[mythtv-commits] Ticket #6282: Audio/Video lagging on one particular HD digital channel.

MythTV mythtv at cvs.mythtv.org
Fri Feb 20 03:04:28 UTC 2009

#6282: Audio/Video lagging on one particular HD digital channel.
 Reporter:  Josh Winters <fuxxociety at gmail.com>  |       Owner:  ijr       
     Type:  defect                               |      Status:  new       
 Priority:  major                                |   Milestone:  unknown   
Component:  MythTV - Video Playback              |     Version:  0.21-fixes
 Severity:  medium                               |     Mlocked:  0         
 Hello everyone. I've been doing a LOT of searching, but found no real

 When tuning a particular HD channel (specifically, KRIV Houston Digital),
 the audio and video start out fine, but after about 1 second of smooth
 playback, both audio and video are extremely choppy. 'mythfrontend -v
 playback' reports lots of "NVP: Video is 14.21 frames ahead of audio,
 doubling video frame interval to slow down."

 That leads me to suspect that the video rendering isn't the issue, it's
 the audio playback. I tested by disabling audio in the frontend (by
 selecting the NULL audio device)

 Once audio was disabled, the affected channel played back BEAUTIFULLY. No
 dropped frames, no lag, no error messages in the frontend.

 I have seperate backend/frontends also, so no tuner card sharing an IRQ.

 My frontend is a Core2Quad Q6600, running on an ASUS P5N7A-VM mobo, with
 1GB Samsung DDR2
 Distro: Gentoo linux

 I also have an Ubuntu laptop running mythfrontend, the laptop plays the
 affected channel beautifully (with sound!)
 Laptop specs: Toshiba X205-sli4 - Core2Duo T8100, 2x 8600M GT's, 3GB RAM

 Anyone have any ideas?
 Uploading a test clip to megaupload now, will reply with the URL.

Ticket URL: <http://svn.mythtv.org/trac/ticket/6282>
MythTV <http://www.mythtv.org/>

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