Audio 25fps in mkv 23,96fps

[musclesly]

Hello,

I'm a newbie in the editing of video, but i have a problem with a mkv...
I explain:

I have a blu-ray rip into a container mkv 1080p (video 23,976fps) and i want to change the audio track (english) with a french one from my personal dvd...

I ripp the audio from the dvd into a wav or ac3 format in 25fps.
I extract the raw video from the mkv with mkvextract (in h264 format)
But the problem is when i used mkvmerge to place the audio track into the h264, i put the framerate of the video at 24000/101 and i stretch the audio at 23976/25000 but after rebuilding the mkv, the a/v are not synchro (i say i must readjust the sound with delay + or -) but when the audio looks ok in the beginning, after a few minute, the audio is complety desynchronised???

I also try to slowdown the audio with eac3to but no good result... my audio is more long at 23,976?

I also think one think: my movie in mkv 1080p is 88 minutes long and my dvd movie pal is 92 minutes long, can the differents framerates (23,976 for the mkv and 25fps for the dvd) can affect the total length of the movie??? (they are the same movie with the same scenes, not a director cut or something else)? , the movie cannot be longer because the framerate is a higher?

Is someone can help me? I hope my english is good (i'm french )

Thanks

[jagabo]

can the differents framerates (23,976 for the mkv and 25fps for the dvd) can affect the total length of the movie???

Of course. Take a deck of 52 cards. Flip them over 1 card per second. How long does it take to go through the entire deck? 52 seconds. Now flip them over at 2 cards per second. How long does it take? 26 seconds.

Increasing the film frame rate from 24 fps to 25 fps (and speeding up the audio) is the normal process for PAL video. And for NTSC the film is slowed to 23.976 fps. The difference between 88 and 92 minutes is about right for this. But you said the NTSC version is shorter than the PAL version -- that's backwards. Normally the PAL release has a ~4 percent shorter running time. You have different cuts of the movie.

[musclesly]

can the differents framerates (23,976 for the mkv and 25fps for the dvd) can affect the total length of the movie???

Of course. Take a deck of 52 cards. Flip them over 1 card per second. How long does it take to go through the entire deck? 52 seconds. Now flip them over at 2 cards per second. How long does it take? 26 seconds.

Increasing the film frame rate from 24 fps to 25 fps (and speeding up the audio) is the normal process for PAL video. And for NTSC the film is slowed to 23.976 fps. The difference between 88 and 92 minutes is about right for this. But you said the NTSC version is shorter than the PAL version -- that's backwards. Normally the PAL release has a ~4 percent shorter running time. You have different cuts of the movie.

Ok i begin to understand! I thought that it was the contrary that the 25fps is longer than the 23,976 not the other side, ok i admit that i don't look all parts of the 2 versions of the movie in the same time to see difference...

Then all PAL movie are shorter in time that the other in 23.976?

Thanks for your help

[jagabo]

Then all PAL movie are shorter in time that the other in 23.976?

Usually. There are some other techniques that can result in the same running time.

[Gavino]

I thought that it was the contrary that the 25fps is longer than the 23,976 not the other side

If you drive at 25 km/h you will get to your destination sooner than driving at 23,976 km/h.