Ok, I'm trying to figure out the easiest way of backing up my DVD collection - while I have considered DivX and a new DVD player that can use those, I would rather just be able to burn pukka DVD-Rs (since I have a nice little powerbook with a DVD burner)

The problem comes with large/long films that wont fit onto the 4.7GB DVD-Rs. Now as far as I can tell resampling the MPEG2 to a lower bit rate should not be a problem for mencoder.

However rather than trial and error, is there anyone else that has done this that could provide me some advice on the config:

What audio codec should I use and which settings?
What is the default video bitrate for comercial DVDs?
What is a sensible minimum to use for the video encoding bitrate?
(I'm using the lavc codec for video encoding, I presume this is the best idea?)


The next problem comes with with trying to build this mpeg video back into a DVD-R. I've been trying with iDVD (which comes free on OSX) and I cant seem to get it to accept the created avi file from mencoder. Am I doing something wrong?

I did come across a linux tool for doing this, and since all I want is a single play movie button it should not be a problem (however the main reason I was trying to get it to work in iDVD is if it works there I know I wont end up burning something that no DVD player can use)

Thanks all,


Oh and I know there are various utilities for windows or OSX which do this but these are not an option I want to use as:

1. I dont like payware/shareware
2. I like to know exactly what is going on
3. I prefer using the command line (so I can script it all)


Simon

Check out tovid, a script I wrote for converting video to DVD and other formats. I've found mencoder itself to be somewhat flaky for creating mpeg2 video (which DVDs must be), so my script calls upon utilities in the mjpegtools package.

As for choosing the right bitrate, from what I can tell the mjpegtools mpeg2 encoder uses a variable bitrate, up to the limit you specify. In my script, there's a constant you can set for the maximum bitrate, but I've found most video to fall below about 7500kbps (the default bitrate for mpeg2enc). At that bitrate, you're guaranteed to fit about 81 minutes of video and audio on a 4.7GB DVD, but in my experience a more realistic average is around 240 minutes (four hours!) I'm not sure what commercial DVDs use, if there is even a standard bitrate; I know those 'superbit' DVDs you see have a higher bitrate, achieved by sacrificing the extra space usually spent on commentaries and deleted scenes. I wouldn't be surprised if most commercial DVDs were around 7500kbps.

Also, in using my script, note that there are a couple additional formats supported by DVD that can help you get a lot more onto a single disc: 352x240 (Video CD resolution) and 352x480 (half-D1 resolution) are both supported by the DVD standard, as far as I can tell; if you have stuff taped from TV or low-quality movies, those resolutions might be better suited than the 720x480 standard DVD resolution, and could help you cut down on those bitrates (less resolution, less bitrate needed). I encoded a TV series to half-D1, and managed to get about 350 minutes per disc at 3600kbps, enough for seven or eight 45-minute episodes per DVD.

Good luck! Let me know if you have any problems with the script.

Thanks but I've decided to go for the DivX option and a new player for the living that can cope with that format.


At a bitrate of 2000 divx is about 1/4 the size of the DVD and you have to look REALLY close to see any difference in quality - and that means I can probably fit about 6 hours on a DVD-R


Simon