Compression and File Size

[Meriadoc44]

I am very new to writing files to DVD. I have MyDvd by Sonic, it came with my Dell. For now that program will suffice. I have had no trouble making discs. Both Vcd and Dvd. The only issue I am having is if there is a way to maybe cut down on the amount of discs I am using for one file. I am using Virtual/Nan Dub to resize the file I have but I don't want to lose any quality when transfering to DVD and viewed on a TV. Of course the file is big. But 4 discs for a 2 hour movie is a bit much. The original file was 700mb. I resized it and recompressed it and now it is a little over a gig. The quality is excellent on a Televison. I guess my question is how much "quality" can I sacrafice to maybe shorten the file using Virtual Dub.

[DJ Bobo]

It is not possible to recompress to DVD format without quality loss, because MPEG-2 is a lossy compression format. However, the higher the bitrate, the less loss you get.

But I still don't understand why/how you need 4 (!!) discs for a 2h movie. This doesn't make any sense to me, since using the highest allowed bitrate, which is 10080kbps, you can put one hour on 1 DVD.

Second thing I don't understand: why VirtualDub when you're doing MPEG-2 video?! TMPG or CCE may be used for such things.

Anyway, considering that you wanna put a 2h movie on one single DVD, this will make 5000kbps for video and 192kbps for stereo audio.
Using 2-pass VBR encoding, you'll be able to minimize the quality loss (put min on 0 and max on 9800).
Encoding must be done in progressive mode, definitely! because interlaced reduces the compression efficency a lot.