[mythtv-users] ECS Liva stuttering on some Channels

[Alan Walls]

Over the last week I switched to using an ECS Liva frontend but unfortunately I'm now getting lots of stuttering and audio sync drifting on some channels.  It appears that the Liva can handle SD and 1080i @ 30fps but can't handle 720p @ 60fps.  Does this match what others are seeing or have I setup something wrong?

I may have to switch back to my old Gen 1 ION Zotac frontend which worked fine with all channels.


Installation details and observations follow...

My capture cards are all over-the-air digital cards.  Some channels are marginal strength and do produce pixelation at times.  I saw no pixelation during these tests.

The TV is a 1080p Samsung.

I have default Xorg settings for the screen.  Are there any Xorg configuration parameters I should be using?

The installation was created from a MythBuntu .ISO, then upgraded to 15.04.  The frontend and backend have recent MythTV versions on them (v0.27.5-3-g9498257).  Nothing else is running on the frontend or backend.

I have installed vaapi.  The log looks like it loaded correctly.  vainfo reports "VA-API version 0.37.0" with "Intel i965 driver for Intel(R) Bay Trail - 1.5.1".  The Mythtv OSD playback data display shows vaapi being used.

Using OpenGl for playback didn't help.

Top is showing about 25-30% CPU usage to Mythfrontend during playback when using vaapi.  The next highest is 4-5% for Xorg.

The machine is a Frontend only.  The backend is an i5-3470 with 8GB ram.  Stuttering happens whether I am recording or not.  The mythbackend.log shows nothing.  I see nothing in syslog's.

The Liva is connected to a TV with HDMI(video+audio) via a stereo receiver.  I have audio set to stereo PCM audio.  Sound is using the alsa device, not the PulseAudio device.

Mythfrontend.log shows lots of "Waiting for video buffers" messages during stuttering.  Typically 100-200ms, often 1-3 seconds.

Both machines are connected to the same gigabit switch and ifconfig doesn't show any errors.

When stuttering happens the audio drifts ahead of the video.  Pressing forward then stop restarts and syncs the video/audio.

I have disabled memory swapping and removed the swap partition.

my data partition is ext4 with noatime set.  Disabling file logging made no difference.

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