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Screencasting Under Linux--A brief Story

Submitted by gfranken on Friday 15th of January 2010 08:11:12 PM Filed under
Linux

My first consideration for making A/V screencasts under Linux is Software. What programs are available to do screen-recordings with simultaneous audio narration under Linux? I've probably tried them all: recordmydesktop (which has both gtk-recordmydesktop and qt-recordmydesktop GUI font ends), Istanbul, xvidcap, and wink. Frankly, none of these yielded the high-quality screen capture I wanted. But the real problem is that the audio quality was worse. After thrashing about, I finally end up with a non open source commercial product called DemoRecorder.

Now DemoRecorder is a commercial, proprietary program, which costs $47.00US, $77.00US, or $247.00US depending on the desired feature set. I purchased the $77.00 license. This does not work under Mandriva 2010 in nested desktop mode, but the openGL mode of capture works well. No dropped frames on the video side, and relativey smooth modion. On the audio side, no major sound glitches like I had with recordmydesktop.

Using DemoRecorder in the openGL mode is a two-phase process--Running the demorec --opengl program to perform the initial capture of the video and audio files, then the transcoding or assembly into a finished product using demorec-to-avi (or demorec-to-dv, demorec-to-flv, demorec-to-mpeg1, demorec-to-mpeg2, demorec-to-ogg-theora or whatever video codec/container you wish).

While the sound quality is considerably improved, it's still a bit hollow and tinny when recorded from my Logitech headset. I found the captured sound file produced by demorecorder, which I could then import into Audacity in raw format. I could then edit and improve the sound in Audacity, and export the edited sound file back to the drive before the assembly/transcoding of the video files and the sound file into one avi file.

This works--still, the sound isn't quite professional quality, but close. The real issue with this is that this type of post-production sound-editing takes a lot of time. Better, if possible, to get a high-quality sound recording to begin with, and bypass the editing step. Time for some research into sound production.

I have no experience in sound recording--I'm a computer guy, but I do like to play with hardware.
Fortunately, I already have a really good high-quality sound card in my working desktop computer--an HT Omega Claro Plus.

Turns out, you can get a decent quality mic, and a device called a sound mixer, and you can record really great sound. Good to know. I end up purchasing a Behringer XENYX 1204FX model mixer for $179.99US. This model of mixer turns out to be overkill on my part, and I now know I could have got by just fine with a cheaper mixer (prices for a mixer can range from $99.00US to several thousand US dollars).

As is often the case, one purchase often begets another. So, on to buy a decent, but relatively inexpensive condensor mike (after shelling out too many $$$ on the mixer). I end up purchasing an MXL 990 condenser microphone with a shock mount for $49.00US. Then a proLine desktop mic stand, model MS112 ($29.99US). Finally, I purchase assorted cables and adapters.

After all my sound gear arrives, I connect the mic to my mixer, the mixer to my sound card. Then I fire up Audacity to run some tests. After fiddling with the gear for about an hour, I'm amazed at the quality of the sound captures. Now I can start recording those educational screencasts in earnest.

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