Change framerate in .mp4

[Merick]

I've got an h264 video in an *.mp4 container. The audio in the file is the correct length at just over 24 minutes, but the framerate for the video slightly slower and runs for 30 minutes.

What's the easiest editor to use to speed up the video to make it match the audio?

[paglamon]

AVIDemux.

[Merick]

Thanks, that fixed it

[paglamon]

[Merick]

Been busy, meant to get back to this earlier..

Seems it didn't fix it quit as well as I had thought at first, it still got de-synced towards the end. I've tried to redo it a few times, but I can't quite get the framerate to the correct speed. There's also the problem that the file uses B-frames, which makes AVIDemux crash

[gonwk]

Hi folks,

@ Merick ... how much of it is out-of-sync!?!? May be save teh good part ... cut the bad part ... demux ... correct timing and mux up ... then combine with the good part. It is a pain in the neck ... but if you are bored and have nothing better to do ... can be done (I did it on one old film that it was from 1920's).

@ Paglamon ... I see you are back ... WELCOME BACK!

G!

[Merick]

In the original file, the video is already a few seconds behind the audio during the opening sequence, and at the end it continues to run to 30 minutes, which is 6 minutes after the audio track is finished.

When I loaded it into avidemux, I left it as a straight copy in the audio/video options shown to the left side of the video output window. In the video->framerate menu I selected the standard ntsc 30 fps (the original is at 23.9fps). This brought the video time down to 24.15 minutes. At the beginning of the file the everything seems fine, but the video is still slightly slower and by the end of the episode it's behind by a few seconds.

I've tried changing the framerate by fractions of a second, but I always end up with the video being either slightly slower or slightly faster than the audio.

Also, if I try to load the file without using "safe mode" (because it uses b-frames), it tells me "Index is not up to date", but if I try rebuild the keyframes it crashes

[gonwk]

Hi Merick,

I can't recall my exact steps ... but I think I demuxed the Audio and Video ... then I cut out just enough from the beginning of the Audio to match the Video and then Muxed it back up ... I had to try it out several times to get it right.

I know this is not a step-by-step help ... but sorry ... I can't even remember how many freewares I used to do it.

Also, I did another one that I ahd to chop the AVI into 7 or 8 portions since the Audio was not out-of-sync consistently throughout the video ...and that was a challenge ... but I got the darn thing working pretty good!

G!

[MilesAhead]

@Merick it sounds like you may need to use Pulldown. I'm not quite
sure how it works in avi to avi encoding but when converting avi to dvd I
can remember keeping the frame rate the same then using DGPulldown to set
the video to play correctly without throwing the audio out of sync. Tools
like FAVC do it automatically now. A google may pick up some hints.