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Last Updated: Friday, 30 March 2007, 12:53 GMT 13:53 UK
Tiny files set for a big future
Ian Hardy
By Ian Hardy
Click's North America technology correspondent

A lot of technologies have conspired to make it easier for us to capture and share images and video on the web and with our friends and family. One of the most unsung is compression but without that there would be no photos on the web, movies on DVD or digital TV.

DVD player
DVDs are encoded in Mpeg 2

Songs, photographs, movies and video clips are all compressed into small files using complex mathematical algorithms or codecs that strip away much of the original information, yet retain enough quality for us not to notice, ideally.

In the video world, constantly improving codecs, and the proliferation of software and hardware with built-in compression technologies, is one reason video is seemingly everywhere.

DivX is one of the most popular codecs and, like many others, is lossy. This means that during the encoding process you lose bits of information to reduce the size of the squashed file.

By contrast some codecs are lossless. For instance creating a Zip file means no data is lost even though the final file size will be smaller than the original.

DivX is already popular in Europe but is now gaining a foothold in the US thanks to its combination of small file sizes and high quality images.

"We get 25 frames in every second," explained Mark Lawson from DivX. "We look at each of those frames and the stuff that doesn't change, that isn't moving, we can do stuff with that to make it smaller because we don't need to replicate the data again.

"So you go through every frame and allow the stuff that's moving to go through, while the stuff that isn't moving you compress it down to make it smaller."

Encoding and decoding video is a complex process with many factors such as bit rate and frame rate to take into account, but increasingly companies are encouraging the consumer to take charge with new technologies that attempt to hide the complexities.

"The goal is to make video compression as invisible to the end-user as possible. But it's very important because it improves both the efficiency of transport as well as the quality of playback," said Eric Ameres from compression firm On2 Technologies.

"You want to have the best quality, the highest resolution and the best user experience while consuming the least resources from the service provider's perspective."

Hardware or software?

There are already many devices that make encoding video a real-time one-click operation that is computer free.

The iRecord media recorder is a slim white box that uses the H.264 codec to produce portable video from any source, including DVD players. Plextor's ConvertX encoding device does a similar thing using Mpeg 4,1 and 2.

Then there is the Video To-Go USB stick that claims to re-encode movie files at five times real-time via a built-in dedicated video processor chip.

"The Video To-Go is using hardware encoding," said Mike McCoy from ADS Technologies, the company that makes the device. "We see the biggest benefits in time savings, and that's really what we're doing here - saving time in bigger files.

Mini DV
Keeping copies on multiple formats will help preserve your video

"So if we had a 5GB file it might take an hour and a half or two hours with software encoding, but with hardware encoding it can be finished in 15 or 20 minutes."

But hardware does not have it all its own way, advanced video compression is being starting to appear in a slew of software titles. The newest version of Toast not only burns DVDs on Macs - its original function - but can now transform high-quality video into multiple formats for multiple uses. It is the default application for moving Tivo shows from the DVR to portable players or DVDs.

For Windows PC's Nero has done something similar, expanding its video compression capabilities and offering an Mpeg 4 compatible codec called Nero Digital that claims to reduce video files to 20% of their original size whilst maintaining a high quality result.

So why is any of this interesting? Well, if you save your home movies using a specific codec, how do you know that in a few years from now you will be able to see them or play them?

Craig Campbell from Nero said he was not too concerned about the codecs: "I'm pretty sure it's going to be the hardware that's the problem. They need to support both old and new codecs. That's a lot of work and expense and the manufacturers just don't want to pay that."

So how can you be sure to preserve your treasured memories?

There's no 100% guaranteed solution for longevity but probably the best advice is to keep copies in at least two formats such as Mpeg 2, that is commonly used with DVDs, and on a tape format, such as Mini DV.

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