install the old ffmpeg on ubuntu

see http://askubuntu.com/a/373509

I copy the steps here:

sudo apt-get remove ffmpeg
sudo apt-get purge libav-tools
sudo add-apt-repository ppa:jon-severinsson/ffmpeg
sudo apt-get update
sudo apt-get dist-upgrade
sudo apt-get install ffmpeg
sudo apt-get install frei0r-plugins
sudo apt-get --purge auto remove

Image sequence to a video clip on Linux

using ffmpeg in an essential form:

ffmpeg -start_number n -i test_%d.jpg -vcodec mpeg4 test.avi

with more control:

ffmpeg -f image2 -framerate 25 -pattern_type sequence -start_number 1234 -r 3 -i img_%04d.jpg -s 720x480 test.avi

using mkmpeg4 script, which requires mplayer on Linux:

mkmpeg4 -o output.avi -f 30 `ls *.png`

references:
http://www.shawnlankton.com/2007/04/videos-in-matlab-and-linux/
http://geodynamics.org/svn/cig/seismo/3D/SPECFEM3D/trunk/utils/Visualization/GMT/grenoble_basin_GMT_movies/mkmpeg4.py
http://superuser.com/questions/624567/ffmpeg-create-a-video-from-images