[rascas]

So I started over I installed the latest Buster on my RPi4 4GB (2019-9-26), setup the system to use rootfs from USB3 SATA drive to increase speed of system.

Then I installed kodi per the link you gave above.  After kodi and kodi-pvr-mythtv were installed I tried running them without rebooting.  The keyboard response time was seconds for each keystroke. After I rebooted that was fixed, but I still had audio/video sync issues like the hardware acceleration was not being used.

Logfile below:
logfile

The udev rules file is as below:
 
SUBSYSTEM=="drm", GROUP="video", MODE="0660"
SUBSYSTEM=="tty", KERNEL=="tty[0-9]*", GROUP="tty", MODE="0660"

Your problem now is different, you didn't set enough gpu memory, see the Guide that I posted above, it has a lot of information.

[jfabernathy]

your right I forgot the gpu memory split.  However, that along didn't fix the problem. Still have video audio sync issues.

for reference my /boot/config.txt has the following:

disable_overscan=1
# Enable audio (loads snd_bcm2835)
dtparam=audio=on

[pi4]
# Enable DRM VC4 V3D driver on top of the dispmanx display stack
dtoverlay=vc4-fkms-v3d
max_framebuffers=2

[all]
dtoverlay=vc4-fkms-v3d
gpu_mem=320
hdmi_enable_4kp60=1

[rascas]

Ok, so still back to the first problem.
Did you enabled "Sync playback to display" option in Kodi video settings ? And "Adjust display frame rate" or something similar ? If so try with both disabled.

Also notice that Kodi on RPi runs better if you limit the interface to 1080p, see first post of the guide again. There maybe some issues if you leave it at 4K.

[jfabernathy]

Ok, so still back to the first problem.
Did you enabled "Sync playback to display" option in Kodi video settings ? And "Adjust display frame rate" or something similar ? If so try with both disabled.

Also notice that Kodi on RPi runs better if you limit the interface to 1080p, see first post of the guide again. There maybe some issues if you leave it at 4K.

I did not sync playback or adjust display frame rate. I did select HDMI Pass Thru for audio though. When I try to force Kodi to use 1920x1080p it makes no difference on video audio sync but messes up the kodi display by sort of zooming the display.  Kodi icons are pushed to the edge of the screen and truncated.

minifaqiki (paste)

[rascas]

Try with audio passthrough disabled then. And in 1080p, check your overscan settings on the TV first and if not fixable, on the RPi.

[jfabernathy]

Try with audio passthrough disabled then. And in 1080p, check your overscan settings on the TV first and if not fixable, on the RPi.

I disabled passthrough and set to 1080p. no change on the lip sync issue. I'll worry about overscan after we fix this more serious problem.

[jfabernathy]

I did some digging into my hardware setup.  My 4K UHD TV has 2 HDMI connectors.  I have a Nvidia Shield TV plugged into one and it is running 3840 x 2160 x 60hz. The other HDMI is connected to my Denon receiver that only puts out 30hz when in 4K mode. This is not normally a problem since my Nvidia Shield TV is the only 4K content I have. When my Rpi 4B is connected to the Denon I set the screen resolution to 1080P 60hz and up to this point Mythtv only displays recorded TV in 1080i or 720P so no issues there.  However, Kodi on rpi 4 doesn't work in 4k or HD when set in the system settings. both have audio sync issues.

So I thought I try the newest LibreELEC that has RPi 4 support. That will not work for me long term as I need mythtv backend running under Raspbian buster.

I can get Kodi on LibreELEC working if I use Kodi system settings to change the resolution to 1080p and freq to 60hz from it's default of 4kx30hz. The recorded TV (mpeg2) plays as expected completely in sync.  Not sure how to translate that into Kodi 18.4 on Raspbian Buster.

[rascas]

Well I am out of ideas then...

In Libreelec, are you talking about the option "Limit GUI size" in system settings or what else ? Does Libreelec also have the audio sync problem if you don't activate/change that option ? I am asking this because, if that's what fixes the problem, I can add the same patch to next Raspbian Buster Kodi build.

[jfabernathy]

Well I am out of ideas then...

In Libreelec, are you talking about the option "Limit GUI size" in system settings or what else ? Does Libreelec also have the audio sync problem if you don't activate/change that option ? I am asking this because, if that's what fixes the problem, I can add the same patch to next Raspbian Buster Kodi build.

The only change I made to LibreELEC version of Kodi was to change the Resolution from 4k to 1920x1080p and the freq from 30hz to 60hz.  If I didn't do that change the videos were jumpy but the audio was in sync with the video.  Once I changed to 1920x1080x60hz, it worked like you would expect. Just like on RP3B+.  I could never get Kodi on RP3B+ with Raspbian to be a good as LibreELEC on RP3b+ but I didn't spend a lot of time on it as all my RP3B+ devices were setup only to be Kodi with kodi-pvr-mythtv frontends.  LibreELEC was fine for that.

My many mythtv backend is headless on a 8TB core i7, but I'm trying to build a portable combo FE/BE mythtv device to take with me. It would be nice to have Kodi on it but mythfrontend works okay as is, but not a flexible as Kodi.