[mythtv] XVideo XvMC VLD broken

Daniel Kristjansson danielk at cat.nyu.edu
Tue Apr 26 12:23:03 UTC 2005


On Tue, 2005-04-26 at 06:34 +0100, Terry Barnaby wrote: 
> > Hmm, do you know who wrote the VLD part of avcodec?
> Yes, it was me :)
:)

> If you look at my "bug1" log from a few emails back, you will see
> that "something" is calling av_remove_stream() on a channel change
> when TS streams are in use. av_remove_stream() does not appear to be
> called when PS streams are in use ...

Ah, but this isn't being called by us because of the channel change, it
is being called from within avlib because the PMT has changed. This
can happen at any time, regardless of whether the channel has changed.
I think Doug had a test stream where the PMT changed every few seconds.
HDTVRecorder also has a "WHACK_A_BUG_VIDEO" define you can use to debug
this (assuming you can record/playback HDTV).

> Maybe the "DVB channel changing problems" you refer to is due
> to some problem with av_remove_stream() and the VBuffer system ?
> I don't intend to make any VLD changes but will investigate a
> little more ...

It is possible, but all it does currently is stop listening for data
on a stale TS stream, it doesn't even close the old av codecs, it just
opens new ones for the new data streams. I have a patch to actually
delete the codecs but that causes problems for nVidia XvMC I haven't
tracked down yet.

-- Daniel



More information about the mythtv-dev mailing list