[mythtv-users] Audio/Video sync issues

John Pilkington johnpilk222 at gmail.com
Mon Feb 11 11:10:59 UTC 2019

On 11/02/2019 04:38, Bob wrote:
> All of a sudden my FE/BE system has an audio/video sync issues. I 
> haven't changed anything. I'm using an NVidia 710 card with an HDMI 
> connection to a home theater receiver with VDPAU decoding.
> As I watch a recording, it appears the audio gets farther and farther 
> behind so adjusting the delay doesn't help for long.
> I have a another frontend that can play the same recordings without 
> issue (via LAN).
> 2019-02-10T09:38:40.835507-07:00 mythfrontend[3322]: C thread_unknown 
> mythcommandlineparser.cpp:2619 (ConfigureLogging) mythfrontend version: 
> fixes/29 [v29.1-38-gb9c5f8b2ff] www.mythtv.org
> 2019-02-10T09:39:13.189410-07:00 mythfrontend[3322]: N CoreContext 
> audioplayer.cpp:167 (ReinitAudio) AudioPlayer: Enabling Audio
> 2019-02-10T09:39:13.590746-07:00 mythfrontend[3322]: I CoreContext 
> audio/audiooutputbase.cpp:823 (Reconfigure) AOBase: Opening audio device 
> 'hdmi:CARD=NVidia,DEV=1' ch 6(6) sr 48000 sf signed 32 bit reenc 0
> 2019-02-10T09:39:14.191448-07:00 mythfrontend[3322]: E CoreContext 
> audio/audiooutputalsa.cpp:915 (OpenMixer) ALSA: failed to register mixer 
> device /dev/mixer: No such file or directory
> 2019-02-10T09:39:14.191606-07:00 mythfrontend[3322]: E CoreContext 
> audio/audiooutputalsa.cpp:498 (OpenDevice) ALSA: Unable to open audio 
> mixer. Volume control disabled
> 2019-02-10T09:39:14.292337-07:00 mythfrontend[3322]: N CoreContext 
> mythplayer.cpp:532 (CheckExtraAudioDecode) Player(0): Forcing decode 
> extra audio option on (Video method requires it).
> 2019-02-10T09:39:14.393024-07:00 mythfrontend[3322]: E CoreContext 
> mythplayer.cpp:2493 (VideoStart) Player(0): Video sync method can't 
> support double framerate (refresh rate too low for 2x deint)
> 2019-02-10T09:39:14.393135-07:00 mythfrontend[3322]: I CoreContext 
> mythplayer.cpp:1832 (InitAVSync) Player(0): Video timing method: USleep 
> with busy wait
> 2019-02-10T09:39:14.393306-07:00 mythfrontend[3322]: I CoreContext 
> tv_play.cpp:5864 (StartPlayer) TV::StartPlayer(): Created player.

Perhaps you're seeing another aspect of this; see the last paragraph.


"There is a bug with VDPAU rendering. Certain channels in the USA...."

Over the past few months Master has had various changes related to 
AVsync and it seems they haven't yet been finalised.  I haven't seen a 
problem here in the UK - with a GT710.

John P

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