working direct mplayer on cx88 analog video (was: Re: cx88 panic, and a (hacky) way to grab composite/svideo in when it's not panicing :) (and vlc...) (Juergen Lock))

Juergen Lock nox at
Thu May 28 17:02:58 UTC 2009

On Wed, May 27, 2009 at 05:19:08PM -0500, Jason Harmening wrote:
> On Wed, May 27, 2009 at 4:34 PM, Juergen Lock <nox at> wrote:
> > In article <2d1264630905270827q4e85376ds530488edf62b4c1a at> you write:
> >>
> > Actually my vlc invocation,
> >
> >>>        vlc --demux rawvideo --rawvid-fps 25 --rawvid-width 768 --rawvid-height 576 --rawvid-chroma I422 vpipe
> >
> > uses the raw video from the vpipe directly so there's no mpeg involved.
> > (But still the video is jerky.)
> >
> >>> (I first wanted to do this with mplayer but the closest I got,
> >>>        mplayer -demuxer rawvideo -rawvideo w=768:h=576:format=422p:size=884736 vpipe
> >>> still gets false colours.)
> >>>
> >  And btw doing it with mplayer like this doesn't seem to be affected by
> > the jerkyness, only the colours are wrong.  (Maybe there's a way to do it
> > right with a more recent mplayer, but unfortunately there's no mplayer
> > svn snapshot in ports and they stopped doing formal releases so our
> > mplayer is now pretty old... ):
> >
> >  So maybe the above is just a bug in vlc?  (And also, mplayer only uses
> > ~8% cpu for this here while vlc uses around 20%...)
> It does seem likely that it's a VLC bug then.  How exactly are the
> colors wrong in mplayer?

Hmm difficult to explain...  red becomes blue, etc.

>  The cx88 app captures in YUV422 planar IIRC,
> but the kernel drivers allow selection of different pixel formats.
> Perhaps a more straightforward RGB format would work better.  You'd
> have to hack the cx88 app to do that right now, since I don't (yet)
> have a command-line option for it.
 Anyway, with the help of the nice people on #mplayer (thanx! :) I now
have a working mplayer commandline:
	mplayer -demuxer rawvideo -rawvideo w=768:h=576:format=422p:size=884736 -vf swapuv,scale=-1:-1 vpipe
(vpipe still being the named pipe fed by something like
	cx88 -d /dev/cx88video0 -u file://${PWD}/vpipe -x cx88.xml -c ...

 So it looks like for some reason mplayer's format=422p takes u and v
swapped...  (The good news is the filter doesn't seem to noticeably
increase the cpu load at least here so its still way better than vlc.)


> >  Will this also include the dvb-s(2) code that was mentioned on
> > this list once (I think by Konstantin)?
> I know Konstantin has at least some of it working, but you'd have to
> ask him to be sure.  There will need to be a cx88 update to add
> support for additional DVB-S(2) tuning params to the XML file, but
> most of the work will actually have to be done in libtuner.  I may end
> up pushing the big cx23885 update first just to get some breathing
> room.

 Ok.  Thanx again,

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