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MidnightWatcher · (This post was last modified: 2017-09-06, 17:40 by MidnightWatcher.)

Hi all, I'm wondering if anyone has experienced this issue and knows of a fix. I don't believe this happened to me with KODI 16 even once, but with KODI 17 I'm noticing that when I go to watch a movie with the Dolby TrueHD Atmos track the speakers are sometimes mapped incorrectly. For example, the rear surrounds are coming out of the front speakers [Edit: After further testing I'm not entirely sure if that's the case. The problem may only be with the center channel] and I have no center channel voices. The only fix is to stop/restart or reboot and try again. It doesn’t happen all the time but enough to be annoying.

Setup: RPi3, LibreELEC 8.0.x @ 5.1, Pioneer VSX-824-K.

Edit: Title changed. The issue appears to be with OMXPLAYER and enabling the "Adjust Display Refresh Rate" setting. See below.

**popcornmix** · 2017-09-03, 14:00

Are you connected to Pioneer through HDMI?
Is passthough disabled? What is number of channels set to?
Or is passthrough enabled with AC3 transcode enabled?

Do you get the same behaviour (with same audio settings) on Zotac?

MidnightWatcher · (This post was last modified: 2017-09-03, 18:36 by MidnightWatcher.)

(2017-09-03, 14:00)popcornmix Wrote: Are you connected to Pioneer through HDMI?
Is passthough disabled? What is number of channels set to?
Or is passthrough enabled with AC3 transcode enabled?

Do you get the same behaviour (with same audio settings) on Zotac?

Update: It seems that enabling "Stereo upmix" in the Audio and Subtitle Settings fixes the problem. I've tested 7 different TrueHD 7.1 Atmos films and they've played without issue, so far.

Connected via HDMI, KODI set to 5.1. The same behavior was exhibited with passthrough on and off. I haven't tried the Zotac on the 5.1 setup.

MidnightWatcher · (This post was last modified: 2017-09-05, 07:59 by MidnightWatcher.)

Update: Looks like that didn't solve it. After viewing a few trailers and bumpers with CinemaVision, the center channel for the main feature (Mission Impossible: Rogue Nation) was silent/missing. When I disabled "Stereo Upmix" while the movie was playing everything suddenly played as normal.

Edit: Refresh syncing disabled by a CinemaVision action file prior to the movie trailers and then enabled just before the main feature is set to begin. Cf. Post 6.

MidnightWatcher · (This post was last modified: 2017-09-04, 05:41 by MidnightWatcher.)

Update: With passthrough disabled it has now happened to the DTS-HD Master Audio 5.1 track on War of the Worlds. No center channel. Once again, enabling or disabling "Stereo upmix" in the Audio and Subtitle Settings fixes the problem ... until it happens again.

MidnightWatcher · (This post was last modified: 2017-09-05, 21:26 by MidnightWatcher.)

I think I may have found a clue. I noticed that if "Adjust Display Refresh Rate" is set to "OFF" then the issue appears to go away. When set to "ON START / STOP" the issue returns. I've run the following set of four tests using films encoded with a TrueHD 7.1 Atmos track. The 5th test was with films encoded with DTS-HD 7.1. Audio settings have been reset back to default, number of channels set to 5.1:

* Test 1 - Atmos - Refresh set to "ON START / STOP": 7 out of 10 tests failed (no center channel)
* Test 2 - Atmos - Refresh set to "OFF": 0 out of 10 tests failed (center channel present)
* Test 3 - Atmos - Refresh set to "ON START / STOP": 8 out of 10 tests failed (no center channel)
* Test 4 - Atmos - Refresh set to "OFF": 0 out of 10 tests failed (center channel present)
* Test 5 - DTS-HD - Refresh set to "ON START / STOP": 5 out of 10 tests failed (no center channel)

**popcornmix** · 2017-09-05, 14:10

When you have no centre channel can you try power cycling receiver?
Also try unplugging and replugging the HDMI cable from Pi to receiver.
Does either of these cause centre channel to return?

MidnightWatcher · (This post was last modified: 2017-09-05, 22:26 by MidnightWatcher.)

I'll give that a try tonight, though I suspect the issue will remain. I did some googling and saw that this exact bug was also reported over on the OSMC forums (link below). I'll try the recommended setting there to see if it helps (using MMAL instead of OMXPLAYER). If that works, looks like the problem is with OMXPLAYER not wanting to play nice when Adjust Display Refresh Rate is enabled.

https://discourse.osmc.tv/t/audio-downmi...-v17/22323

MidnightWatcher · (This post was last modified: 2017-09-06, 03:58 by MidnightWatcher.)

Unplugging the cable and power cycling the receiver had no effect, but disabling OMXPLAYER and using MMAL works fine. I tested 10 Dolby TrueHD 7.1 and DTS-HD 7.1 movies with "Adjust Display Refresh Rate" set to "ON START / STOP" and they all played without issue when MMAL was used.