One of the handiest tools in my Linux toolchest is Ffmpeg, the universal media transcoder. I'm pretty sure this fantasically useful piece of software runs in the background of every service that converts audio or video from one format to another (Google video, YouTube, Archive.org, etc). Over the years I've amassed a small collection of commands that will allow me to take media from one source and convert it for use in another - for example ripping video from a DVD or the web and then editing it and burning it back to DVD. Hopefully these will prove to be of use to you:

1) Converting video to DVD-compatible MPEG2:

ffmpeg -y -i inputfile.xyz -vcodec mpeg2video -target ntsc-dvd -r ntsc -deinterlace -aspect 4:3 outputfile.m2v


2) Converting video for the web (w/o frame size reduction):

ffmpeg -i inputfile.xyz -f avi -vcodec mpeg4 -ab 128 output.avi


3) Convert DVD (MPEG2) files to MPEG4:

ffmpeg -i inputfile.vob -f avi -vcodec mpeg4 -b 800 -g 300 -bf 2 outputfile.avi


4) Prepare for Gen5 video podcast:

ffmpeg -i inputfile.xyz -f mp4 -vcodec mpeg4 -maxrate 1000 -b 700 -qmin 3 -qmax 5 -bufsize 4096 -g 300 -acodec aac -ar 44100 -ab 192 -s 320x240 -aspect 4:3 outpulfile.m4v

or

ffmpeg -i inputfile.xyz -f mp4 -vcodec mpeg4 -maxrate 2500 -b 1800 -qmin 3 -qmax 5 -bufsize 4096 -g 300 -acodec aac -ar 44100 -ab 128 -s 320×240 -aspect 4:3 outputfile.m4v


5) Prepare Cinelerra edited .DV (from Canon GL1*) for Google video upload:

ffmpeg -i inputfile.dv -f avi -vcodec mpeg4 -cropleft 8 -cropright 4 -s 640x480 -b 1200 -g 300 -bf 2 -acodec mp3 -ab 128 outputfile.avi


6) Convert electric sheep for Resiloom:

ffmpeg -i inputfile.mpg -f avi -vcodec mpeg4 -s 640x480 -b 6000 -g 300 -bf 2 -acodec mp3 -ab 128 outputfile.avi


7) Convert to raw DV (eg. for editing in Cinelerra or Apple FCP):

ffmpeg -i inputfile.xyz -target ntsc-dv outputfile.dv

* The Canon GL1 does not shoot a full 720x480. This command include the options to remove the black bands that the GL1 adds to the sides of DV video during the transcode.