Even if this is a false alert for 90% of titles, it's also a problem.
Why? I'll explain: When I ripped BTTF part I which has the Atmos track, there was no way to fix this. Apparently the only solution was to let all other tracks in the MKV file, including the DD 5.1 derived from Atmos. If I do that I don't see the audio dropout bug.
However BTTF part II I ripped twice and the first time (note: also has the same A/V SYNC ISSUE warning) I noticed a very quick freezing in a specific moment of the movie (less than 500 ms for sure). The 2nd time I didn't notice. The Atmos track is still there.
That doesn't mean:
- MAKEMKV isn't damaging the end result in any way;
Or
- The disc isn't flawed/defective, which may explain why MAKEMKV says A/V SYNC ISSUE. The disc could be messed somehow.
For BTTF part I thought this was a false alert, after reading posts from here.
Did you know how I discover this was not the case?
Not by watching almost 2 hours from the movie, and 120 minutes for each track, and noticing if there was something wrong.
I discovered there was something wrong only if the Atmos track was there in an unusual way:
- By splitting the 4K MKV file into 15200 MB parts, using MKVTOOLNIX, to put these splitted parts in Google Drive free accounts.
So I opened part 4 and right at the first seconds there was audio dropout. And there was image freezing lot longer than 0.5 second. In fact, SECONDS.
This bizarre bug affected the video as well, as if the Atmos was a virus damaging anything in its path.
If I hadn't opened the files I would never had spot any of this in the 1st place.
So, when we read things like that:
*********
Yes, ignore it. It's an informational message most of the time anyway. Unless you're dealing with Atmos... And it only means something if a track and location are present.
*********
We assume everything will be fine... until we check if MAKEMKV's warnings hold any water.
Also, from the looks of it this is not an Atmos bug:
Sat Dec 14, 2019 from here:
viewtopic.php?f=8&t=21079
Says:
*********
I've seen these issues come in with UHD rips as well in the last few days, and in all cases none of the rips have included an Atmos track. They've been DTS-HD, and the Blu-Rays I have tested have all been DTS. I'll be sure to test some Dolby back-ups today.
*********
So, to sum things up:
- All these discs can't be defective. What are the odds?
In my case all MAKEMKV use is done with the folders from 4K/BD already decrypted and stored in my SSD.
Logic then tells me this is MAKEMKV's fault, which is not doing what needs to do properly, perhaps due to some inconsistency in certain titles, which trigger these warnings and result in a few cases broken tracks that may or may not affect the video as well.
Unless this bug is fixed then we can never trust the MKV rips we get again.
****************
EDIT:
I just saw Mike has released a new MAKEMKV version:
**********
MakeMKV v1.15.4 (8.12.2020 )
Improved handling for discs with mastering errors
Many internal improvements and small bugfixes
Implemented seamless joining of TrueHD streams with overlapping frames based on Dominik Mydlil's idea
MakeMKV now recognizes and converts double-track Dolby Vision MKV files
Bug fixes:
Program could fail when processing TrueHD streams from MKV file
DTS core was not extracted from DTS-HD streams (1.15.0 regression)
**********
I am going to verify if it changes anything here, and let you know the results if not today, in the next days.
What I said earlier is that if we don't know if the file has been affected, it is difficult to analyze thoroughly. MAKEMKV just saying it has A/V SYNC ISSUES and us taking hours to really make sure these are not there is not practical. I am used to rip my discs and only later go back to the files.
