Merge video file with mp3 file - What do I need to know?

[Grobe]

Hi.

I've found Avidemux very useful for mixing sounds into timelapse videos. I do have some general questions avout merging mp3 files with video files:

1
How close must the length of the audio track be compared with video track? If my video track is 1 minute sharp, I'm I allowed to merge an mp3 file that is 61 or 59 seconds long duration? Or must clip it so that file match the exact length of the video file?

2
I like to use Lame in conjunction to "Lame Fronted" to convert MP3 from wav with variable bitrate.
I know (think) that most vides files has an audio track (or stream?) with fixed bitrate.
A'm I able to merge VBR encoded mp3-files with any video file?

2b
In Lame Frontend, there is an option called "Enforce ISO bitstream". Does that option make it more likely that merging the MP3 file with a video file will succed?

3
For the question I've asked - will the anwer depends on the container format?
Ie. Will support of VBR mp3's depend on wheter the video is contained within an avi or mov container?

4
Anything else that is good to know?


Thanks

[Jan Gruuthuse]

Audacity has the possibility to work with frames instead of time index? source video working, audio track problem? Pay attention to the remarks of styrol in 2nd posting

[Grobe]

Thanks.

I do already use Audacity as my sound editor. However I seldom make very long vide clips so I cannot see having any use of "frames". Still It may be a nice thing to use in longer clips.

Any ideas on my question 1 to 4?

[nibbles]

Hi Grobe.  Good questions.  You might search Doom9 to see if they've been answered before.  They're fairly general.  Yes vbr mp3 will go into an avi, but there are caveats that I don't know.  I also don't if Avidemux will pad or truncate the audio.  I have a feeling that Avidemux2 will behave differently from Avidemux3 (one uses frames, the other uses timecodes as the basis for lining things up).