[mythtv-users] jittery playback on latest v34 (master) on Intel 11th gen Core i7 NUC.

James Abernathy jfabernathy at gmail.com
Sun Feb 4 20:54:45 UTC 2024

On Sun, Feb 4, 2024 at 11:08 AM Jay Harbeston <jharbestonus at gmail.com>

> > On Feb 4, 2024, at 9:06 AM, James Abernathy <jfabernathy at gmail.com>
> wrote:
> >
> > I don't normally use a PC as a frontend.  However, today I was on my NUC
> which is running Linux Mint Debian Edition 6. I'm using the mythfrontend on
> V34 Master that I built the packages for this morning following the Wiki.
> The NUC PC is an Asrock NUC 1165G7 which uses an Intel 11th gen Core i7 CPU.
> >
> > I noticed a lot of jitters playing a recording that was 1080i ATSC 1.0
> MPEG2. I tried both Opengl High quality and VAAPI with the normal settings
> I've used in the past. Too jumpy a picture to watch this way. I originally
> viewed the recording using Leanfront on a FireTV 4K Max.
> When it was jumpy, did you try using the menu->playback -> info to see
> what decoder was being used, and the load on the cpu?
> I suspicion that for whatever reason the accelerated video method isn’t
> getting used. Or the settings for de-interlacing are wrong somehow.
> Regards!
Thanks, I have more data, but first to your questions.

When in OpenGL High Quality, the playback data shows the Codec/dec as MPEG2
ffmpeg with Deint as 2x GLSL Kernel
when in VAAPI either Decode only or normal, Codec/dec is MPEG-2 VAAPI-dec
with deint as 2x VAAPI compensated.

Same jitter in both.

So I went looking for issues with the system in general. vlc has the same
jitter playing the file. Kodi is cleaner but not as good as my FireTV 4K
with leanfront.

I've been running LDME6 in default X11 mode on a 4K UHD display in 4K with
a 200% scaling factor.  That works well except for mythtvfrontend and gives
me the option to play 4K content when available outside of mythtv
recordings which are only HD.

If I change the resolution to 1920x1080, it picks 120Hz and that works well
and mythfrontend is better on OpenGL.

vlc is now better matching mythfrontend quality.  Same as Kodi now. All of
these are usable.

So maybe the scaling is the problem. Maybe X11 or Cinnamon DE with 200%
scaling is a little past the limits of my NUC?

Since my normal viewing of mythtv recordings on this UHD TV is with a
FireTV 4K Max and Leanfront app, this mythfrontend on the NUC issue is not
a huge problem. More of a curiosity. Not sure I really need the PC in 4K
mode since I sit >10ft from the screen. So I'll try switching to 1080P
resolution instead of 200% scaling of the default UHD resolution.

I tested this on an AMD desktop with a 8 core Ryzen with builtin gfx and
that had no issues, but it's a faster CPU and good gfx and the monitors are
only 1080p.

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