Movie Download Quality

Movie Download
This may be a silly question but here goes. Most of the movies available for download are between 600 and 800 MB for a 2 hour film. On a DVD that would be 3 - 4 GB. I know they may be compressed but is this full DVD quality? It's hard to tell on my crappy laptop screen what quality they are but they seem a little fuzzy. Is there a particular file varient which is most likely to yield higher quality? Secondly how come there are so many versions of films with chinese/japanese subtitles and how can they be avoided? Thanks,
Niall.

p.s. One other thing - when I start to burn DVDs will these downloads support surround sound on my home theatre system just as a normal DVD would?

[Cenwag]

All compressions are necessarily "lossy".
The less loss, the higher the quality but the bigger the file - exponentially!

They are therefore not the full DVD quality.

Quality is also determined by the compression algorithm used in the software to compress the original movie.

It's like anything else: You get what you pay for, if you don't pay, you just have to wear what's offered.

China and Japan lead the world in piracy, that's the reason for the subtitles.

In regards to surround-sound - see paragraph 4.

[Lord of the Rings]

Just in addition. Most commercial dvd's use dvd9 format which holds around 8 GB not the dvd 5 format that holds about 4.4 gb. So what you're dwnlding has probably been decreased in size by b/w 1/5th to 1/10th of the original size. I've heard that some of these are still quite reasonable in quality depending on the softw utility/codecs & skills used.

[Jcuzzo22]

I Find that downloading video files that are in two parts such as: bla.bla.cd1, bla.bla.cd2 usually are much better quality then single files only 700mb. But what the others say are true after a movie is compressed it will lose a lot of quality.