[mythtv-users] HD Recordings on Regular TV

Robert Macaulay robert.macaulay at gmail.com
Fri Apr 27 04:59:50 UTC 2007


> myth 0.20 from atrpms(build 155), nvidia 9631(yes, legacy). Xorg
> 7.1.1, KDE window manager. glx disabled
>
> and I'm currently performing this on mythfront start
> /usr/bin/nvidia-settings --assign="XVideoBlitterSyncToVBlank=0" \
>         --assign="XVideoTextureSyncToVBlank=0" \
>         --assign "SyncToVBlank=0"
>
> The glx disablement and the nvidia-settings were all grasps at
> stability(various mailing list posts).. I had a brief but
> wife-alienating lockup series of events where watching live TV would
> lock up X(ie, reboot time). This was in the XvMC days as well.
>

More info:
* Linux mythbackend 2.6.20-1.2944.fc6 #1 SMP Tue Apr 10 17:46:00 EDT
2007 x86_64 x86_64 x86_64 GNU/Linux
* Content was HD recording from HDHomeRun
* Deinterlacing. Even though this is a SDTV, w/out interlacing, I saw
the effects when watching tv. Pans would have horizontal lines across
them where the frames weren't lines up. Either way, turning that off
solved nothing
* Also tried Standard vs the lib MPEG decoder(the non XvMC one). No difference.
* Re-enabled all the default settings in nvidia-settings(vsync, etc).
* re-enabled glx
* running at "720x480" now. Much cleaner picture. Still have same
playback issues though.
* realtime threads enabled and working
* was using a spdif alsa config to enable softvolume. Disabled that.
Output now just going through normal alsa channels(just the rate dmix
plugin active). Either way, its AC3 audio, so the passthrough setting
straight to the SPDIF works eliminating any system processing. Amp
goes into digital mode properly.
* XvMC did allow proper playback, but at cost of instability(this is a
backend/frontend box. Locking up is bad).

The cpu is split 75% mythfrontend and 25% Xorg. No io waits. About 5%
in system, the other 95% is user space.

Watching same content on a slightly more powerful remote frontend
box(3200+) via vga(1360x768) results in if I recall about 50-60%
usage.


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