Next generation of compression

It's always amazing to me, how we continue to use some of our excess computing cycles to cram more into less using ever-better compression

technology. And now, we can experience the fruits of the next-generation of compression, MPEG4, in an easily available beta

implementation of Microsoft's Windows Media Player. 

With thanks to readers Michael Engel and Eric Larson for bringing this to our attention, Microsoft's Windows Media 8 beta packs `near-CD'

quality audio into 48 KBPS of data. Doing the math, this translates into being able to store one hour of pretty high quality audio in 21.6 megabytes of storage. That means that a 32-megabyte pocket player equipped to play these files could serenade us with 1.5 hours of audio. Full CD-quality audio can be encoded at 64 kilobits/second.

One interesting spin-off of this technology is a new Microsoft/Kenwood pocket CD player, due in the middle of this year, that will hold 22 hours of music at full CD quality--it's not storing this data on a large hard drive, but on a CD! 

(The trick is that you encode the MPEG4 files on your PC, burn those encoded files onto a CD, and then pop it into a CD player that understands this new format--voila, enough music to last for an around-the-world flight!)

Neat. But MPEG4 compression isn't just about audio; it can be applied to video as well. Microsoft says that they can provide `near-VHS' quality video at 250 KBPS (31.25 KBPS), which translates to being able to store a one-hour move in only 112.5 megabytes. `Near-DVD' quality video, they say, can be stored in twice that amount of storage, or transmitted down a 62.5 KBPS pipe (well within the capabilities of most broadband connections). And this technology supports even higher quality formats (at higher bandwidth), as well.

I don't have a good enough `ear' to critically listen to the music clips, but I did view some of the videos at the link above. (If you have Windows Media Player, it will automatically request the new decompressor it needs--nicely done.) Looking at the `near-VHS' clips, the result was surprisingly good. At the video's default (small) size, there was little pixelization and few artifacts, and the playback was usually very smooth.

Sometimes, though (I suspect because there were lots of people sipping at the video server's straw), the data rate dropped to about half it's normal 31 KBPS, yet even then the presentation degraded nicely, falling back to a series of still images that seemed to stay in sync with the audio (which never faltered.)

Expanding the video size to 200 percent, however, did significantly reduce the quality. Of course, I then just had to try the `near-DVD' version. Its default image size was larger, and at 100 percent, it was beautiful. Not quite perfect, as I did see a few artifacts when the entire scene changed radically, but it turned in a very impressive performance at 62.5 KBPS (500 kilobit/second, still well within the capabilities of many broadband connections.)

Did I try the 93.75 KBPS (750 kilobits/second) version of `near-DVD?' You bet. Its image size, in letterbox format, was too wide for the full-screen Windows Media Player, and the video looked wonderful. I can't say it was as good as a DVD, but especially in `full screen' mode, if the Internet had been uncongested enough to allow the data to stream at its full speed, this video would have been a most impressive demonstration of what is now possible. (In this case, due to the congestion, instead of playing it in real time, Windows Media Player buffered the movie extensively and then played it for me.)

Microsoft wasn't the only one recently demonstrating better multimedia compression. For example, PacketVideo and SolidStreaming are both using MPEG4 technology which, they say, can provide video `at bit rates as low as 9.6' kilobits/second, to bring video to pocket cell phones!

The MPEG4 video I saw was not perfect even at broadband speeds, and it would clearly have significant limitations at pocket phone speeds. But what I saw is certainly `good enough' for many purposes, including casual viewing. For example, how about a late night `I'd really like

to see that movie' rental via video-on-demand over the Internet? 

Mixing these compression techniques with the growing number of broadband connections suddenly makes this very feasible!

Might we be seeing the first nails in the coffin of the videotape/DVD rental industry?

Jeffrey Harrow


Senior Consulting Engineer


(Technology and Corporate Development Group), Compaq


Note: This is an article from the `Rapidly Changing Face of Computing', a free weekly multimedia technology journal written by Jeffrey Harrow. More discussions around the innovations and trends of contemporary computing and the technologies that drive them are available at

www.compaq.com/rcfoc. The writer's opinions do not necessarily reflect the opinion of Compaq. The RCFoC is copyright 2000, Compaq.