[mythtv-users] video stutter with VDPAU and 1080i DVB

[Justin Smith]

Hi,

I get a slight but annoying stutter in video playback of live TV on my 
mythTV box and I was wondering if anyone had any ideas on how to 
troubleshoot this. It only occurs for one 1080i HD DVB channel - other 
HD channels are fine (FWIW: Ch9 HD in Australia).

The stuttering is confirmed in the frontend log (-v playback) with lines 
like this:

NVP(6): Video is 3.19567 frames behind audio (too slow), dropping frame 
to catch up.

When I set the audio output device to NULL, the stuttering (and log 
lines) disappear. But as I'm not too good at lip reading... :)

I have gone through the prebuffering page on the mythtv wiki without 
success.


MythTV Config
* Frontend: MythBuntu Karmic 9.10 0.22 fixes 23084 (daily builds)
* Nvidia driver: 185.18.36
* Video Playback Profile: VDPAU High Quality
* Separate video modes for GUI & TV Playback: ON
* Audio output device: Default
* Passthrough output device: Default
* Max Audio Channels: Stereo
* Upmix: Passive
* AC3/DTS to SPDIF passthrough: both OFF
* Aggressive Sound card Buffering: OFF
* Extra Audio Buffering: ON
* Enable realtime priority threads: OFF
* Use video as timebase: OFF
* OpenGL vertical sync for timing: ON


Frontend Hardware Config
* Motherboard: Asus M4N78-AM
* CPU: AMD Phenom II X2 550
* Video: NVIDIA GPU GeForce 9500 GT (G96) fanless
* RAM: 2GB
* TV: Sony Bravia W5500 1080p


Changing the Video Playback Profile to any of the VDPAU options made no 
difference (including Slim).

The following also made no difference:
* Added Option "TripleBuffer" "True" to the device section of xorg.conf.
* Increasing the minimum CPU frequency from 800MHz to 1.8GHz.

Any help greatly appreciated.


Cheers,
Justin.