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

heathenx heathenx at gmail.com
Mon Sep 15 13:13:38 BST 2008


tchomby wrote the following on 9/15/2008 7:51 AM:
> Thanks heavenx. Does anyone know anything about my first problem, that 
> is that the audio and video are going out of sync in the initial OGG 
> file created by recordmydesktop? Before I even convert the file, or 
> import it into any editor. If I knew what was causing the problem maybe 
> I could get around it. I just need a program that can capture the screen 
> and audio at once, and keep both in sync. Maybe I should be using 
> different capture software, maybe compile xvidcap? (Since the hardy 
> package is broken.) Or is there something that can caputre to AVI 
> instead of OGG?
> 
> Is there anyone else that uses this one-pass approach, capturing the 
> audio and video at once, with success? Perhaps I should just bite the 
> bullet and go for the two-pass approach, first plan out everything I'm 
> going to do on screen and everything I'm going to say, then record the 
> screen only while still speaking out loud what I'm going to say for the 
> timing, then play it back and read the script out loud again to record 
> the audio, then open both files in an editor and combine them. It might 
> get around the sync problem. That sounds like it'll take twice as long 
> though, and if I ran into an unsolveable technical problem with that 
> approach too it would just be devastating at this point.
> 
> About the video editors, avidemux, kino, cinelerra, etc., can any of 
> them do anything to fix the audio and video syncing? What I imagine is 
> specifying a key point every two minutes or so where I manually line up 
> the audio and video streams. Kino seems like a fine editor, I have 
> learned to use it, it does everything I need easy enough, but the audio 
> and video just aren't staying in sync.
> 
> Thanks for the Camtasia recommendation, at least if I do have to move to 
> Windows I won't have to hunt around for the right software on that too, 
> I'll just go straight to Camtasia.

Unfortunately, I haven't had a problem with audio and video staying in sync. Perhaps I'm just lucky. 
I have a slightly pimped budget rig at home. Pretty basic. I've used openSUSE and now Ubuntu and 
screencasting has always worked flawlessly for me using recordmydesktop.

Are you using recordmydesktop from the Ubuntu repo (Hardy) or did you download the most recent 
version and compile it? The repo version is quite a few releases back but it's pretty stable and 
it's what I use. Also, you might want to try recording from the terminal instead of the gtk version. 
I know that might be a long shot but see if it's any better. Here are some sample commands that 
might help you:

Capture whole screen (change your device - I use a logitech usb mike)
recordmydesktop -fps 15 -device hw:1,0

Capture an application window (after executing click the app window that you wish to record)
recordmydesktop -windowid $( xwininfo -frame | awk '/Window id:/ {print $4}' ) -fps 15 -device hw:1,0

Type Ctrl+c to stop recording.

Xvidcap works pretty well too. I believe that you can record directly to xvid avi if you wish to use 
that. I would record into whatever format works best then worry about converting it later.

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.

heathenx



More information about the Ubuntu-screencasts mailing list