www.makemkv.com

Hello all,
I had the same problem "A/V synchronization issue" and the UHD/4K disc (yes, this was not 1080p Blu-ray) also had Dolby Atmos track.

And unfortunately, contrary to what other users were saying before, this was not an innocuous warning. The generated file HAD audio dropout and even skipped frames at a specific scene from the movie.

I made a few posts in the Doom9 online board, detailing how MAKEMKV created a problematic file. At first I thought this was MKVTOOLNIX fault, however it WASN'T.

The first post can be read here:
https://forum.doom9.org/showthread.php? ... ost1927899

I strongly advise MAKEMKV developers to read it, then again I believe they are already well aware of this, since this was not the only title affected.

I have not checked other 4Ks I saved with MAKEMKV's help, that perhaps also showed the same warning, and I must say if this problem (that happened now) is repeated in all of them, in a few moments of the movie that we need to watch fully to spot, then this is veeeeeeeeeeeeeeeeeeeeeeeeeeery bad news.

I hope, if this is indeed a bug in MAKEMKV, that you can fix ASAP. I am not seeing how the disc can be in any way defective. When I play the same passage from the BDMV/STREAM folder (mts) there are no signs of audio dropout of skipped frames.

Errors only ensue after MAKEMKV handles these discs.

Oh, and the fact my disc also had Dolby Atmos is a clear indication this track may be in all affected titles.

You need to a serious investigation.

I did some digging and decided to save the original UHD/4K again as MKV.

I think I am onto something important. Bear with me...

First of all, the main feature, which is the movie (73 GB size, more or less...) has Dolby Atmos to be selected as 1st track, then in the box below ENGLISH DD 5.1, then DD 5.1 spanish, DD 5.1 french, and 2 more audio tracks, which I confirmed to be audio commentaries.



This is title #2, and MAKEMKV says it has read from 00040.mpls.

There's another duplicate of the movie in that screen, which says it's reading from 00294.m2ts. Same tracks.

About this title #2, I had this problem after selecting:

- Dolby Atmos
- DD 5.1 English
- The 2 audio commentaries
- English subtitles

So I went back and only saved the video, and nothing else.

No problem.

I went back again and saved the video and...

- Dolby Atmos
- DD 5.1 English

No problem. NO WARNINGS! And this goes for title #2 and the duplicate.

However, once I selected the 4 audio tracks + the subtitle, the problem happened AGAIN.

A/V synch issues.

This is veeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeery strange, since I said Dolby Atmos was probably the culprit. It turns out the A/V synch issue only happens with further tracks being selected.

*****************
More tests:

>>>>>>> What if we select the first two audio tracks (Atmos and 5.1 english) and the english subtitles? (TITLE #2)

A/V synch issues. Now we have to look what happens if we select the other 2 audio tracks.

>>>>>>> What if we select only the first three audio tracks? (TITLE #2)

- Dolby Atmos
- DD 5.1 English
- 1st audio commentary

Like this:



Result: No problem.

**********
FINAL TEST: selecting ALL audio tracks, and leaving the subtitle out.

No issues.

Proof: LINK

***********



So the fact I selected that english subtitle was what triggered this issue. Did you see that? Not a single warning after I selected:

- Dolby Atmos
- DD 5.1 English
- Audio commentary #1
- Audio commentary #2

What do you have to say now?

Oh, and I'll check again if the issue reported in Doom9 is still there.

I can disprove your claim because I had the same issue when ripping the movie "Onward" (UHD) and not selecting any subtitles whatsoever. The issue still occurred and one of those sync issues caused an audible pop. Of course it could be different for each movie, but at least in my case with that movie it was definitely not caused by the selection of a subtitle track.

Anyway, Mike (the MakeMKV dev) is aware of this and working on a solution.

OK, I did a few more tests and this is what I discovered (sorry for the delay):

- Even though MakeMKV doesn't say A/V sync issue if we leave the english subtitle out, the problem is still there. So this was a false alert, when MakeMKV should have said that for the rest, not for the subtitle.

How so? I'll explain.

In my 1st post from this thread I mentioned a Doom9 message in which I tell the movie "breaks" if I split into 5 parts and there are audio dropouts, freezing... and even the single file not splitted had audio dropout.

Then I decided to save everything again with MAKEMKV's help, as MKV.

********
My final conclusion: indeed this is a bug created by MAKEMKV and the A/V sync issue is exclusive if we put the Dolby Atmos track inside the Matroska.
********

I tried to split the file again into 5 parts, each one with 15200 Megabytes.

The problematic scene showed the exact same issues mentioned in Doom9. And the issue (video freezing, muting...) happened even though there are several other tracks there.

However (attention here):

- If I split the huge 73 GB file generated by MAKEMKV into 5 parts;
- And only leave the Dolby Atmos track out.... and all the rest there, including subtitles...

Then the file will not freeze, have audio dropout or display any odd behaviour.

That indicates the video (and other tracks) were not affected in any way.

But if we put the Dolby Atmos track INSIDE THE MATROSKA, then that Matroska created from the UHD/4K disc...

Will go berserk. At least for this movie, and especially if you use MKVToolnix and split.

One important thing to note is that MKVToolnix doesn't create a problem, it only makes clearer for us.

So this is not a bug from this software, it's only exposing what's defective in the MAKEMKV's created Matroska file...

It's possible the huge 73 GB I created also has audio dropouts because the Atmos track is there, I am just not catching the exact moment the issue appears.

So the idea this MAKEMKV bug is directly related to any title having a DOLBY ATMOS track was indeed correct.

I even tried to do these tests with the Dolby Digital 5.1 english track that MakeMKV creates based on this Atmos track.

The bug also didn't happen. This indicates anything else in the UHD/4K disc is 100% fine, except when we put the Atmos track there.

Since this is happening I'll leave this track outside my file and only put back there once someone fixes whatever is going on here.

One thing's for sure: it's very, veeeeeeery unlikely this is a problem with the original disc.

*******
More details from the Atmos track:

Audio #1
ID : 2
ID in the original source medi : 4352 (0x1100)
Format : MLP FBA 16-ch
Format/Info : Meridian Lossless Packing FBA with 16-channel presentation
Commercial name : Dolby TrueHD with Dolby Atmos
Codec ID : A_TRUEHD
Duration : 1 h 56 min
Bit rate mode : Variable
Bit rate : 4 213 kb/s
Maximum bit rate : 7 626 kb/s
Channel(s) : 8 channels
Channel layout : L R C LFE Ls Rs Lb Rb
Sampling rate : 48.0 kHz
Frame rate : 1 200.000 FPS (40 SPF)
Compression mode : Lossless
Stream size : 3.41 GiB (5%)
Title : Dolby Atmos
Language : English
Default : Yes
Forced : No
Original source medium : Blu-ray
Number of dynamic objects : 11
Bed channel count : 1 channel
Bed channel configuration : LFE

Legenista, did you make sure to email support @ mkv.com as well? You piggy backed an older thread so this might get lost.

Krawk wrote: Tue Nov 10, 2020 12:45 am Legenista, did you make sure to email support @ mkv.com as well? You piggy backed an older thread so this might get lost.

No, what's the email address for support? I couldn't find anywhere and so far no way of reporting bugs. I thought the admins were reading all threads and taking notes.

I could reiterate to them all I said before, however it would be better if they read all my posts in this thread and visited that Doom9 link.

This problem is either exclusive to the handling of the Dolby Atmos track, causing A/V sync issue (audio dropout, video freezing...) or some other problem with these UHD/4K discs besides them being defective (very unlikely).

What's worse about this problem is that if I had selected only certain audio/subtitle tracks then this warning would never had been issued by MakeMKV and be noticed at first by me, and the problem would still be there. You saw this had nothing to do with selecting the english subtitle, but MakeMKV only told me about A/V sync issue after that.

This is a bug that somehow creates a problem with the Matroska when MakeMKV handles these UHD discs. I believe that removing the Atmos track solved this for me, at least for this title.

VarHD wrote: Mon Nov 09, 2020 8:49 pm Anyway, Mike (the MakeMKV dev) is aware of this and working on a solution.

This is (hopefully) to be fixed in 1.15.4 whic should be released soon. There is a test version with a fix available, please PM me for details...

Great news about the fix! In this thread users reported problems with this set, too:
viewtopic.php?f=12&t=23464

Just a quick more details about this bug that I discovered only today:

- BTTF Part II also had the same issue (I was talking about part I before). But for the first time I noticed something odd: at 42 min the video (note: MKV with Atmos inside, created by MakeMKV) freezes for less than a second, and continues. It's in the scene Marty is talking with Strickland from the alternate 1985. I believe the video freezes for 250 ms, more or less.

Then I tried removing the Atmos from the MKV, to see how it would behave. No luck. It stayed the same. So this MKV lossless rip from the disc has been affected in the video.

Then I tried to do a second rip from BTTF part II. However this time the Atmos track WAS NOT selected. Only the rest. Same warning about A/V sync issue, but... no freezing in the same area (42 minutes and a few seconds).

Conclusion: the mere fact I selected the Atmos track made not only this track spoiled, also damaged the video itself!

*******
I also checked MediaINFO for more details about the two files. The one broken with Atmos and the other fixed without the Atmos track.

They are both the same, but... I noticed a very interesting difference:

AFFECTED WITH ATMOS TRACK:

**********
Format : HEVC
Format/Info : High Efficiency Video Coding
Format profile : Main 10@L5.1@High
HDR format : Dolby Vision, Version 1.0, dvhe.07.06, BL+EL+RPU, Blu-ray compatible / SMPTE ST 2094 App 4, Version 1, HDR10+ Profile B compatible
Codec ID : V_MPEGH/ISO/HEVC
Duration : 1 h 48 min
Bit rate : 84.6 Mb/s
Width : 3 840 pixels
Height : 2 160 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 23.976 (23976/1000) FPS
Original frame rate : 23.976 (24000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0 (Type 2)
Bit depth : 10 bits
Bits/(Pixel*Frame) : 0.425
Stream size : 63.8 GiB (92%)
**********

And the fixed:

********
Video
ID : 1
ID in the original source medi : 4113 (0x1011)
Format : HEVC
Format/Info : High Efficiency Video Coding
Format profile : Main 10@L5.1@High
HDR format : Dolby Vision, Version 1.0, dvhe.07.06, BL+EL+RPU, Blu-ray compatible / SMPTE ST 2094 App 4, Version 1, HDR10+ Profile B compatible
Codec ID : V_MPEGH/ISO/HEVC
Duration : 1 h 48 min
Bit rate : 84.6 Mb/s
Width : 3 840 pixels
Height : 2 160 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 23.976 (24000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0 (Type 2)
Bit depth : 10 bits
Bits/(Pixel*Frame) : 0.425
Stream size : 63.8 GiB (92%)
********

The framerate. Compare both infos above... does that account for the A/V sync issues?

Legenista wrote: Thu Nov 12, 2020 8:38 pm They are both the same, but... I noticed a very interesting difference:

Please do and send me both text files (please compress). Note the capital -C . Thanks!

mike admin wrote: Thu Nov 12, 2020 9:56 pm

Legenista wrote: Thu Nov 12, 2020 8:38 pm They are both the same, but... I noticed a very interesting difference:

Please do

Code: Select all

mkvinfo -C xxx.mkv > xxx.txt

and send me both text files (please compress). Note the capital -C . Thanks!

Is this a command to be run from the Windows prompt? If so, from where (what folder)? What files are you referring to?

Note: just typing (in the DOS prompt) mkvinfo and hitting enter says "this is not a recognized software", so it needs to be run from the folder where the mkvinfo.exe is located.

Legenista wrote: Fri Nov 13, 2020 1:14 pm

mike admin wrote: Thu Nov 12, 2020 9:56 pm Please do

Code: Select all

mkvinfo -C xxx.mkv > xxx.txt

Is this a command to be run from the Windows prompt? If so, from where (what folder)? What files are you referring to?

This is a tool form mkvtoolnix which you already have. Should be alongside with mkvmerge . Unlike mkvmerge that has a gui version, this is console only.

First, if we run from there we need to use Admin privilege, otherwise the access is denied.

Running from there, only one xxx.txt file is created.

And inside such file:

(MKVInfo) Error: Couldn't open source file xxx.mkv (open file error).

Do you need me to have a specific file in the MKVtoolnix folder (with that name: XXX.mkv), or a file already opened in the GUI while I do this?

I think Mike is asking for the output from the command for each of the MKV files you've made; the one that works and the one with the error. This way he'll be able to compare them.

The 'xxx.mkv' in his example command is the place where you substitute the name of MKV file you created. Similarly, substitute a logical name for the 'xxx.txt' that the output is captured into.

dcoke22 wrote: Sat Nov 14, 2020 12:34 am I think Mike is asking for the output from the command for each of the MKV files you've made; the one that works and the one with the error. This way he'll be able to compare them.

The 'xxx.mkv' in his example command is the place where you substitute the name of MKV file you created. Similarly, substitute a logical name for the 'xxx.txt' that the output is captured into.

Right, but listen to this:

- First of all, the movie mentioned (BTTF Part II) is UHD/4K (and before I was talking about part 1).
- The UHD/4K is already decrypted and all folders are in my SSD drive. I mean BDMV/STREAM and all others.
- Then I told MAKEMKV to open this local folder, and save as MKV.

Option A: if I select the Dolby Atmos track (with all others, or a few others), then we will have a broken file.

Audio dropout, freezing in a specific moment of the movie and then continuing (for 250 ms or 500 ms, more or less)... the usual abnormalities (that you may or may not spot) because MAKEMKV says "A/V SYNC ISSUES" at the end.

Option B: if I do not select the Atmos track, the file is generated by MAKEMKV without the same issue, because at this same specific moment of the movie there will be no freezing.

So what mike is asking me makes no sense, because there was no MKVTOOLNIX interference here. I only edited LATER and whatever edit I made had no bearing in fixing or not.

The point is: A/V SYNC ISSUE entails a bug related to the Atmos track that is also damaging the video itself.

It's like the Atmos track is a virus that is also corrupting the video. That's why MKVTOOLNIX later showed this bug more clearly for me, but MKVTOOLNIX didn't make any difference in what we are discussing here.

At first I thought this was MKVTOOLNIX fault, but it turns out this is 100% MAKEMKV's doing.

Also, it's very strange that a few users reported problems with the Back to the Future boxset, and said things like:

Important: these are posts from Blu-ray dotcom, and these people were not using any software, they tried playing the discs from their players (and were not using a PC either)

**************
*****
my back to the future 1 disc goes all pixeled at around 40 min any one else have this?
*****

Lysander91 replied: I had the same issue at about 48 minutes, but I cleaned the disc and it worked the second go. Disc looked spotless beforehand, so I'm crossing my fingers that it was just a spec of dust.

User nvadr also posted: Back to the Future Part II 4k disc there is some serious video glitching at 43:35 which continues until 47:09 where my UDP-203 player freezes up.

Bijouman replied: Your disc likely has a pressing defect where some pits are unreadable (the layers may be touching each other in one spot or another). Request a replacement from Universal Pictures Home Entertainment.

User Indiana Jones said: Many people have experienced issues but by all accounts its not a faulty disc issue so there won't be a replacement scheme.
**************

Also in the MAKEMKV forum an user said:

*******
A lot of people have had issues with this set.
Most people report that an extreme cleaning the of discs has resolved their issues.
Some people have had success turning the speed control off/down in the registry, although if you've never set this in the past it wont be causing an issue.
Some people have had success removing and re-applying the power to the drive whilst the computer is turned on and the disc loaded.
I had success trying a different firmware (WH16NS60 1.02) on my drive.
********

At first you would think: well, this must be UNIVERSAL PICTURES fault, not MAKEMKV's.

That can't be true, because A/V SYNC ISSUE is a defect (a bug) in MAKEMKV that existed BEFORE the BTTF UHD boxset was released.

And it was happening with OTHER movies:

December 2019:

- 1st post talks about "Once Upon a Time... in Hollywood" blu-ray disc using MAkemkv 1.14.7

Then this other post talks about this bug affecting more titles:
viewtopic.php?p=82326#p82326

However he doesn't mention the Atmos track.

His message:

*****
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.
*****

And the thread goes on.

The difference here, when it comes to BTTF (1 and 2 so far, haven't checked part 3) is that the A/V sync issue error doesn't say anything else, like:

*****
AV sync issue in stream 1 at 0:23:51.179 with duration of 0.375ms : encountered overlapping frame, audio skew is +1.083ms
*****

It's just A/V sync issue and that's it.