I learned how to turn a DVD into a DivX today. The secret is
the program Gordian Knot
along with the
. It's very confusing hackerware, but the basic idea is
- Rip with SmartRipper. Produces VOB files - video objects ripped
from the DVD.
- Decode and parse with DVD2AVI. Produces AC3 audio files, as well
as a D2V file that seems to be a guide to the video in the VOB.
- Configure codec (DivX 3, in this case). Have to choose bitrate,
audio track, etc.
- Encode. Produces an AVI that the movie player can show.
Gordian knot tries to glue all these steps together for you. It's
hugely confusing, but the Doom9 guide helps. It helps a lot if you set
the Bitrate tab to "Calculate Avi File Size" - then you set quality
directly rather than trying to guess a quality to fit a certain size file.
End result - 3:1 compression ratio for something that still looks
very good (704x368@1600kbps, 160kbps MP3 audio). Three things would
make this process better:
- Encode direct from camera to MPEG-4, bypassing the MPEG-2 step
in the DVD.
- Variable bitrate encoding during construction of MPEG-4 stream.
Maybe DivX does this, but I don't think so. (Whoops,
Nandub, which I'm using, does do this.)
- Turn DivX encoding into a legitimate business so someone can write
a good front end. Rip, mix, burn.