[MPlayer-users] mplayer and theora?

[Jeff Clagg]

On Fri, Feb 24, 2006 at 06:24:04PM -0500, Bradley Alexander wrote:

> mencoder ${infile} -o /dev/null -oac copy -ovc lavc -lavcopts
> vcodec=mpeg4:vbitrate=
> ${bitrate}:vhq:vqmin=2:vlelim=-4:vcelim=9:lumi_mask=0.05:dark_mask=0.01:vpass=1 -vf scale=640:480 -sws 2 -vop pp=fd
> 
> I include these because I have been using these scripts for a couple of
> years and options have changed and so forth, so I'm basically doing a
> peer review.

OK, here's what's "new." vhq is not recommended. Roughly, use mbd=0 if
you like fast, and mbd=2 for high quality. vqmin=2 is the default, and
I'm pretty sure it always was, so not sure why it's even in there. I
find lumi/dark masking dubious (especially dark_mask), but perhaps this
is taste, and may depend on the screen. For more quick ideas, see
http://mplayerhq.hu/DOCS/HTML/en/menc-feat-enc-libavcodec.html#menc-feat-dvd-mpeg4-lavc-encoding-options

Also, -vf and -vop are for the same purpose, only -vop has really
annoying syntax and so is deprecated. A more modern approach would be "-vf
pp=fd,scale=640:480".  (I'm curious where you got that command line from.)

> I also have a Sharp Zaurus, which runs MPlayer 1.0pre7. Being space
> constrained, I have been working to convert some videos to ogg theora
> for playback on the Zaurus. The script I wrote for it strips the sound
> to a wav, downsamples to 24000Hz and resizes the video to 320x240 with
> no sound, converts the wav to ogg and recombines them. It seems to work
> with .wmvs I download from the internet, but not with avi format --
> either ones I recorded from the tv capture card or downloads from the
> Internet.

This'll probably sound pedantic, and it doesn't directly answer anything
you asked, but here goes. Ogg is a (dumb) container format. Vorbis is
the name of the (genuinely quite good) audio codec that is incestuously
linked with Ogg. Mplayer 1.0pre7 doesn't believe in vorbis-in-avi, but
I believe there is a particular way of doing this in more recent
mplayers; if my belief is right, though, you can't expect any other
player to ever play it IMO. Most people will probably just tell you that
vorbis-in-avi is impossible. It may be possible, but this doesn't
necessarily mean it's a good idea...

I don't know why Theora is in the subject line, but if you really care
about space efficiency, you're way better off sticking with lavc's
mpeg4. Theora is the name of a video codec from the Xiph people, and is
in turn very close to On2's VP3. A few people people believe that Theora
is hugely overhyped. In any case it's probably not worth looking into
for what you're doing.

Hope this answered at least a few of your questions. I know I answered
some you didn't ask. Sorry.