What codec does DVD Shrink use to compress movies?

[Leander]

DVD Shrink is probably my favorite tool for backing up movies, it's quick, painless and very simple to use. However it is'nt quite perfect because when it compresses movies at times it can signficantly reduce the video quality.

I'm just curious if anyone here has experimented with replacing the codecs Shrink uses with some other one. (if that's even possible) XVID for example would be cool if it could be used in Shrink although I'm not sure if the program would still retain it's speed factor. Anyone ever given thought to this idea before?

Also why is it the movie industry does'nt use more efficient compression standards? If Hollywood used codecs like XVID instead of spreading a TV series out over 5-7 disks they could probably do it in 2-3, therefore saving them money and time.

[jtoolman2000]

It might be a built in proprietary Transcoder. It is not a Codec or Encoder. I also do not believe that it can access and use anything else that might reside in your computer.

[lordsmurf]

There is no codec involved. It's mathematical adjustments to the MPEG quanta.
Read this: http://www.hpl.hp.com/personal/Susie_Wee/PAPERS/hpidc97/hpidc97.html


UPDATE (4/2010):
Because the HP link is now dead, I've mirrored the article here: How Transcoding MPEG Video (DVD Shrinking) Works
See http://www.digitalFAQ.com/forum/showthread.php/transcoding-mpeg-video-2177.html
This info is too interesting to just disappear and be lost in the void that is the internet.

[garrisonkw]

To be a DVD-Video, and therefore play on all DVD players, a disc's video must adhere to strict requirements. One of those requirements is that the video be encoded using the MPEG-2 standard. XviD is provides for smaller file sizes, but you wouldn't end up with a DVD that could play in most players.

The movie industry also has to pick something and run with it for years until they're ready to change to something new. Imagine if you have to buy a new DVD player every 6 months to play the latest batch of discs. People would quit buying movies altogether as it would be entirely too frustrating. A side effect is that as time moves on, the currently used technology (MPEG-2) becomes slightly out of date.

[greymalkin]

also the idea here is usually to put the movie back on a dvd+/-r, so using xvid/divx, (insert compression algorithm here), etc. would not be an option. Also, if you actually did re-encode it wouldn't be the quick and painless process you were praising shrink for. Theres got to be a compromise somewhere, but for the speed of the application, I think it does a great job of getting the size down in the time it does with as little image deterioration as it does.

doh! i see 2 posts popped up between when i started replying and posted my reply. sorry if some of the information in my post is redundant.

[lordsmurf]

A side effect is that as time moves on, the currently used technology (MPEG-2) becomes slightly out of date.

MPEG-2 is not even remotely out of date. Most people think MPEG-2 is limited to MP@ML specs. But check this out...

MP@HL1440
(Main Profile@High 1440 Level) 60Mbps, but currently limited to 25Mbps to fit on DV tape 1080i with 1440 pixels/line at [up to] 30fps, 1080p with 1440 pixels/line at [up to] 30fps

MP@HL
(Main Profile@High Level) 60Mbps 1920x1080 at 30 frames/sec OR 1280x720 at [up to] 60fps

422P@HL
(High Profile@High Level / 4:2:2 Profile@High Level) 100Mbps 1080i with 1920 pixels/line at [up to] 30fps, or 1080p with 1920 pixels/line at [up to] 60fps (!) 4:2:2

The only thing holding back this (or ANY other competitor for that matter) is simply a lack of resources to handle this much data per second. CPUs, RAM and storage is only now getting to where it can be used. MPEG-2 easily has some of the highest quality, it's just not the smallest anymore. But you return to the old space/performance war, which is more important? Compression or quality?

Those that think XVID is going to take over the video market are honestly just dreaming an amatuer hobbyist dream.

[garrisonkw]

Good point. I wasn't specific enough. I was referring to the specs used on current DVDs.