[mythtv-users] Good TV Out (long -sorry)

[Bruce Markey]

Chris Martin wrote:
...
> The live Tv quality on the Pundit-R is more than acceptable, providing
> bob deinterlacing is used. Unfortunately using bob deinterlacing
> casues the picture to get jittery and flickery with time, to the point
> that after about 5 minutes it is unwatchable. Quickly pausing and
> unpausing the picture resolves the problem but only for 5 minutes at

This is what I call a 'straddle' event. If there is no retrace
timing for the card, the frame buffer is updated at equal frame
intervals unaware of when the actual retraces will occur. If the
update and retrace are at almost the exact same time, the update
could happen just before or just after the retrace deadline. This
causes rapid jitter until they go out of sync again (pause would
accomplish this). Ironically, the more accurate the timing, the
longer these events last.

> which point the flickeryness returns.  I've been advised by somebody
> on the mailing list to use Open GL as this should provice VSync
> support which will resolve the problem.  At the time I thought I might
> not have open gl support, however the open gl picture transitions in
> myth gallery worked fine so maybe I do.

Both OpenGL and DRM methods will get the retrace timing and can
avoid this problem.

--  bjm