mkv frame rate issues: audio and video out of sync

[abcmkv]

Hello. Please forgive me for my inexperience with this. I have encoded an MKV file with makemkv in which, on playing back in VLC and other players, the audio and video go out of sync: the video is slightly faster than the audio. This was not a problem with the original DVD. Apparently the frame rate for the MKV file is 25fps, whereas I would have assumed it should be 23.976 -- and I'm guessing that's the reason that the video is running slightly faster than the audio.

Is there any way I can fix this MKV file? I'm running the latest OSX if that's any help.

Many thanks in advance! (And sorry if I've posted in the wrong forum)

[Woodstock]

When you ripped the disk originally, did MakeMKV log any messages about trying to synchronize the audio and video tracks?

[abcmkv]

Thanks for your response. Unfortunately I didn't have the presence of mind to note down any messages, but I don't recall it doing so.

[abcmkv]

I have now tried remaking the MKV, and have run into the same problem. No error messages are reported. If anyone could please help, I would very much appreciate it!

[Woodstock]

A frame rate of 25 is consistent with a PAL-encoded DVD. Was this disk for Region 2?

One possibility is to recode the video using something like handbrake, which can often match up the frame rate between the audio and video tracks.

But MakeMKV is going to simply copy the tracks from the DVD to the MKV file, leaving them with whatever anomalies they started out with.

[abcmkv]

Thanks -- it is region 2. It looks like the DVD was originally encoded at 25fps, according to VLC. The thing is, the DVD plays fine on my computer otherwise, it is only when it is encoded to MKV that it goes out of sync.

[abcmkv]

I will try re-encoding it with handbrake -- thanks for the tip.

[Woodstock]

According to the people over on the handbrake forum, a common way to deal with PAL video is to take a 24 FPS source and simply play it at 25FPS. The audio is sped up slightly, but most people don't notice it unless they've watched the original 24 FPS film recently enough to compare. When you play it back at 24 FPS, the audio is "too short" to match, so it gets ahead of the video rather quickly.

Some players take this into account when the source is DVD, but they may NOT when playing an MKV made from the same DVD.

NTSC is a bit more complex, because you're going from 24 FPS to just shy of 30, so there are extra frames injected to make it work. But the audio speed isn't changed when this happens.