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

James Abernathy jfabernathy at gmail.com
Mon Feb 5 14:38:00 UTC 2024


On Mon, Feb 5, 2024 at 8:29 AM Jay Harbeston <jharbestonus at gmail.com> wrote:

>
>
> On Feb 4, 2024, at 3:54 PM, James Abernathy <jfabernathy at gmail.com> wrote:
>
>
>
> On Sun, Feb 4, 2024 at 11:08 AM Jay Harbeston <jharbestonus at gmail.com>
> wrote:
>
>>
>>
>> > 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.
>
>
> The machines that I have been using are able to display on a 4k monitor/TV
> however, I have not had good success with full screen tv from mythtv when
> using 4k upscaling. I have always dropped the tv back to 1080p mode 60hz
> and have had good luck with them then. All the content I have is either
> BluRay 1080p, or standard atsc resolutions so running the tv in 4k doesn’t
> matter  as far as the display. The machines I use have been either intel
> N95/N100 or N5095/N5195 machines, and playback using VAAPI/VAAPI2 profile
> on all of them.
>
> I see you have been ’toying’ with the ATSC 3 in the past. Has there been
> any 4K content on ATSC3 in your area? Are you able to record from ATSC3
> using mythtv either 1080p/I or 4k?
>
> Regards!
>
>
My UHD TV is a Sony middle grade 4K TV with ATSC 3.0 tuner builtin.   Its
image processor is so good that 1080P content looks so close to 4K that I
can't tell any difference. I have seen some 4K content but only streaming.
The local TV stations in the Raleigh, NC market all have ATSC 3.0 channels,
but they are all limited to 1080P or 720P and they are using the new audio
standard.  I have not purchased an ATSC 3.0 tuner yet so I can't answer
anything about Mythtv and 4K. I keep up with "Antenna Man" and "Lon.TV"
youtube channels who do a good job of updating everyone in the USA about
ATSC 3.0 and the mess that turning DRM on in some markets has caused.  I
have no idea if my market has DRM enabled or not since I have a Sony TV and
I'd imagine that they are on top of DRM issues.

I'm told that since the FCC repack a few years ago, there isn't enough
bandwidth for a station to do both ATSC 1.0 and ATSC 3.0 in 4K. Even one
channel in 4K would cause them to limit the number of sub channels they
could have. Since the FCC isn't forcing the move like they did on analog to
digital, It will be long after I'm gone before ATSC 3.0 is something I have
to move to.

Based on the crap I've seen and heard, ATSC 3.0 is a long way from pushing
out ATSC 1.0.  The lack of 4K in most markets on ATSC 3.0 is not helping.
So the only advantage for some who've played with it is the fact that the
ATSC 3.0 signal encoding is helping reduce signal ghosting effect of the
receivers getting confused processing the signals.  I learned this on those
youtube channels.  For me as I live only 10 miles from the TV towers, I
have no issues except maybe too strong a signal. I still get breakups of
pictures when the wind moves the trees too much.  I have to point my
antenna off-channel so I can get a PBS station 35 miles away as well as the
local tower channels.

JIm A
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