This article is from the CD-Recordable FAQ, by Andy McFadden (email@example.com) with numerous contributions by others.
It isn't possible to take the contents of a DVD-Video or DVD-ROM and
record the whole thing onto a CD-R, unless the DVD is nearly empty.
The capacity of DVD discs is considerably greater. Generally speaking,
you can't play DVD content from a CD-R disc anyway, because the DVD drive
needs to read encryption keys from outside the filesystem area.
You could, of course, capture the video from a DVD-Video disc with a video
capture board, re-encode it with MPEG-1, and write that as a VideoCD.
The quality would be VHS-grade though. (You can get better results
with MP3 audio and MPEG-4 video, but the process is a little convoluted.
See http://www.digital-digest.com/dvd/support/dvd2mpeg4.html.) The
next section talks about some ads you might have seen for products that
You may have heard of DivX (sometimes "DivX ;-)"). Originally the name
for a limited-playback DVD system, it now usually refers to MPEG-4 encoding
of DVD video. See http://www.divx-digest.com/help.html for more details.
If you're only interested in the audio portion of a DVD-Video, you can
extract the AC3 audio directly from the .VOB file, using some freely
available utilities (notably "ac3dec" and the elusive "DeCSS"). You will
need to convert the audio from 48KHz to 44.1KHz. You can also capture
it under Windows with Total Recorder (6-2-19).
The story is the same with DVD-ROM: you can probably copy it to a CD-R if
it will fit. If the contents only took up about 650MB, though, it probably
wouldn't have been shipped on a DVD-ROM.