Video and audio: playing media in the browser - HTML5 in Action - page 353

Supporters of h.264 argue that Ogg/Theora is technically lower quality, has no hardware
support (important on battery-powered devices with low-end CPUs), and is more at risk
from patent trolls because the obvious way to make money out of infringers is to sue them,
whereas submarine patents affecting h.264 can be monetized through MPEG LA.
Supporters of Ogg/Theora argue that the openness of the web requires an open video
format. Mozilla couldn't distribute its source code if it contained an h.264 decoder because
then everyone who downloaded the code would require a license from MPEG LA. Google
avoided this issue by splitting its browser into free parts (the open source Chromium pro-
ject) and closed parts.
Because the vendors were divided on which format to make standard, and because one
of the goals of HTML5 is to document the reality of the implementation, the requirement
for supporting any particular codec was removed from the specification. This isn't without
precedent in the HTML world—the <img> element doesn't specify which image formats
should be supported. We can see some light at the end of the tunnel: Google subsequently
released the WebM format as open source with an open license. As the owner of the
number-one video site on the web, YouTube, and a provider of the Android mobile OS, it's
well-positioned to overcome h.264's commercial advantages.
8.3.2. Converting between media formats
For practical purposes, what you need to know is how to convert a video in one of the sup-
ported formats to a different format. A tool called a transcoder can convert between dif-
ferent container formats and encodings. There are several online and downloadable tools
that convert individual media files; several are listed in the links and resources in appendix
J . But for batch processing large numbers of files you'll need to use a command-line tool.
Appendix H explains how to use ffmpeg to transcode the video files used in this chapter.
You're at the point where you can play a video in every browser that supports the
<video> element, thanks to the <source> element. You also know which video formats
you need to provide to support which browsers. Now it's time to create the telestrator fea-
ture, which will let you draw directly onto the playing video.