Black screen while changing TV channel in 4K mode

#1

Hello. I’ve installed latest coreelec (clean install) and also I’m using tvheadend client. Previously I’ve used libreelec 8.2.5. I’ve configured coreelec same way as libreelec was and now I’m having strange problems:

  • Reboot coreelec (for clean test)
  • Start playing any channel
  • Change channel without stopping current.

This leads to black screen - no more GUI or video. Gui will appear if I will make two clicks on OK (this leads to stop playing channel). After that I can play another one channel. This behaviour is only when using 3840x2160 screen mode - no problems with 1920x1080 mode. First I though it cause of resolution+refresh rate, but kodi uses same mod for this kind of channels and it just work fine:

cur_VIC: 96
VIC: 96 3840x2160p50hz
Colour depth: 8-bit
Colourspace: YUV444
Colour range: limited
EOTF: SDR
YCC colour range: limited
PLL clock: 0xc800027b, Vid clock div 0x000a339c
audio config: on
3D config: off

Attached log from dispinfo.sh: http://ix.io/1Aox

Also attached kodi log: http://ix.io/1Aoz
On 10:27:29.285 I’m starting playing channel.
On 10:27:41.030 I’m trying to start playing another channel (and got black screen).
On 10:27:53.614 I’m stopping playback and from now I can see GUI again.

#2

Try the test build posted in this thread, [BUG] Receiver is not accepting 10bit signal after latest update

#3

Thank. I’ve tried latest build, but it surely not related to resolution/refresh/hdr mode.
It seems that this bug is available only when coreelec (same with libreelec 9) started with 3840x2160 resolution with hw video acceleration. This means that there is no problems if coreelec was started either with hw acceleratin turned off or with 1920x1080 resolution. After start I can switch on acceleration and 4k mode and have no problems :frowning:

#4

Do not use higher than 1920 X 1080P for your GUI resolution.
System Settings Display Resolution.

Player settings / Videos Adjust Display Refresh on start stop enabled should solve your issue.

#5

Thanks. I’ve already found ‘Recommended Kodi Settings’ and now I understand why 1920x1080 is recommened for GUI. Anyway this looks like a bug, cause it was all OK when using libreelec 8.2.5 with such settings. Enabling 1920x1080 for GUI leads to another problem for me. I have two Samsung TV’s and 1920x1080 is not problem for them, but my main TV LG OLED. It stretches picture outside of screen in this resolution for unknown reason. I’ve checked all settings in TV (using ‘original size’ now), but it does not stretch only in 3840x2160 mode :frowning:

#6

You need to go to the picture settings on your LG and set Aspect Ratio to Just Scan.

#7

Thanks a lot! Now I have really good setup. I had to go to LG settings and set Format -> Original Size -> ON (instead of auto). The only missing thing is dual audio now :slight_smile: