Getting started Screencasting with Linux and open source software was an adventure. I was looking for a single tool that could do all the editing for audio, video and effects. What I came up with is a combination of Kdenlive, Audacity, RecordMyDesktop, and a couple command line tools.
- Analog Microphone - Specifically an Xbox 360 headset with an adapter from 2.5mm to the PC's 3.5mm plug
- VirtualBox - for running the demonstration computer within a window
- RecordMyDesktop - records both audio and video of the selected window
- Audacity - used to filter the sound recorded by RecordMyDesktop
- Kdenlive - for video editing
- mencoder - terminal based program for converting the video
- Gimp - for creating static images
- Youtube - for publishing
Software and Hardware
Xbox 360 Microphone
Before I committed to purchasing an expensive screencasting setup I wanted a cheap microphone to get started. The only headset mic I had was a turtle beach Xbox gaming headset. The mic on the headset uses a simple 2.5mm analog output, but my PC has a 3.5mm input. I ran to my local electronics store and purchased a stereo 2.5mm female to 3.5mm male converter. The headset only uses the left channel and the audio is changed to mono with Audacity. I had to tune the preamp and mic volume using alsamixer. Open a terminal and type alsamixer then hit enter. This will bring up a simple graphic in the terminal that shows all the audio devices and the associated volume levels.
VirtualBox
I use VirtualBox for my VMs, but also have VMware installed and I have heard that QEMU works just as well. The advantage of using a VM is that the resolution can be adjusted to match the final published resolution. Choosing a small resolution will increase the readability of text and small details. If the resolution is small enough then it is possible to display RecordMyDesktop on one half of the screen and the VM on the other. Also, using a clean install of the operating system is a good idea so that the setup is near to stock as possible.
RecordMyDesktop
This is a very simple utility that records the whole desktop or selected windows. One thing to keep in mind is that it records sections of the screen and doesn't truly record a single window. This means that once the recording starts the selected window shouldn't be moved, or other windows be allowed to cover it. RecordMyDesktop saves the video in .ogv format.
Audacity
The audio from my simple microphone isn't clean. Since Kdenlive doesn't have good audio filters; I export the audio and open it in Audacity, apply the filters I want, and then import it back into Kdenlive. To make it easier to sync the audio with the video I don't trim or cut the track in Audacity.
kdenlive
Kdenlive is a nice GUI for editing videos and sound tracks. It is limited to simple cut and paste operations, but still has multiple tracks for both audio and video. Kdenlive is available in the Ubuntu Software Center. I am using Ubuntu 12.04 and the Kdenlive installation worked the first time without any configuration. The only trick was that Kdenlive had issues editing video in the ogg format. To fix the video editing issue I converted the video with mencoder to .avi format.
mencoder
I use mencoder to convert the video, but it is also possible to use ffmpeg. The command is very similar for both tools. For the following command take1.ogv is the video from RecordMyDesktop and out.avi is the video I will import into Kdenlive.
$ mencoder -idx take1.ogv -o out.avi -oac mp3lame -ovc lavc
Gimp
Gimp is a great image editor available on Ubuntu. For the screen casts I use it to create intro and outro screens as well as add effects to the video. I create a new image with the same resolution as the screencast and then save it as .png for importing into Kdenlive. If I only want the image to cover part of the video I set the background to be clear.
Youtube
I use Youtube for publishing my videos. It was a simple choice since it is already setup with some of the other online tools I use. Vimeo is another great option, especially if design and consistency are import. Youtube has a tendency to suggest videos in the sidebar that can be NSFW.