Issue with the RPi3 and Dolby Atmos Movies

  • 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 and I have no center channel voices. The only fix is to stop or reboot and try again. It doesn’t happen all the time but enough to be annoying.

    Setup: RPi3, LibreELEC 8.0.1 @ 5.1, Pioneer VSX-824-K.

  • 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.

  • 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.

  • 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 - Refresh set to "ON START / STOP": 7 out of 10 tests failed (no center channel)

    * Test 2 - Refresh set to "OFF": 0 out of 10 tests failed (center channel present)

    * Test 3 - Refresh set to "ON START / STOP": 8 out of 10 tests failed (no center channel)

    * Test 4 - Refresh set to "OFF": 0 out of 10 tests failed (center channel present)

    * Test 5 - Refresh set to "ON START / STOP": 5 out of 10 tests failed (no center channel)

  • Disabling OMXPLAYER and using MMAL fixes the problem. 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. There is an issue with OMXPLAYER.

  • Sorry, the forums had a bug reporting section stating to report them here, including video playback issues. Can you clarify the difference between a KODI bug and a LibreELEC bug? This may need to be noted in the How To notice.

  • Sorry, the forums had a bug reporting section stating to report them here, including video playback issues. Can you clarify the difference between a KODI bug and a LibreELEC bug? This may need to be noted in the How To notice.

    Any issues that a present when using Kodi and can be seen in the Kodi debug log can be considered a Kodi bug.

    Anything related to the OS itself (network, boot, shutdown, updating, backup, restore, etc) is a LibreELEC bug.

  • Disabling OMXPLAYER and using MMAL fixes the problem. 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. There is an issue with OMXPLAYER.

    OMX player is legacy and should not be used anymore unless explicitly needed.