XVMC

Without actually knowing what XVMC actually is, XVMC is the X11 interface to MPEG playback hardware on modern video cards. NVidia is the only brand of cards that people talk about using it with, I’m not sure if that’s just because NVidia are the only people to write drivers for it or what.

I finally got around to getting xvmc working with mythtv, and on my woefully underpowered system it makes all the difference in the world: live TV is stutter free (the front end no longer pauses to buffer input) and the CPU usage is down to around 40% when displaying a 460×480 picture.

There was a fair bit of stuffing around involved as I eventually discovered that XVMC and TwinView (an NVidia configuration option that allows the Monitor and TV to display the same image) don’t work together, only one display can use the MPEG hardware at one time. The NVidia documentation came to the rescue again, however, and walked me through setting up the TV and Monitor to be separate screens on the same display, such that the TV is :0.0 and the Monitor is :0.1, which lets the myth frontend use the MPEG hardware.

I also setup the NVidia AGP driver, it seems to provide some marginal improvements.

All in all, the current setup is almost usable. The picture on the TV is not full sized, or particularly smoothly rendered.

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