Most high-performance video codecs are encumbered with patents. Not so long ago, a new version of the Theora video codec was released with improved performance. I tested it with version 0.25 of ffmpeg2theora, which creates files with Vorbis sound and Theora video.
The mpg file was produced with
mplayer dvd://1 -dumpstream -dumpfile movie.mpg
Converting to avi format was done with:
mencoder -profile hqmovie -o movie.avi movie.mpg
This profile is covered further down on this page. The ogv file was created with the command:
ffmpeg2theora --sync --aspect 16:9 --croptop 8, --cropbottom 8 -v 7 -c2 movie.mpg
The difference in size between the avi and the ogv file is impressive, especially since I cannot see much difference in quality. The only snag is that mencoder seems to do a better job of creating a better sounding stereo sound from e.g. a AC3 stream. Therefore I tend to do a quick resample of only the sound with:
mencoder -ovc copy -oac mp3lame -idx -o movie-int.avi movie.mpg
|movie.mpg||MPEG2+AC3||as ripped||6478 MiB|
|movie-int.avi||MPEG2+MP3||sound resampled to MP3||5806 MiB|
|movie.avi||H.264 +MP3||by mencoder (from original MPG)||4481 MiB|
|movie.ogv||Theora/Vorbis||by ffmpeg2theora (from original MPG)||1999 MiB|
|movie2.ogv||Theora/Vorbis||by ffmpeg2theora (from resampled AVI)||1750 MiB|
I cannot see or hear much of a difference between the H.264+MP3 encoded movie and the one encoded with Theora+Vorbis. The H.264 avi file made by mencoder is 70% of the size of the original mpg file. The ogv files are 30% of the size of their original mpg files, and are in my eyes of equal quality to the H.264 encodd AVI files. And since Ogg/Theora is not encumbered with patents like H.264, it makes me think that theora+vorbis is a better choice for encoding video now. I've encoded other movies as well, and constantly find that the size of the theora+vorbis encoded film is around 30-40% of the size of a H.264+MP3 encoding.
For feature films, file size in this OGV format range from 1051 MiB for a 97 minute standard format movie, via 1750 MiB for a 147 minute widescreen movie to 2988 MiB for a 207 minute black/white movie.