DVDShrink?

[Andy149]

I have used dvdshrink on two dvd's now with great results i cant fault it and i am stumbled on how it manages to compress the video at such a fast rate its amazing! anyone know how this works because itsa to fat to re-render it and i cant see any tale tell signs opf compression (ie a bad divx blocky encode etc)

[Vejita-sama]

There are two types of 'compression' out there. Encodes and transcoders. IC (instant copy) is the only re-encoder that I know of. DVD2One, DVD Shrink and the rest are transcoders. From doom9.org:

"Recently, compressed domain transcoders have reached quite some popularity. These transcoders are based on algorithms designed to recompress an MPEG-2 stream in real-time for TV broadcast. These programs can transcode an entire DVD movies in only a few minutes, because they do not have to decode and re-encode the entire video stream, but only part of it. I will not go into a detailed explanation of the mechanisms used as they are quite involved but basically what you get is a size (and hence quality) reduction per time unit that cannot be rivaled by regular MPEG-2 encoders (though the latter category can yield better quality). DVD2One was the first program to be based on these principles, now DVD Shrink is the first free program to offer this functionality."

Transcoders ALWAYS give worst quaility then re-encoding. However, not everyone can see that difference. Some people claim that >5% compression in DVD shrink the picture goes to crap, others say >25%, while others >50%. Partly it depends on your setup (55" widescreen plasma vs. 20" tube) and how well you know where and what to look for.

In the end, thou it's a personal choice. If you like the quaility of DVD shrink then great, keep using it. If you don't then don't.