MozzilaMy LCA talk on Friday was about why open video is critically important to free software, and what Mozilla is doing about (plus a discussion of the relationship between Web standards and free software in general). Little did I know that Youtube and Vimeo would pick the day before my talk to cast a glaring spotlight on the issue!

Youtube and Vimeo have started offering video playback using the HTML5 <video> element. That is good news for free software, since it means you don’t need a closed-source Flash player to play the video [1]. However, they only offer video in H.264 format, and that is not good news for free software. A lot of people have noticed that Firefox doesn’t support H.264, and apparently many people don’t understand why, or know what the problems are with H.264. This is a good time to restate the facts and re-explain why Firefox does not support H.264. I’ll be mostly recapitulating the relevant chunks of my talk. (Hopefully a full recording of my talk will become available from the LCA site next week.)

The basic problem is simple: H.264 is encumbered by patents whose licensing is actively pursued by the MPEG-LA. If you distribute H.264 codecs in a jurisdiction where software patents are enforceable, and you haven’t paid the MPEG-LA for a patent license, you are at risk of being sued.

So why doesn’t Mozilla just license H.264 (like everybody else)? One big reason is that that would violate principles of free software that we strongly believe in. In particular, we believe that downstream recipients of our code should be able to modify and redistribute it without losing any functionality. This is freedom that copyleft licenses such as the GPL and LGPL (which we use for our code) are intended to ensure. It is possible to obtain patent licenses in a way which works around the letter of the GPLv2 and LGPLv2, but honoring the letter while violating the spirit is not a game we are interested in playing. Continue reading.