The HTML5 specification introduced the video element for the purpose of playing videos, partially replacing the object element. HTML5 video is intended by its creators to become the new standard way to show video on the web without plugins, instead of the previous de facto standard of using the proprietary Adobe Flash plugin, but has been hampered by lack of agreement as to which video coding formats should be supported in web browsers.
Supported video formats
The HTML5 specification does not specify which video formats browsers should support. User agents are free to support any video formats they feel are appropriate, but content authors cannot assume that any video will be accessible by all complying user agents, since user agents have no minimal set of video formats to support.
The HTML5 Working Group considered it desirable to specify at least one video format which all user agents (browsers) should support. The ideal format in this regard would:
Have good compression, good image quality, and low decode processor use.
In addition to software decoders, a hardware video decoder should exist for the format, as many embedded processors do not have the performance to decode video.
Initially, Ogg Theora was the recommended standard video format in HTML5, because it was not affected by any known patents. But on December 10, 2007, the HTML5 specification was updated,replacing the reference to concrete formats:
User agents should support Theora video and Vorbis audio, as well as the Ogg container format.
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It would be helpful for interoperability if all browsers could support the same codecs. However, there are no known codecs that satisfy all the current players: we need a codec that is known to not require per-unit or per-distributor licensing, that is compatible with the open source development model, that is of sufficient quality as to be usable, and that is not an additional submarine patent risk for large companies. This is an ongoing issue and this section will be updated once more information is available.
The result has been the polarisation of HTML5 video between industry-standard, ISO-defined but patented formats, and free, open formats.