I'm using ffmpeg's x11grab to do some screencasting. It works pretty well except on 3D stuff. In particular it seems like 3D draw areas flicker in and out. You can see an example of it here.

The issue is present even when I capture only the screen (i.e., not adding in all the other fancy stuff and the webcam capture).

I've done a lot of googling on this issue and have found people with a similar issue, but no solution. Many suggest that it is due to OpenGL rendering directly to the hardware and bypassing X11 entirely.

Does anyone know of a way to deal with this? If it matters I'm using an nVidia graphics card.


I finally resolved it! The problem was to do with OpenGL as I suspected. To solve the issue, I downloaded VirtualGL. Specifically I grabbed the .deb file from here and installed it with dpkg.

Running my applications with vglrun application and then starting the screencast now works perfectly, it even runs more smoothly than it did without vgl.

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