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This article appeared in the July 2001 issue of the Louisville Computer News. It was written by Lee Larson.
Ages ago in Internet time--that's about three years in people time--there were dozens of different sound formats floating around, and it was a real nuisance. After downloading a sound file, the next step was figuring out which program could play it. Some of the common formats included Amiga IFF, Sun µ-LAW, SoundEdit, Sound Blaster VOC, and about a half dozen others. The indispensable tool was SoundApp, which converts sound files between every format known to man or beast (www-cs-students.stanford.edu/~franke/SoundApp/).
Then, MPEG I Layer 3, usually called just MP3, swept away all the confusion by becoming an almost universal standard. After the acceptance of MP3, sound exploded on the 'Net, and we've been following the fights between MP3.com, Napster and the RIAA ever since.
All this was brought to mind by a message that floated into my e-mail box a few days ago. It contained the question "How do I play AVI movies on my Mac?" It would be nice if there were a simple answer to this question, but there isn't. Video on the 'Net is in a worse state of confusion than sound was in a few years ago.
The AVI extension is used with Microsoft's Video for Windows, the video architecture built into Windows 95. It has since been pretty much abandoned by Microsoft, which now uses the Windows Media Technologies. Windows Media videos usually have the ASF extension. Its big competition is Apple's QuickTime format, with file extension MOV.
Knowing that you have an AVI file is only half the fun. Just like QuickTime, Video for Windows is an architecture, not an explicit file format. A file with an AVI extension is sort of like a can of soup without a label. You have to open the can to see what's in it. There are many different ways to pack the sound and pictures inside the can, and there's no universal way to play them back.
This brings us to the subject of codecs. The type of codec determines what kind of soup is sealed in the can.
The word codec is a lazy way of naming a program that codes and decodes data. Most codecs are designed to compress audio or video into as small a package as possible without losing too much quality. There are many trade-offs possible, depending on whether you want such things as speed of compression, accurate playback, small files, or portability between different types of playback machines. Video codecs are usually pretty slow at compression, as is well-known to anyone who's exported from iMovie to QuickTime.
Microsoft included several video codecs with Windows 95, including Cinepak, Indeo 3.2 and IMA. Intel added Indeo video 4 and 5. The DivX codec is more recent, and has become an open source product. MPEG1, MPEG2 and MPEG4 are also possibilities.
QuickTime Player can be coerced to show most AVI files using the standard codecs, but you may be forced to hunt down a plug-in. To see what's needed, do the following:
o Open the file in QuickTime Player.
o Choose Get Movie Properties from the Movie menu.
o Choose Video Track from the left pop-up menu in the Properties window.
o Choose Format from the right pop-up menu.
The Data Format field will show which codec was used.
For example, the data format might be Indeo Video, a codec that doesn't come with the standard QuickTime installation. There are several different generations of Indeo Video, and Apple has three plug-ins available on its software update Web site (www.apple.com/swupdates): Indeo Video 3, Indeo Video 4 and Indeo Video 5. If you need Indeo Video, you might as well download all three and install them because they don't conflict with each other, and each works with a different generation of the Indeo file format. Then you'll be ready for any of the Indeo formats.
QuickTime 5 supports Cinepak and MPEG1 in the standard installation, so neither of those should be a problem.
And that brings us to DivX.
There are many people who think DivX will do for video what MP3 has done for audio. Created by Jerome Rota of France and Max Morice of Germany, DivX combines MPEG4 audio compression with MP3 sound compression to yield near-DVD quality output from amazingly small files. Using DivX compression, an entire five gigabyte DVD movie can be compressed to under 600 megabytes. This is still a big file, but anyone with a good broadband connection to the Internet can download it in a couple of hours and burn it onto a CD to watch again and again.
The reason MP3 caught on for sound was that it made the large, high-quality music on compact disks small enough to trade over standard modem connections. DivX makes it possible to do the same thing with entire movies over broadband connections. If you know where to look on the Internet, you can find all the latest DVD releases in DivX form free for the taking. For example, searching for the key "divx" in my favorite Gnutella client brought up dozens of movies and TV programs.
All this is making the movie industry's trade association, the MPAA, very nervous. They've already filed suit against several Web sites offering software such as DeCSS which bypasses the copy protection on DVDs, making it possible to compress them into DivX format. After all their legal wrangling, it's still really easy to find programs like DeCSS on the Web (www.videolan.org).
The original DivX code used the MPEG4 codec included with the Windows Media Player, so it was not a truly free and open codec. The home of DivX development is now the OpenDivX section of Project Mayo (www.projectmayo.com), where a completely open source version of DivX is being developed. They already have an open source MPEG4 decoder.
A Macintosh DivX Player can be downloaded from www.mac.st. It still uses the Microsoft MPEG4 codec from Windows Media Player. But, it can only access the codec from Windows Media Player 6.3 for Macintosh, not the newer WMP version 7. Be sure to read the documentation carefully because some files need to be doctored before they can be played. After some tinkering, it does work fine, and is even compatible with Mac OS X
Another question that keeps coming up is "What's the best Gnutella client for the Mac?" My answer is that there probably isn't one; they all have different problems. Under Mac OS 9.1, there are three choices: Mactella, LimeWire and Furi. Phex is an update to Furi that only runs under Mac OS X because it requires Java 2.
Furi is presently moribund; it hasn't been updated in well over a year.
LimeWire is a Java program running on several different platforms. When it works, it works well. Particularly nice is the way it groups multiple instances of the same file together and repeatedly tries to download files from among all those offering it. On the down side, there is some sort of annoying bug that causes it to occasionally seem as though the machine has locked up. It eventually plods its way through whatever causes the stall, but this makes working on anything else while LimeWire runs in the background very tedious.
Mactella is fast and works well in the background, but it lacks some of the nice touches built into LimeWire. For example, LimeWire has an option to limit the amount of bandwidth the program uses and Mactella does not. Mactella doesn't group like files together, or repeatedly attempt to download them when the first attempt fails.
The latest versions of all the Mac Gnutella clients can be found at the Gnutelliums site (www.gnutelliums.com/mac). There are also active support forums for each client at the site.
The speaker at the July LCS meeting will be Harry Jacobson-Beyer. He will demonstrate Internet web sites that allow users to store, and share digital photos with friends and family.
The Louisville Computer Society meets on the fourth Tuesday of the month from 7:00-9:00 P.M. at Pitt Academy, 4605 Poplar Level Road, at the intersection of Poplar Level Road and Gilmore Lane. Everyone is welcome to attend. For more information, on the Web go to www.aye.net/~lcs, or e-mail lcs@aye.net.
The LCS also sponsors an e-mail discussion list devoted to Macintosh topics. To join, send e-mail containing only the words "subscribe macgroup" to majordomo@erdos.math.louisville.edu.
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