Mailing List Archive

Mythtv-frontend operation with 4K TV?
I know that mythfrontend on an x86_64 Linux PC works at 4KP60 resolution
on a UHD TV and seems to perform well. However, is that really the best
way to run it.  Is there any advantage to forcing the PC to
1920x1080@60Hz before launching mythfrontend?

The reason I ask is that I've been fighting a problem with having
multiple source devices connected to my 4K UHD Samsung TV.  My current
solution is to use a 5x1 HDMI 2.0 4Kp60 switch with all devices plugged
into the switch and the switch connected to one of the TV's HDMI input
and the Samsung's setting set to HDMI 2.0 so all the modes will work for
my input devices, like the Raspberry Pi. Nvidia Shield TV and Nvidia
GT1030 video card in a PC.

I have 2 choices with my PC setup when using it from across the room
because I need to set the resolution bigger than 4K yields. I can do
that with either 1080P mode in the Display settings app or using the
native 4KP60 mode with the Appearance app set to 2x on the scaling of
the desktop.

Since the HDMI switch moves the connections from the different input
devices, the PC seems to be sensitive to that and switches back to 4K
mode if I had it set to 1080P mode. So my current choice is to leave the
PC setting for display at 4Kp60 so the switch has no affect on the
display as long as I keep the scaling at 2x for view usability.

So that leaves me wondering about my original question, is there any
advantage to forcing the PC to 1080P mode before launching mythfrontend
vs. leaving it in native 4K mode. The Nvidia GT1030 seems to not care as
the picture looks fine either way.

Jim A


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Re: Mythtv-frontend operation with 4K TV? [ In reply to ]
I'm not an expert, but the only advantage of using a lower resolution
would be to reduce the workload on the video card. But as you said,
the 1030 can handle 4k content just fine. I have a 1030 GT myself
with a 4K display and I've had it set to 4k for a while now. I did have
it set to 1080 initially, but that was because my MythTV system seemed
to struggle keeping up. The problem was that I didn't have my Nvidia
settings correct for Xorg, and it was actually doing software rendering.
Once I fixed the config, it's been just fine at 4k.

My vote, leave it at 4k.

-Erik

On Wed, Sep 9, 2020 at 8:12 AM Jim Abernathy <jfabernathy@gmail.com> wrote:

> I know that mythfrontend on an x86_64 Linux PC works at 4KP60 resolution
> on a UHD TV and seems to perform well. However, is that really the best
> way to run it. Is there any advantage to forcing the PC to
> 1920x1080@60Hz before launching mythfrontend?
>
> The reason I ask is that I've been fighting a problem with having
> multiple source devices connected to my 4K UHD Samsung TV. My current
> solution is to use a 5x1 HDMI 2.0 4Kp60 switch with all devices plugged
> into the switch and the switch connected to one of the TV's HDMI input
> and the Samsung's setting set to HDMI 2.0 so all the modes will work for
> my input devices, like the Raspberry Pi. Nvidia Shield TV and Nvidia
> GT1030 video card in a PC.
>
> I have 2 choices with my PC setup when using it from across the room
> because I need to set the resolution bigger than 4K yields. I can do
> that with either 1080P mode in the Display settings app or using the
> native 4KP60 mode with the Appearance app set to 2x on the scaling of
> the desktop.
>
> Since the HDMI switch moves the connections from the different input
> devices, the PC seems to be sensitive to that and switches back to 4K
> mode if I had it set to 1080P mode. So my current choice is to leave the
> PC setting for display at 4Kp60 so the switch has no affect on the
> display as long as I keep the scaling at 2x for view usability.
>
> So that leaves me wondering about my original question, is there any
> advantage to forcing the PC to 1080P mode before launching mythfrontend
> vs. leaving it in native 4K mode. The Nvidia GT1030 seems to not care as
> the picture looks fine either way.
>
> Jim A
>
>
> _______________________________________________
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> MythTV Forums: https://forum.mythtv.org
>
Re: Mythtv-frontend operation with 4K TV? [ In reply to ]
There are potentially a couple of advantages to running at 1080p.

Firstly any 4k TV worth its salt will do a better job of upscaling 1080
and/SD content than most media players. This is largely due to better,
dedicated hardware. If you feed it 4K it can't do much scaling wise.

Secondly, with the way mythtv rendering works at the moment, displaying
both the UI and video at 4K is going to work the system harder - both in
terms of gpu load and memory consumption. Admittedly it's probably not
enough to be an issue on a modern, desktop system but will be relevant on
less capable hardware (e.g. pi4 etc). All the current mythtv themes are max
1080 by design and scaling them up could be better handled in hardware -
it's something on my to-do list.

I would recommend enabling resolution switching , set both the UI and video
resolution to 1920*1080 and use 'auto' for refresh rate matching. If you
have some 4k content then add an override for that as well.

(Note: display mode switching should work with 'regular' Linux and macos
setups but is limited or not implemented in other cases e.g. no pure
Wayland support in .31, raspberry pi without X can only switch refresh
rate, other Linux without X no support)

Regards
Mark
Re: Mythtv-frontend operation with 4K TV? [ In reply to ]
On 9/10/20 3:59 AM, Mark Kendall wrote:
> There are potentially a couple of advantages to running at 1080p.
>
> Firstly any 4k TV worth its salt will do a better job of upscaling
> 1080 and/SD content than most media players. This is largely due to
> better, dedicated hardware. If you feed it 4K it can't do much scaling
> wise.
>
> Secondly, with the way mythtv rendering works at the moment,
> displaying both the UI and video at 4K is going to work the system
> harder - both in terms of gpu load and memory consumption. Admittedly
> it's probably not enough to be an issue on a modern, desktop system
> but will be relevant on less capable hardware (e.g. pi4 etc). All the
> current mythtv themes are max 1080 by design and scaling them up could
> be better handled in hardware - it's something on my to-do list.
>
> I would recommend enabling resolution switching , set both the UI and
> video resolution to 1920*1080 and use 'auto' for refresh rate
> matching. If you have some 4k content then add an override for that as
> well.
>
> (Note: display mode switching should work with 'regular' Linux and
> macos setups but is limited or not implemented in other cases e.g. no
> pure Wayland support in .31, raspberry pi without X can only switch
> refresh rate, other Linux without X no support)
>
> Regards
> Mark
>
Mark,

Thanks for the recommends. I have noticed that 1080P content looks
better on my 4K TV when the TV is setup automatically with all the
enhanced features turned on like HDR, etc.

I've also notices that the RPI4 goes out of it's way with the pi-utils
scripts to keep it's resolution at 1080P with no desktop; and that seems
to work better with 64bit RPI OS than 32bit with my current testing, but
that could be because of the more current version number you get when
building from source.

I have found a setting in Xubuntu that, if turned off, will keep the
display at 1080P when the HDMI switch is moved away from the PC and then
back.

All my 4K content comes from Netflix and Prime Video and run on the
Nvidia Shield TV so no issues with the PC.

I think I'm in the final stages of troubleshooting my Frontend problems.
The keys I think have been.

1. Eliminating my 8 yr. old Denon AV Receiver from the the video chain
because of it's 4K30 limit, and replacing with HDMI 2.0 5x1 switch.

2. Removing the USB3 memory stick from the Nvidia Shield TV (This was a
bitch to find and caused very peculiar problems with the Android version
of mythfrontend)

3. Setting the TV to HDMI 2.0 enhancements.

Thanks again,

Jim A



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Re: Mythtv-frontend operation with 4K TV? [ In reply to ]
>
> I have found a setting in Xubuntu that, if turned off, will keep the
> display at 1080P when the HDMI switch is moved away from the PC and then
> back.
>

Jim, can you share this setting? I have similar issues with one of my
frontends.
Re: Mythtv-frontend operation with 4K TV? [ In reply to ]
On Thu, Sep 10, 2020 at 6:06 AM John Hoyt <john.hoyt@gmail.com> wrote:

> I have found a setting in Xubuntu that, if turned off, will keep the
>> display at 1080P when the HDMI switch is moved away from the PC and then
>> back.
>>
>
> Jim, can you share this setting? I have similar issues with one of my
> frontends.
>
> First a warning; my system was originally installed with Ubuntu 20.04 and
Xubuntu Desktop was added so sometimes I have both Desktop environment
settings fighting each other.
With that said I found that the xfce4 Advanced setting, Configure new
display when connected needs to be turned off.
https://docs.xfce.org/xfce/xfce4-settings/4.14/display
Re: Mythtv-frontend operation with 4K TV? [ In reply to ]
On Thu, Sep 10, 2020 at 6:16 AM James Abernathy <jfabernathy@gmail.com>
wrote:

>
>
> On Thu, Sep 10, 2020 at 6:06 AM John Hoyt <john.hoyt@gmail.com> wrote:
>
>> I have found a setting in Xubuntu that, if turned off, will keep the
>>> display at 1080P when the HDMI switch is moved away from the PC and then
>>> back.
>>>
>>
>> Jim, can you share this setting? I have similar issues with one of my
>> frontends.
>>
>> First a warning; my system was originally installed with Ubuntu 20.04 and
> Xubuntu Desktop was added so sometimes I have both Desktop environment
> settings fighting each other.
> With that said I found that the xfce4 Advanced setting, Configure new
> display when connected needs to be turned off.
> https://docs.xfce.org/xfce/xfce4-settings/4.14/display
>
> Maybe an update is in order. I went back and tested this with my display
set to 1080P and found that switching away and then back using the 5x1 HDMI
switch made the display jump to 4KP.

I now have it staying in 1080P mode when switching by these steps:
1. configure the display to 1080P
2. In the Advanced setting referred to in the link above, create a profile
for the display.
3. Turn On the 2 connecting display options.

When I switch away from the PC to another HDMI input it is working now. But
I'll switch away again and go get more coffee and see what it does when I
come back

Jim A