Chapter skip broken since March 2022 update (only mkvs with Atmos/DTS-X audio affected)

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23

While there was a confirmed chapter-skip bug for TrueHD audio when output to PCM/AC3 in 19.x, I’ve found this to be fixed in 20.x. I just tried very hard to break chapter/bookmark skipping for DTS:X and Atmos and failed to do so. I tried passthrough, full channel PCM, 2.0 PCM downmix and AC-3 conversion. Can you name a title that is causing problems? I might have it in my library.

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Hi guys, I did some more tests today and want to share the (weird) results:

  1. Not all mkvs with Atmos audiotrack do show the issue, just about 50%. However, there is no systematic pattern regarding the makemkv version that was used - some mkvs ripped with same version are ok, others are not (versions tested: 1.12.2 - 1.16.7)
  2. When issue shows, only specific chapters are affected, sometimes just 1, sometimes up to 4
  3. When you skip to these problematic chapters, video freezes, Time counter resets to 0:00 but when you quickly skip to next chapter again on the remote, it will resume playback on that next chapter.
  4. If the mkv contains both, Atmos track and non-Atmos track, e.g. DTS-HD or AC3, when switching to this non-Atmos audio track, there is no issue with chapter skip!
  5. When I switch off pass-through in Kodi audio settings, the issue does no more show either even on Atmos audio track!
  6. Now it becomes really weird: Same mkv file played either via SMB or from USB stick shows the issue in different characteristics - 3 chapters broken when played via SMB, just 2 out of the 3 when played from USB stick
  7. Seems the issue is no more present for mkv with DTS-X - however, not sure that I tried the same mkv a couple of month ago

Examples showing the issue: Roger Waters US+Them (chapters 4,7,8,10), A Quiet Place 1 (3,12,15)

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Are these videos ripped by yourself or are they remuxes?

This is why we really need a sample.

Also are you skipping frequently, or occasionally? I.e. are you trying to cycle through chapters very fast?

Sam

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All direct output of makemkv rips. Issue shows when cycling through chapters sequentially and also when skipping to the chapters via Bookmark. Doesn’t matter how fast I am cycling. For both variants, same chapters are affected.

Regarding sample: Wondering if this will work - I would expect that a clip of original video won’t show the issue. Do you have a recommendation how to prepare a sample?

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Just a trimmed / shorter clip would do. The smaller the clip, the better.

Sam

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So a few seconds before and after a chapter position that shows the issue? Which tool to use? Avidemux? I assume I have to avoid any remuxing? What about the chapter info? I guess it will be lost in the short clip?

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Mkvtoolnix?

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@sam_nazarko ok, I’ve created a 20sec clip with mkvtoolnix - where can I upload it to. I read it should be possible from within “my OSMC account” - I can create a ticket in there but will it let me upload a file after creation? Please advise. Thanks!

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You can upload it to a platform like Dropbox

32

ok, done, I sent you a private message with the details.
Thanks!

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@sam_nazarko Hi Sam, did you have a chance to look at the clip I sent you via private message? If yes, was it of any help to narrow down the issue? Thanks!

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Sorry - I can’t receive files via PM. It’s important to share with the whole team so it can be tested properly.

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@frank.lautenbach If you don’t have any other way to upload a clip, then using WeTransfer.com works quite well. (So long as you don’t go over the 2GB limit).