[mythtv-users] Video and sound turning off for 2 seconds then returning

James Abernathy jfabernathy at gmail.com
Sun Jul 25 15:04:36 UTC 2021


On Sun, Jul 25, 2021 at 10:24 AM Stephen Worthington <
stephen_agent at jsw.gen.nz> wrote:

> On Sun, 25 Jul 2021 09:17:35 -0400, you wrote:
>
> >
> >On 7/25/21 8:18 AM, Stephen Worthington wrote:
> >> On Sun, 25 Jul 2021 07:27:16 -0400, you wrote:
> >>
> >>> This problem is most likely caused by changing HDMI inputs away from my
> >>> PC and then back again. It's more subtle than it was a few years ago
> >>> when I was chasing this on 1080P.
> >>>
> >>> I've recently tried setting my PC to UHD 4K with a scale factor of 200%
> >>> on any *buntu version with 5.11 kernel so I have gfx software new
> enough
> >>> to support my 11th gen Intel based NUC.
> >>>
> >>> This seems to help 1080 content like mythtv since the TV in UHD
> improved
> >>> HD content.
> >>>
> >>> If I set my HDMI 2.0 switch to the NUC and boot it, my TV is rock solid
> >>> regardless of what video I play, mythtv, streaming, games, etc.
> >>>
> >>> If I leave the NUC on and switch to another HDMI source and later back
> >>> to the NUC I get the occasional screen blanking and loss of audio for
> >>> about 1-2 seconds. This repeats randomly.
> >>>
> >>> I can fix this by:
> >>>
> >>> 1. rebooting or
> >>>
> >>> 2. setting the screen to 1080p 100% scaling.
> >>>
> >>> This sound like that old problem where you had to capture the EDID in a
> >>> file and play with xorg.conf so the settings got reset with an HDMI
> >>> event like switching.
> >>>
> >>> I can't find that old discussion.  I have not had to do any such tricks
> >>> is a very long time.  This just started when I changed to 4K settings
> >>> instead of HD.  It's always been a 4K TV. I thought it might be
> hardware
> >>> but all the cables and switches are 4K at 60 HDMI 2.0 rated.
> >>>
> >>> At this point I just reboot each time I want to connect the PC to to
> the TV.
> >>>
> >>> Any ideas??
> >> You could get a better HDMI switch - I think there are ones that will
> >> remember the EDID data and emulate the presence of the TV on any ports
> >> where the real TV is not connected.  Full KVM switches seem to usually
> >> have that feature.  But good HDMI KVM switches are not cheap.
> >
> >The switch I picked was about $40 and worked great until I started
> >testing at 4K at 60. I tried using the second HDMI on the TV but had issues
> >with that, so I didn't spend a lot of time with it. Since I split the
> >output of the switch with a HDMI 2.0 digital audio extractor. I didn't
> >want to go that route.
> >
> >the switch I use is
> >
> >
> https://www.amazon.com/gp/product/B07MCS9PJD/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
> >
> >Jim A
>
> There is no sign on that page of EDID support, so it likely does not
> have it.  HDMI switches with EDID support normally tell you as it is
> an important feature, and justifies higher cost.
>
> I did an experiment. I plugged in my NUC PC directly to my HDMI2 TV port.
I could not see anything until I changed the HDMI UHD color setting to turn
OFF HDMI 2.0. At that point I could see the PC desktop, but it was only
4K at 30.  To get 4K at 60 I have to turn on HDMI 2.0 support.

So now I'm back on my HDMI 2.0 Switch and HDMI 2.0 support is turned on for
that HDMI1 port. The PC is set to 4K at 60 and the TV info shows 4K at 60. I also
have a Nividia Shield TV connected to the switch and it works at full 4K at 60.

While trying to write this email the screen has blanked out for a second
twice.

Rebooting seems to be my only choice.  However, I'm very curious why the PC
directly connected to the TV HDMI2 port can run 4K at 60 with the TV in HDMI
2.0 mode??

Since the EDID switches are expensive and so are newer UHD TV's, I'm stuff
for now.

Jim A
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