[mythtv-users] Jerky playback

Clyde Stubbs clyde at htsoft.com
Thu Dec 4 00:19:56 EST 2003


While watching live tv or playing back recordings, the display is jerky.
For example, a news ticker across the bottom of the screen pauses about
every second for a fraction of a second. It's also obvious with moving
things on screen. I'm not sure whether there are frames being lost, or
just that the frame display rate is not constant, but I suspect the latter.
I.e. I suspect that the rate of frame update is faster than it should be,
and the pauses are "catch-up".

Streaming video from the card to mplayer or xine does NOT produce the
same effect.

In addition, if the playback is paused then resumed, sometimes there seems
to be a problem with out-of-order frames. For example, people's heads
will flick to one side, or when a scene change occurs, there will be a flash
of the new scene, then back to the old scene, then the change to the new
scene actually occurs. This only occurs after pausing. Escaping out then
restarting playback makes this go away.

Setup is:

Athlon XP2400+
nforce2 mb
512MB
200GB IDE (dma IS on)
RH9 w/ 2.4.22 kernel
XFree86 nv driver (can't use NVidia driver due to lack of interlacing for TV-out)
display 800x600 @ 50Hz interlaced on PAL TV
Nebula DigiTV card
CVS Mythtv

CPU usage during live tv runs around 55%. Much of this is used by X.
I have tried jitter reduction on or off (no difference)
and the experimental A/V sync (unusable - completely screwed up A/V sync)
Playback and recording settings are otherwise at their defaults.

any suggestions?



-- 
Clyde Stubbs                     |            HI-TECH Software
Email: clyde at htsoft.com          |          Phone            Fax
WWW:   http://www.htsoft.com/    | USA: (408) 490 2885  (408) 490 2885
PGP:   finger clyde at htsoft.com   | AUS: +61 7 3552 7777 +61 7 3552 7778
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