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consider upgrading if necessary. Another problem I experienced

early on was that playing recordings or DVDs consumed such a

large fraction of CPU time (70%–80%), that running other

processes tended to cause the playback to become jerky. In

particular, commercial flagging and database accesses at the

beginning and end of recording a program produced annoying

jerkiness. I resolved this problem entirely by replacing my ATI

video card, which does not have a proprietary Linux driver,

with an NVIDIA card. The skipping stopped almost completely

when I replaced the video card, as did the seemingly unrelated

problem of slow menu scrolling. CPU usage dropped to

around 40%–50%.

Another benefit of NVIDIA’s superior Linux support is that

part of the MPEG decoding work can be delegated to the

video card using XvMC (X-Video Motion Compensation),

reducing the load on the CPU. To enable XvMC, go to

Utilities/Setup→Setup→TV Settings→Playback. On the

third screen, change the Playback Profile to CPU--. XvMC

didn’t kick in on mine until I deleted the top line of the

profile (referring to ivtv). You can tell if it’s operating

because the on-screen display changes to grayscale. You

also can tell because the CPU usage will go way down. The

Xorg process dropped to less than 10% during playback;

the sum of Xorg and mythfrontend is always less than

30%. As a result, additional processes (including creating

and burning DVDs) no longer affected playback.

Satisfaction

For a pretty small sum—$85 if you get a tuner card on sale

and already have a computer and up to around $500 for a

multicard, multidrive system built from scratch—you can

build a fully functional MythTV box. TV watching will never

be the same.

Be warned: MythTV is an amazing piece of software, but

it is free software that is constantly under development. Be

prepared to get your hands dirty and tinker under the hood

if something goes wrong or everything isn’t working as you’d

like. Have fun with it—test-drive different themes, tweak the

settings and try the various plugins. After all, that’s what Linux

is all about.

P. Surdas Mohit is a postdoctoral fellow at the Institute of Geophysics and Planetary Physics at

Scripps Institute of Oceanography.

Resources

MythTV:

www.mythtv.org

Hauppauge WinTV-PVR Tuner Cards:

www.hauppauge.com/site/products/prods_pvr.html

Mythbuntu:

www.mythbuntu.org

How to Install an IR Blaster: