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added information about Dirac

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git-svn-id: file:///home/ksmith/gitmigration/svn/xmpp/trunk@3092 4b5297f7-1745-476d-ba37-a9c6900126ab
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Peter Saint-Andre 2009-04-23 23:26:04 +00:00
parent 6d554e93cd
commit aebfe0d7f0
1 changed files with 28 additions and 5 deletions
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xep-0266.xml
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@ -23,6 +23,12 @@
<shortname>N/A</shortname>
<discuss>jingle</discuss>
&stpeter;
<revision>
<version>0.2</version>
<date>2009-04-23</date>
<initials>psa</initials>
<remark><p>Added information about the Dirac video codec.</p></remark>
</revision>
<revision>
<version>0.1</version>
<date>2009-04-08</date>
@ -111,7 +117,7 @@
</section3>
</section2>
<section2 topic='Video' anchor='video'>
<section3 topic='Theora' anchor='audio-speex'>
<section3 topic='Theora' anchor='video-theora'>
<p>According to the theora.org website, the Theora codec is "a free and open video compression format". Theora is based on the VP3 codec originally developed by On2 Technologies and is now maintained by the <link url='http://www.xiph.org/'>Xiph.org Foundation</link>. The following table summarizes the available information about Theora.</p>
<table caption='Codec Considerations for Theora'>
<tr>
@ -123,12 +129,29 @@
<tr>
<td>Acceptable quality.</td>
<td>See &rtptheora;.</td>
<td>Freely downloadable under a revised BSD license at &lt;<link url='http://theora.org/'>http://theora.org/</link>&gt;; not yet commonly deployed, especially on devices that have deployed H.264 instead.</td>
<td>Freely downloadable under BSD license at &lt;<link url='http://theora.org/'>http://theora.org/</link>&gt;; not yet commonly deployed, especially on devices that have deployed H.264 instead.</td>
<td>On2's patents over VP3 were contributed to the Xiph.org Foundation in 2001.</td>
</tr>
</table>
</section3>
<section3 topic='H.264' anchor='audio-h264'>
<section3 topic='Dirac' anchor='video-dirac'>
<p>Dirac is a general-purpose video compression technology developed by the BBC that has been licensed in the open. It is used for everything from Internet streaming to HDTV. To date there is no RTP packetization deveintion for Dirac; however, such a format is under development.</p>
<table caption='Codec Considerations for Dirac'>
<tr>
<th>Quality</th>
<th>Packetization</th>
<th>Availability</th>
<th>Patents</th>
</tr>
<tr>
<td>High quality.</td>
<td>Not yet defined.</td>
<td>Freely downloadable under both GPL and LGPL at &lt;<link url='http://diracvideo.org/'>http://diracvideo.org/</link>&gt;; commonly deployed but not yet in video over IP systems because of the lack of an RTP packetization format.</td>
<td>Diract is patent-clear, and the BBC has allowed its related patents to lapse.</td>
</tr>
</table>
</section3>
<section3 topic='H.264' anchor='video-h264'>
<p>H.264 is a technology for video compression jointly designed by the ITU and the &ISO;. The following table summarizes the available information about H.264.</p>
<table caption='Codec Considerations for H.264'>
<tr>
@ -150,12 +173,12 @@
<section1 topic='Guidance for Implementors' anchor='guidance'>
<p>Given that both Speex and G.711 are patent-clear, freely implementable, and commonly deployed, this document suggests that implementors strongly consider including support for both codecs in audio applications of Jingle RTP sessions.</p>
<p>The situation regarding video codecs is more murky, and implementors face difficult tradeoffs. While Theora is patent-clear and freely implementable, it is not yet commonly deployed. On the other hand, deployment of H.264 is fairly common, but it is not patent-clear or freely implementable. For many open-source / free software projects and smaller technology vendors, implementation of H.264 is either impossible (because of patents and licensing restrictions) or prohibitively expensive (because of royalty payments). These developers are strongly encouraged to implement Theora and also to urge wider adoption of Theora among larger technology vendors. However, this document acknowledges that it may take some time before Theora is commonly deployed (especially on mobile devices) and that systems based on H.264 might be dominant in the marketplace for several years. This situation is unfortunate but cannot be directly changed by the XMPP developer community.</p>
<p>The situation regarding video codecs is more murky, and implementors face difficult tradeoffs. While Theora is patent-clear and freely implementable, it is not yet commonly deployed. While Dirac is patent-clear and deployed fairly widely, no RTP packetization format has been defined for it. While deployment of H.264 is fairly common, but it is not patent-clear or freely implementable. For many open-source / free software projects and smaller technology vendors, implementation of H.264 is either impossible (because of patents and licensing restrictions) or prohibitively expensive (because of royalty payments). These developers are strongly encouraged to implement Theora or Dirac and also to urge wider adoption of Theora and Dirac among larger technology vendors. However, this document acknowledges that it may take some time before Theora and Dirac are commonly deployed (especially on mobile devices) and that systems based on H.264 might be dominant in the marketplace for several years. This situation is unfortunate but cannot be directly changed by the XMPP developer community.</p>
</section1>
<section1 topic='Recommendations to the XSF' anchor='recommendations'>
<p>This document suggests that both Speex and G.711 could be recommended as mandatory-to-implement technologies for audio codecs, should the XSF decide to make such recommendations.</p>
<p>This document suggests that at this time it is not possible for the XSF to recommend a mandatory-to-implement technology for video codecs, but that it might be possible for the XSF to recommend Theora in the future if Theora is more widely adopted.</p>
<p>This document suggests that at this time it is not possible for the XSF to recommend a mandatory-to-implement technology for video codecs, but that it might be possible for the XSF to recommend Theora or Dirac in the future if they are more widely adopted.</p>
</section1>
<section1 topic='Security Considerations' anchor='security'>