Kodi Community Forum

I have been using my ShieldTV and Kodi for playback of UHD BD rips I have created.  I am finding two specific titles have repeatable Atmos audio dropouts during playback.  Guardians of the Galaxy V2 and Pirates of the Caribbean: Dead Men Tell No Tales both exhibit this issue.  I have verified the rips through various methods and am convinced it is neither the disc not rip at this point.  We have an ongoing discussion around the topic over at MyCE and I also made a post over at the Geforce forums.  So far, the best answer we have come up with was from nevcairel over at Doom9 where he states it is an issue with the unknowns around the Dolby MAT specification itself.  Those two specific titles have a TrueHD max bitrate exceeding 11mbps which is considerably higher than what we have seen on normal BD discs.  With UHD BD peak bitrate able to exceed 100mbps could there be an issue with the current passthrough method in Kodi as I am sure it is following the standard IEC/AndroidTV convention?

Link to MyCE discussion for those interested: https://club.myce.com/t/atmos-audio-drop...ead/399840

I was able to reproduce this with Pirates of the Caribbean : Dead Men Tell No Tales. I didn't have any long dropout. Most of them were only fraction of a second and didn't show up on my AVR's (Denon X6200) display. I tested it on the Shield,  Minix U9H, Zidoo X9S and Power DVD 17 (Kaby Lake Core i5 on Asrock Z270 iTX). The was no dropout on PowerDVD 17 or Zidoo X9S. This suggests that the problem is likely with the IEC 61937 packer that is being used in Kodi, FFmpeg etc. They are all based on the code written by Bartlomiej, Anssi & Carl in 2009/10. PowerDVD 17 is using Windows Dolby MAT 2.0 and Zidoo is using Realtek's packer. I don't know whether this has anything to do with the constant rate frame packing. There was a patch back in 2012 to tackle buffer overrruns of Dolby TrueHD audio. @fritsch may be able to look into it this if we provide a sample.

That was pretty much the reply I expected.  I had already guessed it was a problem within FFMPEG and the IEC packing method.  Thank you for confirming.  I guess I need to put a ticket in over FFMPEG...

I've seen this too on Guardians of the Galaxy 2 using the Shield. @wesk05  - thanks for testing this on multiple devices. It is good to know that this is not an issue on the Zidoo. I'm very interested in the soon to be released Dune HD Pro 4k. It will be using the RTD1295 so it is likely that it shouldn't have this issue either.

If anyone else wants to test this on their system, here is a 1 min sample from the movie. Towards the end of the clip, you will hear 2-3 interruptions/noise.

https://mega.nz/#!oJVzDDiZ

Decryption key: !VZSnDiayjtDl2RDCzNOV-kw6R3MV8bMwX3YXLMuXamg

A debug log with Kodi 18 Alpha (20180115-18f76ab) on nVIDIA Shield: https://paste.ee/p/gdQ04

Just resurrecting this to say that @nevcairiel updated LAV filters (in the lastest nightly) to address the audio dropouts on PC.  I have tested all of the suspect discs and they now play dropout free through MPC-HC and LAV/madVR.  I hope these changes can find their way into Kodi for Android.

(2018-01-23, 19:31)wesk05 Wrote: [ -> ]If anyone else wants to test this on their system, here is a 1 min sample from the movie. Towards the end of the clip, you will hear 2-3 interruptions/noise.

https://mega.nz/#!oJVzDDiZ

Decryption key: !VZSnDiayjtDl2RDCzNOV-kw6R3MV8bMwX3YXLMuXamg

A debug log with Kodi 18 Alpha (20180115-18f76ab) on nVIDIA Shield: https://paste.ee/p/gdQ04

I am downloading the file to try it on my Shield TV, I will report back...

EDIT:
I can confirm the audio dropout.

I've been looking at this.  I've had some success with allowing each 2560-byte chunk to overflow into the next one, but there are still some problem clips that LAVfilters seems to be able to handle that I can't with hacks to AEBitstreamPacker.

Is @fritsch  or anyone else doing any work on this?  If not, I will carry on.  Has anyone got any details (Dolby specs) of what is the proper way to deal with these overflows?

Please carry on! Thx much.

Nvidia says they have fixed this issue in the next release for the Shield. I'm not quite sure what they've done, but would Kodi still need to implement a fix if passthrough is used?
https://forums.geforce.com/default/topic...9/#5902629

(2018-10-28, 19:31)movd Wrote: [ -> ]Nvidia says they have fixed this issue in the next release for the Shield. I'm not quite sure what they've done, but would Kodi still need to implement a fix if passthrough is used?
https://forums.geforce.com/default/topic...9/#5902629

 According to nvidia kodi will need the fix too

We can see if they fixed it, by "just4fun" using their IEC packer after the release to verify. Just ping me after you have that version.

Btw. graham-h is working on that fix to my knowledge and anssih might help out here, too

@graham-h  do you have an update yet?

Sorry, I didn't get a ping from your question, or missed it.  I emailed Anssi at the address on his commits but didn't get a response.

Then other things got in the way.

No hurry :-) Other also had holidays - and could have helped implementing it. Happy new year!

Anyone have an update on this? I experienced this a few nights ago on an ATMOS track with the Nvidia Shield using Plex.  I tried Kodi as well and same issue.