xv overlay - cinema mode

Alex Deucher alexdeucher at gmail.com
Thu Mar 22 13:12:15 PDT 2007

On 3/22/07, Wesley S. <profox at ubuntu-nl.org> wrote:
> 2007/3/22, Dirk Thierbach <dthierbach at gmx.de>:
> > On Thu, Mar 22, 2007 at 05:41:33PM +0100, Wesley S. wrote:
> > > 2007/3/22, Alex Deucher <alexdeucher at gmail.com>:
> > > >On 3/22/07, Wesley S. <profox at ubuntu-nl.org> wrote:
> >
> > >>> Is it possible to use xv overlay to play a movie fullscreen on my
> > >>> TV, but windowed on my computer? (or even minimized on my
> > >>> computer)
> >
> > >> Just set up dualhead and play the video on one head while you work on
> > >> the other.  That's all the "cinema" mode does I suspect.
> >
> > > Thanks for your answer, Alex. But unfortunately this is not what I
> > > am looking for.  It's a workaround, but not a real solution for me.
> >
> > Why is it a workaround? As long as you get the movie fullscreen on
> > the TV, and windowed on your computer as you wanted, it shouldn't matter
> > how the hardware does it.
> Well, if I set up dualhead and play the video on one head (TV) and do
> other things on the other head (computer) I won't see the video
> windowed on my computer, or am I missing something here
> > > I am pretty sure that I won't have much chance of finding this functionality
> > > in linux, because I have already looked everywhere, and I found it nowhere.
> > > So this is sort of my last try. But hey, if it doesn't work, I'll just keep
> > > using the dualhead option. It's not as nice as theatre mode, but it's
> > > workable..
> >
> > Why is it not as nice? There should be no difference. Or is the problem
> > that the screen size on your TV is not as you would like it?
> Same reason as above. I won't see the video windowed on my computer,
> only fullscreen on TV, atleast that's what I thought.
> > > All this stuff brings me to a new question though. How hard would it be to
> > > do this through software? Wouldn't the computer be able to copy the contents
> > > of a playing video on screen 1 to screen 2?
> >
> > I'd say that's exactly what the computer does, no matter if you call it
> > "Theatre Mode", "Cinema Mode", or "Video Mirroring" :-)
> I agree that the naming doesn't matter ;) but I just don't understand
> how I can make the software copy the contents of a playing video on
> screen 1 (computer) to screen 2 (TV) You make it sound like it's
> nothing... Am I missing something?
> Thanks for your answer though.
> 2007/3/22, Alex Deucher <alexdeucher at gmail.com>:
> > CRTCs are the part of the video chip that controls the timing and part
> > of the frambuffer that gets sent to an output.
> > [ ... ]
> Thanks for the explanation, Alex!
> > Since hardware usually only has one overlay, you could only
> > do HW scaling and colorspace conversion on one output.  So:
> > 1. set up dualhead (with or without xinerama)
> > 2. hack you video app to output to two buffers (one on :0.0 and one on
> > :0.1 if no xinerama)
> It sounds very interesting and I'd like to try it out, but I have no
> idea how I would do this. Sure, I have programmed before, but this is
> something completely different. If you can point me to documentation I
> might need to hack the video app (mplayer in my case) I'd be very
> happy... I will try to do something.. eventhough I have never messed
> around with video output drivers before. I'm not even sure where to
> start. Would I try to hack the video output driver I am using (xv in
> my case) ? I'm afraid that this is a bit over my head.

I'm not really familiar with the mplayer code, but you can probably
ask on the mplayer ML how you would implement this.  Basically just
ask them if you can send a video to two output windows at the same
time (one Xv and one Xshm). Depending on how intertwined the decoding
and output paths are in mplayer this may be easy or difficult.


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