[mythtv-users] [mythtv] MythTV Raspberry Pi2 frontend testers

[Lawrence Rust]

On Sun, 2015-11-22 at 08:51 -0800, Tom Harris wrote:
> On Thu, Nov 19, 2015 at 9:25 AM, Peter Bennett (cats22) <cats22 at comcast.net>
> wrote:
[snip]
> I took another run at it this weekend.  My results are similar to Peter’s
> 
> I first re-tried EGLFS mode:
> - wasn’t able to edit the settings on the Pi’s display, so I used remote X
> to change the settings and add an OpenMax profile
> - used rasp-config to change the memory split from 128MB of graphics mem to
> 256MB
> - confirmed my MPEG2 license was installed with “vcgencmd codec_enabled
> MPG2”  (the license code should be placed in /boot/config.txt)
> 
> After this, video actually plays on the Pi in EGLFS mode.  However, it was
> not smooth for either 1080i or 720p (US Broadcast MPEG2).  I got a lot of
> playback messages like:
> 
> 2015-11-22 15:59:43.219535 I  Player(1): Waiting for video buffers...
> 2015-11-22 15:59:43.282415 I  Player(1): Video is 3.19103 frames behind
> audio (too slow), dropping frame to catch up.
> 2015-11-22 15:59:43.284804 I  Player(1): Video is 3.11257 frames behind
> audio (too slow), dropping frame to catch up.
> 2015-11-22 15:59:43.285256 I  Player(1): Waiting for video buffers…

This looks like an A/V sync issue and appears to be similar to what
others have said.  I have configured audio for ALSA and have setup my
RPi's to output audio to the 3.5mm jack (none of my HDMI monitors have
speakers).  Try executing:
amixer cset numid=3 1 # 0=auto, 1=phono, 2=hdmi

> I then went to X, and started in xcb mode.   There the video playback was
> quite smooth.   But, my video was offset up+left, leaving black bars on the
> bottom and right of the screen.  I’m sure I can address that via overscan
> config and OSD settings.

The offset is puzzling.  Could you post the log from mythfrontend -v
playback --loglevel debug?

> My initial eglfs test was with HDMI audio with DD/5.1, which resulted in
> static-like sound.  After switching to stereo output, I could hear the
> audio track on my recordings.
> 
> Another data point:  I’ve also been testing MythTV in OpenElec/Kodi on this
> rpi2 device, and under Kodi the video playback is perfect.  I believe Kodi
> is doing EGL display.  So, that’s a good sign that the underlying hardware
> and software should be fully capable.

In testing I have found that OpenGL has a considerably higher overhead
than OpenMAX.  OpenMAX appears closer to the h/w.  This RPi branch also
supports OpenGL playback.  I would appreciate your feedback on that too.
In the OpenGL2 ES renderer I tried to minimise the CPU load by making
the GPU handle YV12 video directly instead of converting to YUVY but
even so the CPU overhead is at least twice that of OpenMAX.

-- Lawrence Rust