Screencasting on Linux Mint 17

Sometimes I post philosophical essays, and sometimes I describe important teaching experiences, and sometimes I reflect on my miniature painting hobby. Today, however, I go to that much more pragmatic use of the blog: writing down how I actually got screencasting to work on my work machine.

I have a Dell Precision T3600 running Linux Mint 17. I switched from KUbuntu to Mint on my work machines last year, when I had some trouble with hardware recognition. Since I've been using KDE for over a decade (from Mandrake to Mandriva to KUbuntu), I use the KDE distribution of Mint as well. It seems this puts me in the minority, as most of the Q&A I see online assumes one is running something newfangled.

I have USB Logitech headphones that used for the screencast. After a bit of fighting with my mixer, I was able to get the microphone to work: the system wants to default to the hardware ports, even when there's nothing connected there. Audacity makes it very easy to test the sound configuration, and so I was sure that the microphone was working.

However, getting that microphone to work through screencast software was another problem entirely. I had no luck with the old standard recordmydesktop at all: video capture was fine, but the audio came up with nothing. A bit of searching revealed some newer applications I had never heard of. Vokoscreen had a reasonable user-interface with several configuration options, and I was confident enough to record an 11-minute take. Unfortunately, upon playing back, the audio was terribly choppy. I spent quite a bit of time fiddling with the framerate and pulseaudio settings trying to fix this, since otherwise Vokoscreen was convenient to use, but a tutorial with no audio is hardly a tutorial at all. Since the mic was working fine in Audacity, I inferred that it was a software problem, not a hardware problem.

I switched over to Kazam, and this ended up doing the trick. It allowed me to select an area of the screen where I could hop between Eclipse, Chromium, and the console, and the audio was captured with no trouble. The default file format uploaded flawlessly to YouTube, and I was able to share the video with my students. I had actually tried Kazam before Vokoscreen, but it wasn't working—turns out it was because I had the mixer settings for my mic much too low, and they needed to be at almost 100%. (Recordmydesktop still did not work with this fix, incidentally.)

The screencast itself is just an explanation of how to set up a PlayN project and hook it up to a Mercurial repository using the Computer Science Department's Redmine server. Hopefully next time I want to do an 11-minute screencast, it will take less than two hours of tinkering.

Screencasting in Mandriva

I spent too much time today making a short screencast in order to demonstrate a specific property of Eclipse and Java. I could not find any clear recommendations on what software to use on Mandriva, my preferred Linux distribution, at least not beyond what was given on Wikipedia's page comparing screencast software.

I ended up using recordMyDesktop with the qt frontend, both of which were in the standard Mandriva repositories. You can select an area of the screen to record via the main window, but there is also a tray icon. Initiating a recording from the tray icon seems to always grab the whole screen, regardless of what is selected.

Additionally, the selection only seems to work if you choose the box and then hit record on the main window. Stopping that recording and then clicking record a second time results in having a full-desktop recording, which is not what I wanted. These complications caused me to have to throw away three reasonable takes, because it was easier to recreate them then to figure out how to crop a whole video. (Although if someone knows how to do that on Mandriva, let me know.)

With an acceptable take--although I forgot one important point, but am not willing to try yet again--I uploaded the file to YouTube. RecordMyDeskop produces Ogg Theora video output with Ogg Vorbis audio, which I think is great as a supporter of open formats. YouTube happily accepted the upload, recognizing it as Theory+Vorbis, and did its magical processing. The end result, unfortunately, had completely garbled video, just some colored flecks on the screen, while the audio worked fine.

A little scouring of the Web, and I discovered a Devede, a Linux application for mastering DVDs that can also be used to convert to AVI video format. After installing the requisite codecs, I was able to convert the ogv into avi, and I uploaded that to YouTube. Somehow it got confused and thought I cancelled the upload, so I had to do this twice, but the final one stuck.

This worked for me, but if anyone knows of a simpler and more streamlined process, I'm open to ideas.