[MEncoder-users] Encodes for slow laptop

Stella-Terra Clemens stellaterraclemens at gmail.com
Wed Jun 11 19:24:27 CEST 2008


On Wed, Jun 11, 2008 at 9:41 AM, Diogo Franco <diogomfranco at gmail.com>
wrote:

> Em Qua, 2008-06-11 às 09:16 -0700, Stella-Terra Clemens escreveu:
> > resolutions, in 5 different bitrates.  Then, I'm going to create another
> > shell script (though I'm having a little trouble with this) that will run
> > each file in mplayer using the -vo null -nosound -noskip -benchmark and
> > parsing out the results in second and storing them in a CSV file which I
> can
> > then import into a spreadsheat and graph.
> There will be no speed difference between libavcodec and xvid, except
> for quality and ENCODING time because they're two different encoders for
> the same specification. Only libavcodec is used for decoding by mplayer
> and xvid doesn't implement a decoder so the difference between them is
> IMO not worth testing.
>
> You should also pick up a video that works and test some 'vo's and see
> which one is the fastest. You can do it with '-hardframedrop -benchmark'
> and see on the status line which one drops less frames, or just the one
> that uses less cpu time. Remember to use '-lavdopts skiploopfilter=all'
> to decode the h.264 videos, it will gain a lot of speed.
>
> Some VOs to try:
> xv
> gl
> gl:force-pbo
> gl2
> gl2:noglfinish
>
> Before trying the gl 'vo's, check the output of "glxinfo | grep 'direct
> rendering'". If it says "No", then install accelerated drivers for you
> video card. If there aren't any, then don't bother testing them.
> 
> For xv, take a look at the output of "xvinfo | grep Adaptor" and test
> each line on the vo. For example, with my NV18, that command outputs:
>  Adaptor #0: "NV17 Video Texture"
>  Adaptor #1: "NV05 Video Blitter"
>
> Then you use '-vo xv:adaptor=NUMBER' and see which one is the fastest.
> In my case, 'xv:adaptor=1' is faster than the default 'adaptor=0'. Also,
> for me 'gl2:noglfinish' is the only one faster than 'xv:adaptor=1'.
>
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>

Yeah, unfortunately, though the drivers are TECHNICALLY accelerated, it's an
onboard video card and I get 60 FPS from glxgears.  I can try the different
VOs later, but I'm fairly confident anything GL related is going to go up in
smoke.
I'll check out the stuff with the adapters, but, again, support for this
video card isn't that great, so I have low confidence of improvement.
I have "-lavdopts skiploopfilter=all" in my .mplayer/config file.
As for libavcodec and xvid being the same: that puzzles me.  So, as I
understand it, they're both just different applications that encode video
into MPEG-4 Part 2, wheras x.264 encodes into MPEG-4 part 10.  In which
case, why were people earlier saying there would be a difference in the
speed of decoding libavcodec encoded files?  Also, are there any other
encodings (aside from MPEG-4 Parts 2 and 10) that I should try?  Obviously
there's MPEG-1 and MPEG-2, but those are the only 4 encodings I know of.
Thank you,
Stella


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