[mythtv-users] Trouble with HD playback

Michael S. Keller samsara at tulsaconnect.com
Mon Nov 1 23:26:28 UTC 2004

> Xv helps, but a ton is still done in hardware. XvMC does a whole lot more in 
> hardware, but doesn't look as good (and places other limitations on what you 
> can do w/your output in Myth). However, judging from the guy who is able to 
> play back those HD clips on a 1.4GHz Celery w/a GF FX 5200 and XvMC, it does 
> help out a ton, so you might try that w/your onboard graphics...

That was me. Once my cards arrive, if I can get the automatic transcode 
to produce satisfactory results, I should be happy. So far it's a 
problem, because A/V sync is off after transcoding to MPEG4 (regardless 
of MPEG2 source), it's no longer using XvMC and the aspect ratio is 
wrong. It stutters even when I drop the transcode bitrate to lowest 

> DVDs are 720x480, HDTV (in its two best forms) is 1280x720 or 1920x1080. That 
> ABC clip is 1280x720, the CBS clip is 1920x1080.

The ABC clip played fine. The CBS clip's audio was a bit off and it 
wasn't scaled right (1/4 to 1/3 of the image was missing off the right 
side), but what I could see was smooth and the A/V sync was good. In 
both cases, bringing up the OSD brought immediate stutter and the only 
way to clear it was to save position, exit and play again.

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