On 27/05/07, Ivo Emanuel Gonçalves <[EMAIL PROTECTED]> wrote:
Hello all,
Hi Ivo,
Section 3.14.7.1. of the HTML 5 specification (regarding the <video> element) recommends that user-agents should suport both Theora and Vorbis. This, I believe, is a great idea for interoperability between the different platforms out there, to make sure that <video> will work on as many user-agents as possible.
Yes, it's very important to have a baseline video codec that's supported everywhere, just like JPEG and PNG image formats are supported everywhere.
I would like to propose that section 3.14.8.1, regarding the <audio> element, be changed to recommend that user-agents should support the Speex voice codec, as Speex seems perfectly suited for podcasts, as well as for pages read aloud. These situations seem to be one of/the aim of the <audio> element, hence it appears that Speex, due to its quality, patent-free status, open specification, and architecture reflecting the needs of the Internet seems to be the natural choice for interoperability of the <audio> element.
That's a great idea. So, the three main open source and patent-free audio codecs (ie. developed in a documented manner that avoids patent encumberances by using known-free algorithms) are: Speex (http://www.speex.org/) -- low bitrate speech-quality codec Vorbis (http://www.vorbis.com/) -- music codec (similar to MP3, widely supported on hardware devices). FLAC (http://flac.sf.net/) -- lossless, compressed audio (CD quality) It would be interesting to allow use of any of these, but in particular Speex and Vorbis as they provide useful compression for streaming. These codecs have standard mappings into the Ogg container, as used by Ogg Theora (the standard video codec). So, it could simplify things to harmonize the audio codec recommendations for both video and audio, to include these audio profiles. As an implementation note, the oggplay plugin for Firefox currently supports Theora with either Vorbis or Speex as the audio codec. cheers, Conrad.
