View Full Version : MAC: taking the audio from an AVI and then putting it back

2007-10-20, 07:08 PM
So I learned how to do this with a DVD. Awesome! I know want to fix some audio on a AVI file. It is already low quality as it is so I do not want to reencode the footage. I want to fix the audio and put it back on. I can only think of using iMovie. I cant get mpeg streamclip or ffmpegx to help do what I want to. Any ideas?

2007-10-20, 09:18 PM
Your options are to use avidemux (http://fixounet.free.fr/avidemux/) (for which you must have X11 installed) or a more roundabout route of converting the AVI to MKV (using MkvMerge (http://www.bunkus.org/videotools/mkvtoolnix/) and then demuxing with MoKgVm2DVD (http://www.emmgunn.com/). You can edit the resultant MP3 without decompressing/recompressing with Fission (http://www.rogueamoeba.com/fission/). I think you can remux with avidemux and I'd advise that rather than using ffmpegX but your mileage may vary.

When you were successful with your previous project, how did you overcome the problem with chapters ? Please see the relevant thread for the precise questions I'd like you to answer.


2007-10-20, 09:31 PM
BTW, it's Mac not MAC (http://en.wikipedia.org/wiki/MAC_address) ;)

2007-10-21, 10:51 AM
I'm checking out AviDemux. Following the pretty obvious instructions from this tutorial (http://www.avidemux.org/admWiki/index.php?title=Save_only_audio) I am not having good luck. It only gives me an 82mb file that doesn't want to open with anything. This is a divx of a 90 minute film (out of print, vhs transfer). I'll keep poking around.

2007-10-21, 11:03 AM
When I load the AVI it gives me a message about the audio being VBR and asks to build a time map to keep the sync. I don't know if that helps.

2007-10-21, 12:11 PM
Okay. I was making a mistake and now have it working. I just have to get the remux proper now.

2007-10-22, 01:57 PM
I have a snag muxing the new WAV file onto the footage. Any suggestions? I think I figured out how to open a second audio track on the avi in avidemux. I also figured out how to export and avi. I can't figure out how to tell avidemux to only use the new audio track.

2007-10-23, 11:38 AM
Sorry, I can't get to my main box at the moment (kid playing WoW) but you could try opening the double audio AVI in MPEG Streamclip, selecting the audio track you don't want and then opting for Delete Audio Track from the Edit menu. Save the file and see what gives.

2007-10-23, 12:02 PM
I forgot to say that you select the audio track to be whacked in the Audio PID box at the bottom.

2007-10-23, 09:39 PM
Thanks. I got it to work. I then found out that both the origional and of course the one I worked on fall out of sync with the footage. I may just import it to iMovie and try to resync scenes. Makes me wish I had the foresight to buy out cool VHS tapes from Mom and Pop shops. Then I wouldn't be trying to remaster DivX of out of print old films. :rolleyes: