Video Asylum

Posted by Some Guy on March 14, 2003 at 12:51:16

In Reply to: downloading videos from the internet posted by paco on March 06, 2003 at 04:57:41:

there are four kinds of internet videos: mpg, avi, wmv and asf

Actually all of the above are MPG files for the most part, or at least all use MPG compression.

AVI stands for Audio/Video Interlace and is a generic term. As others have mentioned, the codec is far more important. One of the most inconvenient things is that this codec is generally not advertised, although there is a growing amount of software out there that will determine what codec has been used. You, of course, will then have to go find and install it. This usually means finding both the video and, now far more often, the audio codec as well.

The video codecs that are usually used are DivX 3 (still a great, solid codec), DivX 5 (totally different from DivX 3, not a replacement. Version 5.03 was recently released), XVID (a new open source that has great quality that just had a new version in February or so), and Indeo (an older, but still present codec). This is by no means a complete list (that could take hours) but these 4 make up a pretty big chunk of the whole.

The audio codecs are getting complicated. It used to be almost exclusively MP3, which didn't cause a problem. Now a lot of people are just using the AC3 stems directly from the DVD... yes, it's nice to have 5.1, but it can be a pain in the butt to decompress in some players. Personally, I downmix to MP3 and take the 2.0 instead. OGG VORBIS has been cropping up a lot lately, too. It's a good codec, but you need to find the Direct Show filters in some cases. There are also some people who suck you into using the WMA codecs... pheh!

MPG decompressors are built into most player software these days, but some versions (including VCD and SVCD implementations) are still problematic.

ASF and WMV are both Microsoft implementations and can usually be addressed by getting the latest Windows Media Player and codec sets... have they made a Mac version yet? I really don't know. I'm sure there are some codecs that let the Mac see them, though.

Of course there are a couple of other types... RAM and RM are used by RealMedia and about the only advantage is that it's pretty much cross platform. It can look pretty good, but it's not anywhere near as flexible or clean as the MPG codecs. Then there's the QT and MOV files... I'm pretty sure they're MPG as well, but they use the Sorenson codec. I'll say this about them... they usually look great, but the program QuickTime sucks on PC.

That's my little report. Hope it helps!