What type of compression do all these programmes like clone etc use?

[djjaimeb]

What type of compression do all these programmes like clone etc use. As we all know DVD is mpeg2, and i also know that when movies are crushed down to fit on a 4.7GB disc you reduce the quality. But what type of compression is used to do this?


Nice 1

 

[LTR12101B]

MPEG2, but at lower quality - just like MP3 can be at different bitrates.

I really don't understand the details of how they do it without fully re-encoding, but the method is faster, but does lose out to a full re-encode on quality at deeper shrink levels.

Instant Copy apparently uses a slower but better method

 

[celtic_druid]

They are all transcoders. If you want to know how it works I guess you could download and have a look at the source of M2VRequant or ReJig (uses M2VRequant as its engine). Although that is just one implimentation.