[mythtv-users] Strange "choppy" video during playback

[OJ]

I'm experiences the problem both during LiveTV and DVD playback.
Possibly others also, but not tested yet.

This "chopping" happens every 2 min, and lasts 1-3 sec.

I'm not sure what introduced this, but since I last had it working I
have changed from nVidia 6200 GPU to an ATI 4850 GPU. In addition I
have updated to trunk all along.

Due to what seems like a bug with the fglrx driver from ATI had did as
described in the 2nd post here:
http://forums.dvbowners.com/index.php?showtopic=10431

I haven't seen anything suspicious in the frontend logs, but on the
backend I see a pattern, but I don't know if it relevant.
(the logs are from LiveTV)
When this sequence is on the backend there is "chopping"
2008-11-15 11:27:14.437 JobQueue: Currently set to run up to 1 job(s) max.
2008-11-15 11:27:14.438 JobQueue: GetJobsInQueue: findJobs search
bitmask 4, found 0 total jobs
2008-11-15 11:27:39.338 AutoExpire: Adding Programs to 'Do Not Expire' List
2008-11-15 11:27:39.338     1429 @ 2008-11-15T11:19:16 in use by
player on stuepc

When this sequence is on the backend there is _not_ "chopping"
2008-11-15 11:28:14.439 JobQueue: Currently set to run up to 1 job(s) max.
2008-11-15 11:28:14.440 JobQueue: GetJobsInQueue: findJobs search
bitmask 4, found 0 total jobs
2008-11-15 11:28:41.105 AutoExpire: Adding Programs to 'Do Not Expire' List
2008-11-15 11:28:41.105     1429 @ 2008-11-15T11:19:16 in use by
player on stuepc
2008-11-15 11:28:41.105 AutoExpire: ExpireLiveTV(10000)
2008-11-15 11:28:41.105 AutoExpire: FillDBOrdered: Adding Short LiveTV
programs in starttime order
2008-11-15 11:28:41.106 AutoExpire: SendDeleteMessages. Nothing to expire.

When this sequence is on the backend there is "chopping"
2008-11-15 11:29:14.440 JobQueue: Currently set to run up to 1 job(s) max.
2008-11-15 11:29:14.440 JobQueue: GetJobsInQueue: findJobs search
bitmask 4, found 0 total jobs
2008-11-15 11:29:41.107 AutoExpire: Adding Programs to 'Do Not Expire' List
2008-11-15 11:29:41.107     1429 @ 2008-11-15T11:19:16 in use by
player on stuepc

Any tips on how to solve it, or what could be causing this?

A few I have managed to avoid it the problem. I have started the
backend and frontend with different verbose options, but I don't know
if this is what is causing it or something else.