I would like to convert a whatever-type video file into an ISO image I could then burn to a DVD (on another computer) - so that the final disc is playable on a regular DVD player.
I already have ffmpeg installed with medibuntu, and mpeg output support does seem to work.
Is there a command line tool, or a simple script that I could use to do this?
You need specifically mpeg2 output (mpeg1 will do, if you don't mind the loss of resolution, but mpeg4 is outside the spec). You probably want PAL 720x576 25fps 16:9, with MPEG-1 or AC3 audio; or for NTSC 720x480 and 23.97fps (or whatevs). However, you can use the "dvd" target preset to make things easy, simply by running ffmpeg -i input.avi -target dvd video.mpg
To turn the mpeg file to an DVD compatible folder structure, you need a tool like dvdauthor. There are probably some frontends to it, but the first example from the book, chapter 1.2, is probably sufficient for you. Put that example into file dvdauthor.xml and your video to video.mpg and execute dvdauthor -o DVD -x dvdauthor.xml.
This will result in a directory structure under folder DVD, which you can turn in to an iso file with genisoimage -dvd-video -o my.iso -v DVD. You can then copy my.iso to some other system and burn on a disc with wodim or some other tool.
The resulting disc should be playable in standalone players, but due to DVD limitations you may run into problems with arbitrary mpeg streams. Some of the problems may be fixed with dvdauthor and others with mplex from package mjpegtools. If you want subtitles, you'll need to learn how to use spumux.
