Help creating screencasts on Ubuntu. keeping audio and video in sync

heathenx heathenx at
Mon Sep 15 16:32:01 BST 2008

tchomby wrote the following on 9/15/2008 11:17 AM:
> Ok, the technical support people here at the university are away until 
> tomorrow. If I don't fix this problem today then I'm gonna ask them to 
> install Windows for me tomorrow. I'd love to know why it is that I have 
> a sync problem and you don't. Does that suggest that it's because my 
> machine isn't up to spec? Maybe then I should try capturing a lower 
> res/smaller area?

Well, I'm sure your machine is better than mine. Like I said, I have a budget machine and it has 
served me well for my screencasts over

> I've been using recordmydesktop 0.3.6 from the repos.I looked at the 
> changelog, and there doesn't appear to be any important changes between 
> that and the latest version, but I think I'll try the latest anyway. 
> I'll try compiling xvidcap and caputring to avi too, if it can do that.
> On Mon, Sep 15, 2008 at 1:13 PM, heathenx <heathenx at 
> <mailto:heathenx at>> wrote:
>     An alternative way to screencast is to record without sound using
>     recordmydesktop and record sound
>     in Audacity at the same time. In other words both programs are
>     running at the same time, one
>     capturing video while the other captures sound. Some people use this
>     method. I was never really
>     found of it because it seems like more work.
> This is actually a fantastic idea, which hadn't occurred to me! It would 
> mean I could use my one-pass approach, but still produce two separate 
> files and then combine them later, which ostensibly is how you avoid 
> sync problems. Is there anyone here that uses this approach that can 
> write a little how-to for me?
> I don't know how to combine the files. Can anyone give me, or point me 
> to, a step-by-step for how to combine the audio and video and get them 
> in sync, using any video editor (or anything)?

There are quite a few ways to add an audio file to a video file. Perhaps you would find it easier to 
open your video file in Avidemux, then go to Audio and add a main track, and then save the file out. 
It's really that easy. Another way to add audio and video together is "mencoder -oac copy -ovc copy 
video.avi -audiofile audio.mp3 -o final.avi". Notice that I'm working with avi's and mp3's. Those 
two formats are easiest for me to work with. However, I'm not sure what is the best way to sync the 
files if they are out of sync. You can delay the sound with mencoder but I think it's trial and 
error. That might not be the best way to do things.


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