[johnpgreenan]

Hi,

After auto refresh rate change, the audio (atmos, DTS etc) is not passing through, I think WASAPI is failing. If I switch off auto refresh rate it works fine.

This is Windows PC > LG TV.

Windows 11 23H2. Intel Core i3 12100 using Intel UHD Graphics 730. Kodi 21.1. TV is LG G465.

I also have a Samsung Q930d soundbar. When I go this route Windows PC > Soundbar > LG TV it works as expected, passthrough works just fine.

I have found references to this issue here:

https://www.reddit.com/r/kodi/comments/q...ith_atmos/

15490 (GH issue)

340358 (thread)

I tried the Delay after change of refresh rate of 5 seconds but this didn't help. I tried the disable / enable in the player audio settings as quick fix, reverts audio to multichannel only, so not really a fix and is still doesn't pass atmos etc.

LG TV audio is set to passthrough, I just don't understand why it works fine through the soundbar, but not direct to the tv. I wanted to try a Sonos soundbar which has no HDMI in, hence why I'm trying Windows > TV.

[johnpgreenan]

Log
apiyuhigob.kodi (paste)

[CrystalP]

Yes the problem comes from the refresh rate change. On your system the tming is just right to make audio come back just a bit late and make Kodi fall back to DirectSound, which doesn't passthrough high resolution formats afaik.
The delay after refresh rate change doesn't help as it only delays the start of the playback, not the attempt to reopen audio. But changing that would likely fix the issue.

[johnpgreenan]

Hi, thanks for the reply.

I think I understand. So you say if Kodi also delayed audio as well as refresh rate then this would work. Is this in scope for any new builds?

Any tips on troubleshooting where on my system the issue may lie? Drivers? HDMI Cable (I think mine is good, LG TV has 48gbps ports and this cable is capable, I tried a couple), TV?

I tried an EDID splitter box and this helped, Im also going to try display port to hdmi, but I would rather have it all working as intended with HDMI cable.

Thanks

[CrystalP]

I read the log again and see something different now.
15:11:11.823 enumeration of available audio devices, hdmi is not back yet > Kodi decides to fallback to default device (the spdif)
15:11:11.823 attempt to open default device, fails for TrueHD (not possible with spdif).
15:11:12.500 second attempt to open hdmi device (and for some reason AE forgot about the fallback to default device) - failure, hdmi is not back yet
15:11:12.624 Windows events received about device addition and change of default device
15:11:13.007 third attempt to open hdmi device. Succeeds, but device appears as "Device not found", probably because Kodi did not re-enumerate > hypothesis: maybe it's also missing other attributes needed by AE for passthrough to work.
Guess: a re-enumeration of available audio devices would cause a 4th attempt to open, this time with valid name and attributes and may fix the problem.

@jogal ideas, thoughts?
I didn't dig in the code, but maybe we could trigger a re-enumeration when an unknown device is opened because it's not a normal situation, or find out why the Windows events don't cause a re-enumeration.

----------

There is nothing wrong with your system, it's just that Kodi doesn't handle well that particular combination.

Anything that could have an impact on the timing of the mode change (some call this the handshake I think) could be a factor.
The brand/model of GPU, maybe even the driver/Windows versions, the brand/model of receiver/tv. A splitter / hdmi tweaking box may change the timing as well.

[johnpgreenan]

Thanks. I think you are correct about the timing. I have been trying an EDID based splitter and this works (although its not passing through TrueHD or DTS HD), also when I plug direct to soundbar it works as well (but this way, when I resume from sleep Kodi is in a minimised state and I have to force quit to start it up again)

My motherboard is HDMI 2.0 and TV is HDMI 2.1. I get it could be a combination of anything, could be the TV, if I changed motherboard to HDMI 2.1 that might fix it....but its all costly solutions to problem solve.

I had my old TV and LG B8 with HDMI 2.0 side by side with the G4, plugged my PC into each one respectively and the B8 had no issues, but the G4 did.

Oddly enough when I switch the display to 30Hz RGB 10bit TM SDR this issue goes away and it does the refresh and HDR change successfully, but then I'm limited to 30Hz because of HDMI 2.0 @ 10bit and I have 50/60fps media that doesnt play well at 30hz.

Here's 2 clips of it, first one at 8bit 60 where it fails, second at 10bit 30 where it works

60Hz RGB 8bit TM SDR

30Hz RGB 10bit TM SDR

[johnpgreenan]

Cant edit posts yet...........I decided to put Kodi on my laptop and connect to TV to see what would happen, and it was exactly the same as the HTPC.

I also set up MPC-BE to do refresh rate change and SDR to HDR switch and this also done the same as Kodi.

I guess the LG G4 and refresh switch / SDR to HDR in this particular order just don't get on well with a windows PC. Who knows if this is an HDMI issue with the TV that might be fixed with firmware updates (it is a 2024 TV) or if its just a "feature" of this TV.
How on earth I'm going to explain this to LG support and get them to understand is probably an impossible task.

[johnpgreenan]

Also noticed when HTPC to Soundbar to TV that when it does SDR to HDR switch, it changes from 60hz 8bit to 24hz 10bit. This made me wonder about the fact that I because cant use the mode 60hz 10bit (hdmi 2.0), that when it tries to switch to HDR it momentarily tries 60Hz 10bit and this is what fails as it cant display it?

Pre refresh change SDR to HDR


Post Refresh change and now in HDR

[CrystalP]

Quoting myself

There is nothing wrong with your system, it's just that Kodi doesn't handle well that particular combination.

[johnpgreenan]

Thanks, appreciate it.

Its definitely the change from 8 bpc to 10 bpc I think. I got a HDMI 2.1 EDID Splitter tonight, and it works, the only difference being is that it keeps the display at 8 bpc, you can see that when kodi switches windows to HDR it doesn't go to 10 bpc. I don't think I notice anything different in the quality.