# Movielink and Video Compression **URL:** \ **Category:** Factual Questions\ **Created:** [August 10, 2003, 4:24am UTC](https://boards.straightdope.com/t/movielink-and-video-compression/194145 "2003-08-10T04:24:52Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![ricksummon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ricksummon/32/3333_2.png) [@ricksummon](https://boards.straightdope.com/u/ricksummon)\ **Post date:** [August 10, 2003, 4:24am UTC](https://boards.straightdope.com/t/movielink-and-video-compression/194145/1 "2003-08-10T04:24:52Z")
There’s a new video-on-demand rental service called [Movielink](http://www.movielink.com/) that lets you watch movies on your computer. Instead of streaming, the movie is downloaded completely before you watch it. I downloaded Cowboy Bebop: The Movie from them, and the video quality was very good, if not quite up to DVD standards. However, the movie is only 695 kbps! How is it possible to compress full-motion video and audio at that degree of quality with such a low bit rate? ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [August 10, 2003, 7:05am UTC](https://boards.straightdope.com/t/movielink-and-video-compression/194145/2 "2003-08-10T07:05:31Z")
Ummm…kbps is a _rate_ of data transfer, not a file size. Did you mean 695 k? Do you have a cable modem? That’s easily within the range of a typical cable setup. I don’t think it’s at all possible to have a full movie only occupying 695 k. ---
**Author:** ![II\_Gyan\_II](https://avatars.discourse-cdn.com/v4/letter/i/bbe5ce/32.png) [@II\_Gyan\_II](https://boards.straightdope.com/u/II_Gyan_II)\ **Post date:** [August 10, 2003, 7:12am UTC](https://boards.straightdope.com/t/movielink-and-video-compression/194145/3 "2003-08-10T07:12:29Z")
**Q.E.D.** In this case, it could mean that _each_ second of film takes up 695 kilo_bits_ (b, not B). That works out to 600MB/2hr movie. That’s DivX-sized. ---
**Author:** ![Rex\_Fenestrarum](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rex_fenestrarum/32/7265_2.png) [@Rex\_Fenestrarum](https://boards.straightdope.com/u/Rex_Fenestrarum)\ **Post date:** [August 10, 2003, 1:55pm UTC](https://boards.straightdope.com/t/movielink-and-video-compression/194145/4 "2003-08-10T13:55:32Z")
Yes, he’s talking about kilobits. Larger data rates = bigger file sizes, which is why a 256kbps MP3 is twice as big kilobyte-wize as a 128kbps one. ---
**Author:** ![robcaro](https://avatars.discourse-cdn.com/v4/letter/r/df705f/32.png) [@robcaro](https://boards.straightdope.com/u/robcaro)\ **Post date:** [August 10, 2003, 3:14pm UTC](https://boards.straightdope.com/t/movielink-and-video-compression/194145/5 "2003-08-10T15:14:38Z")
Unfortunately, I cannot download a movie from that site. I live outside of the USA and they don’t allow downloads here. Too bad because I would like to participate in watching movies on-line, at any speed. ---
**Author:** ![BKABBY](https://avatars.discourse-cdn.com/v4/letter/b/3ab097/32.png) [@BKABBY](https://boards.straightdope.com/u/BKABBY)\ **Post date:** [August 10, 2003, 4:42pm UTC](https://boards.straightdope.com/t/movielink-and-video-compression/194145/6 "2003-08-10T16:42:14Z")
695kbps is actually pretty good. When I stream video from websites, it’s either 100kbps (not so good) or 300kbps (sounds just about like normal TV, looks a bit fuzzy, but still good). Highest I’ve ever seen was 500kbps, which my DSL couldn’t really stream that well, so, it was choppy, but when it was going it looked almost normal. I would think 695kbps would defintely be good quality. ---
**Author:** ![ricksummon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ricksummon/32/3333_2.png) [@ricksummon](https://boards.straightdope.com/u/ricksummon)\ **Post date:** [August 10, 2003, 6:53pm UTC](https://boards.straightdope.com/t/movielink-and-video-compression/194145/7 "2003-08-10T18:53:12Z")
What I’m saying is that a DVD has an average bit rate of 4-5 Mbps and this is about 1/6th of that. How is it possible to get such high compression without losing much quality? I mean, a CD-quality MP3 file is 128 kbps for the audio alone! Surely the video must be more information-dense. ---
**Author:** ![II\_Gyan\_II](https://avatars.discourse-cdn.com/v4/letter/i/bbe5ce/32.png) [@II\_Gyan\_II](https://boards.straightdope.com/u/II_Gyan_II)\ **Post date:** [August 11, 2003, 5:52am UTC](https://boards.straightdope.com/t/movielink-and-video-compression/194145/8 "2003-08-11T05:52:45Z")
> [@](#): > > \*Originally posted by ricksummon \* > **How is it possible to get such high compression without losing much quality?** That’s what I meant with my “DivX-sized” comment! Check out some DivX compressed files: (download a free codec/player from [here](http://www.divx.com/divx/)) [Trailers in DivX](http://www.divx-digital.com/modules.php?name=Encyclopedia) On this page, the Signs trailer is encoded at 243 kbps. ---
**Author:** ![Alereon](https://avatars.discourse-cdn.com/v4/letter/a/ecd19e/32.png) [@Alereon](https://boards.straightdope.com/u/Alereon)\ **Post date:** [August 11, 2003, 6:48am UTC](https://boards.straightdope.com/t/movielink-and-video-compression/194145/9 "2003-08-11T06:48:10Z")
Modern video compression really is a LOT better than that used in DVDs. Additionally, the bitrate used in DVD is dramatic overkill most of the time. It’s designed so that even the highest action scene will still look good, which means that most of the time you’re wasting a lot of space. If you’re not actually streaming the movie, you can take advantage of Variable BitRate, which allows you to use a higher bitrate for high-motion scenes and a much lower bitrate for static scenes. This, combined with an improved video compression technology such as MPEG4 (the kind of compression used in DivX), and perhaps some filtering to improve compressibility, would easily allow near-DVD-quality video to be fit into a very small amount of space. As for the audio, using Advanced Audio Coding (AAC) it’s quite possible to cram surround sound into a quarter of the bitrate used in DVDs. If you only want stereo, you can compress it further, down to probably around 80kbps without noticeable quality loss.