Remuxing Results in MKV Audio-Video Sync Problem

[gonwk]

Hi folks,

Here is what I am doing and getting MKV Audio-Video Sync problem. I wonder if someone can tell me how to fix this ...

I have an MKV file with 2 Audios on it (Hindi and English) and the Hindi plays by default. So, I want to remove the Hindi and leave English and make it Default ... here are my steps that I take ... but the Audio ends up Out-Of-Sync ...

Fo the purpose of Reference I will call my Original MKV file MKV-1 ...

1) Read MKV-1 with MediaInfo ... so I can get the FPS rate so it can be used later; FPS is 24.000 for this file.

2) Use MKVToolNix 5.5.0 Portable to uncheck Hindi Audio and put the 24.000 under Video and will not check the box under Audio for AAC ... since it is a Simple AAC audio. Then Mux this set up. Resulting in File MKV-1A.

The new MKV-1A file is out of Sync ...

I tried Media Player Classic to figure out how much Delay or Advance is needed to fix the Sync problem ... but can't quite find the spot ... even though the Audio Sync Loss is consistent throughout this MKV-1A file.

Q1: Any suggestion where I am going wrong?

Q2: Any better method of getting rid of the Hindi Audio and keeping Audio-Video Sync?

Thanks,

G!

[aedipuss]

try mkvmergegui open the mkv, uncheck the hindi audio, set the output folder/file name, click stat muxing.

[hello_hello]

Unless you want to change the frame rate, there's no need to specify one when you remux the MKV. In fact it's better not to. The frame rates reported by media info (as well as some of the other things it reports) tend to be rounded to nice even numbers and aren't 100% accurate.
As aedipuss said, all you should need to do is uncheck the unwanted audio stream and resave it as a new MKV. If that puts the audio stream you're keeping out of sync it'd be very unusual. Does MKVMergeGUI offer any errors when muxing?

[gonwk]

Hi folks,

1st of all Thanks to both of you guys for responding.

@ aedipuss ... just curious ... isn't MKVToolNix same as MKVMergeGUI!?!?

Well, hello_hello ... your explanation did the Trick ... I ran the same file thru MKVMergeGUI without telling it the FPS (under Video) and also did Not check the AAC box ... just unticked the Hindi Audio and let it rip ... MKVMergeGUI as before went thru with "Zero" error ... but to my surprise this time this New file plays Perfectly and No Audio-Video Sync problem.

Just FYI ... I remember reading somewhere on the net ... on MKVMergeGUI instruction that if the FPS of the Video was Different from 24.000 FPS ... it should be Selected ... otherwise there might cause an Error ... so I got in the Habit of doing that one extra step of reading the MediaInfo data on FPS.

Thanks again both of you folks!

G!

[hello_hello]

Yeah, unless you know you want to change something it's better to leave it alone as MKVMergeGUI will just pick up everything it needs from the source file. If you were muxing a raw video stream you needed to specify the frame rate or eartlier versions of MKVMerge would assume 25fps. Maybe that's what you read on the internet at some stage, but I don't think that's even necessary now. If it still is, MKVMerge will give you a frame rate warning message anyway.

Did MediaInfo report the original MKV as having a variable frame rate? If so that might be why specifying a frame rate put the audio sync out, or it may just not have been exactly 24fps to begin with. A variable frame rate sounds like a possibility. It'd explain why you couldn't find a delay amount which worked for the whole video using MPC-HC.

The only time you should ever need to check the AAC box is if you're adding a raw AAC stream to an MKV, and even then, only check it if you know you need to.

I'm happy you got it sorted anyway......

[gonwk]

... or eartlier versions of MKVMerge would assume 25fps. Maybe that's what you read on the internet at some stage, ...
...
The only time you should ever need to check the AAC box is if you're adding a raw AAC stream to an MKV, and even then, only check it if you know you need to.

I'm happy you got it sorted anyway......

Hi hello_hello ... You are exactly correct with your above description ... the 25fps comment was the reason that I was doing my routine ... but after Your Explanation ... I just run the MKV thru for cleaning parts out and works Perfect.

Also, just for the Benefit of the next person ... somewhere here I read that Checking/Ticking "Disable Header Removal Compression by Default" under File > Option > ... would Fix playback problem on Media Player ... and that did take care of my problem when I was using MKVMergeGUI ... without TickMark, it would make my resultant MKV Unplayable in my Netgear Media Player.

Appreciate all of Your Help & Time!

G!