[Ffmpeg-cvslog] CVS: ffmpeg/libavcodec mpegvideo.c, 1.503, 1.504 mpegvideo.h, 1.234, 1.235 h263.c, 1.298, 1.299

[Guillaume POIRIER]

Hi,
On 2/3/06, Corey Hickey <bugfood-ml at fatooh.org> wrote:

[..]


> vmax_b_frames=3:vb_strategy=2
>   pass 1:
> PSNR: Y:41.45, Cb:44.92, Cr:45.40, All:42.37
> user    729m40.550s
>   pass 2:
> PSNR: Y:42.25, Cb:45.24, Cr:45.99, All:43.11
> user    188m33.290s
> frame counts: I:   3424  1%  P:  65680 33%  B: 126962 64%
> average qps:  I: 2.607185    P: 3.043849    B: 5.030922
>
> This one takes the crown PSNR-wise, with a +0.07 dB increase over using
> turbo. Compared to vmax_b_frames=2:vb_strategy=2:brd_scale=0 (without
> turbo), though, it doesn't really look better. Some parts looked a bit
> better and some looked worse, but, on average they both looked about the
> same.

Ok, this looks like turbo would benefit from a slight lifting.
Currently, turbo pretty much disables all encoding options but keeps
the given max number of bframes unchanged.

I'd like to have 2 modes for turbo, just like x264:
turbo=1 for a speed-up without any noticeable change in quality
turbo=2 for the greatest quality with some decrease in quality, which
would be current turbo mode.

However, I don't know what options are supposed to have the most
influence on getting the best first pass stats.
I guess leaving in trellis and mbd=2 should make the encode be closer
to how the encode would look like without turbo mode... therefore it
should produce better stats. But are there any other particular option
that really shouldn't be left out?

Guillaume
--
A word to the wise ain't necessary - it's the stupid ones that need the advice.
    Bill Cosby

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