Re: [Bino-list] Video sync on 2-GPU passive stereo

[Martin Lambers]

Hi Stefan!

Sorry for the late answer...

On Thu, 31 May 2012 10:01:16 +0200, Stefan Eilemann wrote:
> Right now I'm debugging an issue with the latest HEAD of bino, and I
> need at least a few pointers. Our setup uses two GPUs to drive a
> passive stereo,  Full HD projection. During playback, the left and
> right eye occasionally show incoherent frames. I verified this by
> using the same movie for both eyes. Whenever the movie playback is
> stopped, the two images match perfectly. The movie is a FullHD
> loss-less H.264, so frame drops are possible. The display outputs
> have a refresh rate of 25Hz, which matches the movie framerate. My
> command line is:
> 
> env __GL_SYNC_TO_VBLANK=1 ./src/bino -i
> separate-left-right /media/left/2012.02/BBP_Movie_25_MPEG-4_Left.mp4 
> /media/left/2012.02/BBP_Movie_25_MPEG-4_Left.mp4
> -o equalizer --eq-config movie.eqc -b

I cannot reproduce the problem here. I currently don't have access to a
machine with two graphics cards so I configured both pipes on device 0,
but this should not make a difference. Both output windows are always
in sync, also when seeking, even though I also have frame drops.

Maybe this has something to do with config::startFrame() only being
called 25 times per second? Can you try with sync-to-vblank disabled?

A question about movie.eqc (probably unrelated): Why is the appNode
configured without graphics output, and a separate node is configured
for the two graphics cards?

> PPS: I checked in some simplifications in player_equalizer.cpp

Thank you!

Martin