7.1 PCM No Audio

gillious · 28 July 2018 10:10

I have a Onkyo TX-NR686 AVR, I am unable to get any audio when my Vero 4K is sending 7.1 PCM. If I set number of speakers in Kodi to 5.1 then the audio is working. When set to 7.1 my AVR shows it is receiving a 7.1 PCM multi channel input but I hear nothing apart from a ‘thud’ sound when the audio stream is first started.

Using passthrough 7.1 works, however there are various UHD Movies from Disney that have audio dropout issues when using passthrough and I’d previously been playing these movies using PCM on my old AVR to avoid this issue.

Log: http://paste.osmc.tv/osolunozuk

The first time I play the movie The Greatest Showman with 7.1 PCM and there is no audio from my AVR.

The second time I play with 5.1 PCM and the audio works.

The third time I use 7.1 passthrough of Dolby Atmos and this works.

grahamh · 28 July 2018 10:12

Set the audio output to PCM Analog.

sam_nazarko · 28 July 2018 10:15

This will be fixed in the next update.

gillious · 28 July 2018 10:19

lol, that worked thanks… feel dumb for not trying that…

grahamh · 28 July 2018 10:26

Don’t feel dumb. It used not to matter (before we sorted out the channel mapping issues), and will not matter again after the next upgrade which includes a fix.

gillious · 28 July 2018 10:32

I guess related, do you guys have an idea on if you can fix the Dolby Atmos dropouts on several Disney UHD movies or is it something Kodi need to fix?

As per the end of Playback improvements for 4K HEVC UHD content - #77 by sam_nazarko thread you can see that the issue has been resolved for PC playback but still exists on the Vero and shield etc.

I don’t know much detail apart from people saying the Disney movies sometimes have very high bitrate that causes the audio to drop. It is always at exactly the same places per movie. Guardians of the Galaxy 2 only has a few, but Pirates of the Caribbean Dead Man’s Chest and Coco has loads of drops.

More details can be found at:

https://club.myce.com/t/atmos-audio-drop-outs-details-thread/399840/84

github.com/Nevcairiel/LAVFilters

TrueHD bitstreaming drop-outs on high bitrate Atmos streams

opened 01:07AM - 02 Jun 18 UTC

closed 06:10PM - 03 Jun 18 UTC

Nevcairiel

bug audio

TrueHD bitstreaming can cause audio to cut out briefly on high bitrate Atmos str…eams (as found on UHD Blu-rays). This is caused by the individual frames being too large for the current logic that builds the MAT frame for HDMI transmission. Unfortunately the exact workings of the MAT format are unknown. A few examples where this happens: > - “Pirates of the Caribbean - Dead Men Tell No Tales” - Max Bit rate is 11.9 Mb/s : eg drops out a couple of times between 17:45 and 19:00 minutes into the movie > - “Guardians of the Galaxy Vol II” - Max Bit rate is 11.3 Mb/s: eg drops out at 1:09:24 where TaserFace gets killed is one example. > - “Maze Runner: The Death Cure” - Max Bit rate is 12.1 Mb/s: eg Right at the beginning of the Main Title when the 20th Century clip is running. Drops outs so frequent that playback can actually stall.

https://forum.kodi.tv/showthread.php?tid=327153

Many Thanks

gillious · 30 July 2018 20:41

Just a heads up, might be expected but I’ve just updated to the latest test build and now passthrough of all audio is not working. On the plus side the 7.1 PCM works without having to select PCM Analog.

sam_nazarko · 30 July 2018 21:02

Can you confirm what commands you ran?
We’d hope this would be fixed now. Also try checking for updates once more.

Cheers

Sam

grahamh · 30 July 2018 21:07

Please post debug logs.

gillious · 30 July 2018 21:10

I’ve had http://apt.osmc.tv stretch-devel main in my sources.list since I’ve pretty much had the Vero 4K and I often just grab an update when prompted.

I’ve just forced an update again and it seems to be fine now. Also, pleased that DTS High Res audio is now working without doing odd stuff.

sam_nazarko · 30 July 2018 21:26

@grahamh: OP probably received the bodged Kodi patches.

Should all be fine now.

Thanks for confirming @gillious