Linked by Kroc Camen on Thu 29th Apr 2010 23:04 UTC
Internet Explorer I am almost flabbergasted by the spin and blunt-face upon which this news is delivered. We were just discussing the pot calling the kettle black with Apple / Adobe and now Microsoft have also come out in favour of a closed video format for an open web--IE9's HTML5 video support will allow H264 only. Update Now that the initial shock is over, I've rewritten the article to actually represent news rather than something on Twitter.
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Codec vs. format
by J. M. on Sat 1st May 2010 00:55 UTC
J. M.
Member since:
2005-07-24

The extremely widespread confusion of the words "codec" and "format" only leads to chronic misunderstanding. A codec encodes and decodes (hence the name). A format specifies how to make something that encodes and decodes. That's why H.264 is a format (it is a specification, as it does not encode or decode anything by itself). Or in other words - a codec standard (i.e. a standard for codecs - codec makers implement the specification in software or hardware).

That's also why Thom's article is incorrect in saying that Windows comes with a built-in DivX codec - DivX is a company and a brand name of proprietary products made by the company, such as the DivX Pro Codec, which is a software product, a codec, that encodes and decodes video in the MPEG-4 ASP format. So Windows comes with an MPEG-4 ASP decoder, a decoder for video in the MPEG-4 ASP format (that is, it can decode video made with any MPEG-4 ASP encoder like DivX, Xvid, FFmpeg MPEG-4 etc. - they all use the same format), not with the DivX software product made by the DivX company. It's like saying that "Mozilla released a new version of Microsoft Internet Explorer" or that Linus Torvalds started his own "Microsoft Windows" operating system in 1991. DivX is a registered trademark by DivX, Inc.

The failure to understand the difference between a software product and a format is also the reason why people are constantly confusing x264 with H.264 (there's no such thing as "x264 video"; x264 is just one of many software products that encode video in the H.264 format - it is a software encoder, and it does not decode video, so it's useful only for encoding), that's why people are confusing Ogg, Vorbis and Theora (three separate things), that's why people think they must use the same codec the audio/video was encoded with for decoding (ignoring the whole point of common standards - i.e. multiple compatible implementations for the same format), that's why people are confusing free software with open standards, or copyright with patents (for example, some people believe that because Xvid is free, it is also patent-free and therefore suitable for the web - of course it uses the patented MPEG-4 format just like everyone else), and so on and so on.

So it's very useful to understand the difference between a company, format and a software product. Because it is impossible to understand the whole issue without understanding the basic terms.

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