Notes on ScopePort

I am planning to create a ScopePort screencast soon. I had no experience with screencasts when I started to work on that topic. This is why I encountered two main problems:

• How do I create the video?
• How do I add sound to that video?

The first problem was solved easily. I tried a few screen recorders and decided to use recordmydesktop. The main advantage of recordmydesktop is that it captures everything in a raw mode and encodes it when you stop recording. That makes it possible to record your screen without bigger speed problems. Everything looks pretty smooth and is usable for a screencast.

The second problem cost me a lot of Google searching. How can I add sound to that video? Here is the way I finally used:

First step: Capture the video

No Problem. I started recordmydesktop with the following parameters to capture only the first screen, with a fake cursor (the original one from KDE4 caused some problems) and with no sound. The sleep 3 before the execution of recordmydesktop gives me some time to close the shell and get ready to record.

sleep 3 && recordmydesktop -width 1680 -height 1050 -dummy-cursor black --no-sound

Second step: Convert the captured video to AVI

The file recordmydesktop creates is in a OGG format. That is usually fine but we require an AVI file to add the sound. I converted the OGG file to AVI with mencoder (Usually available in your favorite repository):

mencoder -idx screencast.ogg -ovc lavc -oac mp3lame -o screencast.avi

Third and last step: Add the audio

Now we can edit the video file with avidemux (also usually available in your repositories). Select “Audio” -> “Main Track”.

Now select a AC3, MP3 or WAV file that should be added as the main audio track. Press okay, select “File” -> “Save” -> “Save video” and you are done. That’s it.

If you use Fedora with PulseAudio and have the problem that you don’t get sound in Flash (SWF) your system might be missing the “libflashsupport” package.

yum install libflashsupport

In my case the audio channel of the Youtube video was flickering in the Pulse Audio control and there was no sound at all.