[MPlayer-users] Problem using vb_strategy=1

[Stefan Baehre]

D Richard Felker III wrote:

> If this "bug" exists, it makes sense that quality always improves.
> Using more than one B frame always reduces quality.

It doesn't always improve. My best encodings so far are with 2
b-frames and vb_strategy=0.

I have some numbers for an encoding of "Lord of the Rings 1 SE DVD"
at hand. I made a statistic of the frequency of the PSNRs for a high
quality encoding with Q=2 and different numbers of b-frames.

http://www.ixtools.de/video/lotr1.pdf

The worst encoding is without b-frames. 1 b-frame improves the
situation, but vb_strategy=1 decreases it here. The optimum is with 2
b-frames and vb_strategy=0, again vb_strategy=1 decreases quality a
little bit. 3 b-brames is nearly the same as 2 b-frames when using
vb_strategy=1. The encoding with 3 b-frames and vb_strategy=0 is
still running.

I did the same for "The Ring DVD" and get comparable results. The
optimum was at 2 b-frames with vb_strategy=0 too. But 1 b-frame and
vb_strategy=1 was nearly as good in that case and far better than 1
b-frame with vb_strategy=0.

(I worked around my b-frames problem here. So 1 b-frame with
vb_strategy=1 means "vmax_b_frames=2:vb_strategy=1").