I don’t know about you guys, but I love dvd commentaries. I’m not entirely sure why, but I do. And just about as much as I love audio commentaries, I love linux, transcoding, and my avel linkplayer2. Why you may ask? Because the synergy of those things allows me to be lazy and just watch movies without having to deal with the phyical dvds. BUT, it also means that the movies that I watch don’t have the commentaries on them. So, when I do own a great movie, such as Garden State, I figure, hey, I’m a reasonably bright individual, why don’t you re-encode the movie to include the audio commentaries? Well, that’s just what I did, and I’m going to tell you how I did it.

Rip & transcode w/ dvdrip. This gives you a project directory in ~/.dvdrip, the vob files, and a shiny, newly-ripped avi. For me this took about 2.5 hours and made my system virtually unusable. Load avg was over 10 for the duration. :( Time for new ram. 2GB anyone? :)

Rip the audio from the vobs like so (the vobs are in the directory vob/001/):

tccat -i "vob/001/" -t vob -d 0 -S 0 | tcdemux -a 2 -x ac3 -S 0 -M 2 \\
 -d 0 | tcextract -t vob -a 2 -x ac3 -d 0 > commentary-1.ac3
tccat -i "vob/001/" -t vob -d 0 -S 0 | tcdemux -a 3 -x ac3 -S 0 -M 2 \\
 -d 0 | tcextract -t vob -a 3 -x ac3 -d 0 > commentary-2.ac3

Garden State has 4 ac3 audio tracks: 0 is english, 1 is spanish, 2 is the first commentary, and 3 is the second commentary.

Add the commentaries to the original avi:

avimerge -o tmp.avi -i garden_state_xvid_dvdrip.avi -p commentary-1.ac3
avimerge -o garden_state_xvid_dvdrip_with_commentary.avi -i tmp.avi \\
 -p commentary-2.ac3

Voila! Now you have an even shinier and newer avi with 3 total audio tracks and 2 new audio commentaries. Looks like each new audio track cost us roughly 141MB! in additional storage space, but, hey, it’s worth it.

Tune in next time for another installment of Thomas’s Cool and Overly Complex Technology, we’ll discuss the possible advantages of the new h264 codec to improve quality while decreasing filesize.

References:
http://gentoo-wiki.com/HOWTO_DVD-Ripping
http://dominia.org/djao/dvdsub.html
http://www.transcoding.org/cgi-bin/transcode?Command_Examples/Multi-Audio_AVI-Files
http://www.transcoding.org/cgi-bin/transcode?Command_Examples/Pass-Through_Modes
http://www.bunkus.org/dvdripping4linux/single/index.html#tricks_extraaudio

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