Rebuilding ffmpeg to create screencast in Ubuntu

I was assigned to record a screencast for demonstrating look-and-feel of a portal. By the way, my laptop is Ubuntu right now. I don't want to find another machine to do this job so I have to find a way to record my screen effectively. I found How to Create a Screencast in Ubuntu. This is a good article which helps me realize additional capability of ffmpeg. Anyway, the standard ffmpeg does not support this functionality so I have to recompile ffmpeg by myself. Well, I do not like this idea because I will have two versions of ffmpeg in different directory. So I continue finding and finally found how to rebuild ffmpeg in proper way. As a result, I combined 2 approaches as follows.

  1. Prepare all necessary packages to build ffmpeg from source
    $ sudo apt-get build-dep ffmpeg

  2. Install additional packages to build risky addons of ffmpeg
    sudo apt-get install liblame-dev libfaad2-dev libfaac-dev libxvidcore4-dev fakeroot
    sudo apt-get install build-essential xlibs-dev devscripts

  3. Get ffmpeg source
    sudo apt-get source ffmpeg

  4. Get x11grab patch
    wget http://un.sh.nu/screencasts/ffmpeg-0.4.9-p20051216.diff

  5. Apply the patch (You may get 2 failures in file configure. Don't worry. Edit the file manually will help.)
    cd ffmpeg_0.cvs20050918
    patch -Np1 -i ../ffmpeg-0.4.9-p20051216.diff

  6. Modify debian/rules to include below line
    confflags += --enable-x11grab

  7. Modify debian/changelog to describe about your modification and version number to prevent autoupdater override this package automatically
    ffmpeg (3:0.cvs20050918-5ubuntu1.x11grab) dapper; urgency=low

    * x11grab:
    + Add support for x11grab

    -- Sugree Phatanapherom <sugree@gmail.com> Wed, 21 Jun 2006 21:50:00 +0700

  8. Rebuild ffmpeg
    $ DEB_BUILD_OPTIONS=risky debuild -us -uc

  9. Install the package
    $ cd ..
    $ dpkg -i ffmpeg_0.cvs20050918-5ubuntu1.x11grab_i386.deb

Now I have a customized version of ffmpeg which supports x11grab extension for real-time recording screen and another audio source with the same build options of that in original ffmpeg compiled. In order to record a screencast, I just run below command.
$ ffmpeg -vcodec mpeg4 -b 1000 -r 10 -g 300 -vd x11:0,0 -s 1280x768 -an test.avi
where:
  • -vd x11:0,0 specify x11 as video device at offset x=0 and y=0
  • -b 1000 specify video bitrate
  • -r 10 specify video frame rate
  • -s 1280x768 specify video size
  • -an specify to exclude audio
If you want to record audio, just ignore -an and run ffmpeg under esddsp to make it run concurrently with other application properly. To resize the video, run below command.
$ ffmpeg -vcodec mpeg4 -b 1000 -r 10 -g 300 -i test.avi -s 800x600 test-800-600.avi
Now it's time to play.
$ mplayer -vo x11 test.avi
Happy screencast!

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