[MPlayer-dev-eng] [PATCH] libavcodec skip decoding options

[Zoltan Hidvegi]

Jan Knutar wrote:
[ Charset ISO-8859-1 unsupported, converting... ]
> On Friday 15 July 2005 13:00, Reimar Döffinger wrote:
> 
> > skiploopfilter can give a big speedup with h264 at little cost.
> 
> I didn't get much speedup while testing x264 generated stuff. Do I have
> to turn on some special option in x264, or use some special bitrate to
> cause files which speed up alot with skiploopfilter?

On a Thinkpad X22 with 533MHz PIII (800MHz speedstepped down) I get
17% speedup with skiploopfilter=bidir and 37% speedup (i.e. 100fps
without, 137 fps with) with skiploopfilter=nonkey on an x264 generated
720x400 video with a bit more than 50% of the frames are b-frames.
Not nearly 2x, but significant.  The speedup is only in the codec
part, once you add vo, ao, ad etc. it's much less, but it can still
make a big difference on a video which almost works without it.  Even
though it is a quite high quality encoding, I notice lots of visible
artifacts with skiploopfilter=nonkey.  I see no artifacts with
skiploopfilter=bidir, even though I've used b_pyramid.  The lower
quality video you have, the more artifacts you will see with
skiploopfilter=nonkey.  The amount of filtering is determined during
encoding, if you encode the video with nodeblock, skiploopfilter will
not do anything.  Also very high quality encodes do not use deblocking
(I guess qp_constant <= 18 or something like that).

Zoli