search is slow, pointless an not worth
>the effort. However, I wounldn't be me if I didn't check it myself,
>right?
>So I added chroma SAD to ME. The results are:
>  - encoding is 5..7 % slower
>  - PSNR gain for normal movies is 0.05.. 0.10 dB
>  - PSNR gain for animation and computer graphics (tested on Warcraft III
>  trailer) is 0.20dB and higher in high-motion&lots of colours.
>  - "visual quality" seems to be better - there is no big and ugly
>  colour blocks in the video (especially fast and colourful video)
>
>It's possible that chroma info can help in noisy videos, and it may
>also help with b-frames (simply because victors are closer to 'real'
>motion).
>The code is quite short and simple, it also works with qpel.
>What do you think? Should I add a motion flag and implement it?

sounds exceptionally good. commit.
(and gruel, this might another xvid "first"; first ever mpeg-4 codec
to consider chroma data)

-- pete

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