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Screencasting in Linux

Sharing ideas and experience about capturing screencasts in Linux.

Today I finished my new video tutorial about making screencast in Linux. This screencast is the result of my recent work on making video screencast in Linux. I have been trying many applications for recording screencasts, recommended by different users. My intention was to make such video material that will be classified as HD video on YouTube. Besides, I tried to achieve the same quality of video and audio that I learned to get on Windows.

So, I can say that screencasting in Linux can be as easy as screencasting in any other operating system. The most difficult issue is to select the most suitable software among many and many available applications. In any case, I prefer using free open-source applications, so my search for suitable software was limited to free applications.

After dozens of videos recorded I learned one of the important lessons and here it is: Tip 1: Record audio and video streams separately. What this gives me is the control over 2 streams which I can edit, clean, and finetune. Besides, in this case synchronization issues do not emerge, and I have no problems with making audio and video synchronized.

The principle of my recording screencasts was the following: I recorded video and audio streams separately, then I edited and cleaned them. After that I combined them into a single video which I later uploaded into YouTube.

Step 1. Capture Video Stream

For video capturing I used qt-RecordMyDesktop that is a fine desktop session recorder for Linux. Even though RecordMyDesktop allows recording both video and audio streams, I preferred capturing video stream only (to disable audio recording make sure 'Sound Quality' box is not checked).

recordmydesktop

With 'Select Window' button I selected the necessary window to make the recordings within. With hitting the 'Record' button I launched screen capturing. The important note worth mentioning here is the size of the window to record. If you want to upload your screencasts to YouTube and want them to be recognized as High Definition (HD) videos, make sure to keep the recommended aspect ratio, and video resolution that should be 16:9. So, Tip 2: While recording video stream keep to the recommended window size proportion - 16:9. In my case I recorded within Firefox web browser window that was 1270 px width, so the height of the window was 714 px (1270 to 714 is the same proportion as 16 to 9).

As a result of the recording I got out.ogv file, which I had to convert to a suitable format for subsequent work. What I used for this purpose was a mencoder, I run the following command in the terminal to convert my .ogv file to .avi:

mencoder out.ogv -o out.avi -ovc lavc

where out.ogv - is the input file, recorded with RecordMyDesktop, out.avi - output file needed for future word, -ovc lavc - is the the codec used for conversion.

Step 2. Record Audio Stream

To record the audio path I used Audacity sound editor. I usually open the video file in the background and while it is played I record audio stream for it. This gives me an understanding about how long the audio should be and this is how I can make my audio and video streams synchronized.

audacity

Audacity is a good application for making audio stream clean and distinct. It allows to get rid of the background noise that is usually recorded but it makes the audio sound a bit 'dirty'. Tip 3: Always try to minimize background noise while recording, if it still bothers you - use a good sound editor like Audacity to get rid of it. Here are the instruction how to do this:

  • Select a piece of the audio with no voice, only the background noise.
  • Go to Effect -> Noise Removal -> Click on Get Noise Profile
  • Select the whole audio stream and again go to Effect -> Noise Removal and press OK.

Now listen to what you've got now. Sounds better, doesn't it? What is left to do is to export this audio track in the .wav format.

Step 3. Combine a video with an audio track

The final step of the screencast making is to combine video and audio steams into a single video file. For this I used Avidemux application. Simply open necessary video .avi file, add the audio stream at Audio -> Main Track, and insert the External WAV (the one recorded with Audacity).

avidemux

Now that our video is complete - save this video at File -> Save -> Save Video. That is it! The screencast is ready for the upload to YouTube!

Here is the video tutorial about making screencasts in Linux using applications mentioned above:

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