media:

仕様書

[1] Media RSS Specification (2016-03-19 01:12:36 +09:00 版) <http://www.rssboard.org/media-rss>

名前空間URL

[16] 公式には http://search.yahoo.com/mrss/ とされています。

[17] 巷には http://search.yahoo.com/mrss を使ったフィードもあるようです。そちらを使った実装もありますし、 Google Books によれば複数の書籍でそちらを使って解説しています。

メモ

[2] Media RSS Specification (2016-03-19 01:12:54 +09:00 版) <http://www.rssboard.org/media-rss>

Media RSS Specification, Version 1.5.1
Editor's Note: This is a draft document that is still being proofread during the transition of Media RSS from Yahoo to the RSS Advisory Board. The official specification is at http://video.search.yahoo.com/mrss until this notice has been removed. This is version 1.5.1 of the Media RSS specification, a namespace for RSS 2.0 published on Dec. 11, 2009.

[3] >>2 といっているが、そのリンク先の本家が消滅して久しい。 2016-03-18T16:13:17.000Z

[4] media:thumbnail は未だにたまに使われますが、それ以外は見かけません。 2016-03-18T16:14:32.600Z

[5] (2016-03-19 17:07:25 +09:00 版) <https://sourceforge.net/projects/sparkylinux/rss?path=/>

<media:content xmlns:media="http://video.search.yahoo.com/mrss/" type="application/pgp-signature; charset=us-ascii" url="https://sourceforge.net/projects/sparkylinux/files/testing/sparkylinux-4.3-dev2-i686-minimalcli.iso.sig/download" filesize="473"><media:hash algo="md5">b21b4574e171a6750804e509f9bdc7b5</media:hash></media:content>

[6] BitTorrent.org (Arvid Norberg <arvid@bittorrent.com> 著, 2014-09-29 05:34:53 +09:00 版) <http://www.bittorrent.org/beps/bep_0036.html>

media:content
The media content tag is really the "content" tag under the namespace http://search.yahoo.com/mrss/. Most bittorrent clients don't support XML namespaces in their generic form. Most clients that support the media:content tag assume that the namespace is called media in the feed, and will not recognize the tag otherwise.
For more information see the media RSS specification.
The media::content tag includes metadata as attributes. The ones relevant to bittorrent clients are url which is the torrent link, and filesize which is the size of the torrent's content (in bytes).
Example:
<media:content url="http://featuredcontent.utorrent.com/torrents/WillisEarlBeal-BitTorrent.torrent" fileSize="12216320"/>
media:hash
The media hash tag provides the info hash of the torrent hex encoded.
Example:
<media:hash algo="sha1"><8c056e06fbc16d2a2be79cefbf3e4ddc15396abe/media:hash>

[7] (2016-03-19 18:39:50 +09:00 版) <https://www.youtube.com/feeds/videos.xml?channel_id=UCpGY2vcoKXf7K6tFzsbSv7w>

<published>2016-03-17T07:00:42+00:00</published>
<updated>2016-03-19T08:12:25+00:00</updated>
<media:group>
<media:title>TVアニメ『無彩限のファントム・ワールド』第12話予告</media:title>
<media:content url="https://www.youtube.com/v/Qt6aRDta128?version=3" type="application/x-shockwave-flash" width="640" height="390"/>
<media:thumbnail url="https://i2.ytimg.com/vi/Qt6aRDta128/hqdefault.jpg" width="480" height="360"/>
<media:description>第12話「母は帰りぬ」

[8] (2016-03-19 18:40:08 +09:00 版) <https://www.youtube.com/feeds/videos.xml?channel_id=UCpGY2vcoKXf7K6tFzsbSv7w>

Ⓒ秦野宗一郎・京都アニメーション/無彩限の製作委員会</media:description>
<media:community>
<media:starRating count="213" average="4.98" min="1" max="5"/>
<media:statistics views="16650"/>
</media:community>
</media:group>
</entry>

[9] Media RSS Specification (2016-03-27 16:41:06 +09:00 版) <http://www.rssboard.org/media-rss>

The namespace for Media RSS is defined to be http://search.yahoo.com/mrss/

[10] Media RSS Namespace Extension (2012-12-30 00:58:23 +09:00 版) <http://www.feedforall.com/mediarss.htm>

Declaration: The name space for Media RSS is defined at http://search.yahoo.com/mrss
<rss version="2.0" xmlns:media="http://search.yahoo.com/mrss">

[11] (2016-03-26 11:20:03 +09:00 版) <http://www.tbsradio.jp/tsutaya/index.xml>

<rss xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:itunes="http://www.itunes.com/DTDs/Podcast-1.0.dtd" xmlns:media="http://search.yahoo.com/mrss" version="2.0">

[12] (2016-03-27 16:35:06 +09:00 版) <http://feeds.feedburner.com/hatena/b/hotentry>

xmlns:media="http://search.yahoo.com/mrss"

[13] XML::FeedPP - search.cpan.org (2016-03-27 16:45:27 +09:00 版) <http://search.cpan.org/~kawasaki/XML-FeedPP-0.43/lib/XML/FeedPP.pm>

$feed->xmlns( "xmlns:media" => "http://search.yahoo.com/mrss" );

[14] XML::FeedPP - search.cpan.org (2016-03-27 16:45:27 +09:00 版) <http://search.cpan.org/~kawasaki/XML-FeedPP-0.43/lib/XML/FeedPP.pm>

$feed->xmlns('xmlns:media' => 'http://search.yahoo.com/mrss/');

[15] Code Inside Blog | HowTo: Use PicLens and other MediaRSS Clients for your own Website (create MediaRSS with LINQ to XML) (Code Inside Team 著, 2016-03-24 17:29:10 +09:00 版) <http://blog.codeinside.eu/2008/07/01/howto-use-piclens-and-other-mediarss-clients-for-your-own-website-create-mediarss-with-linq-to-xml/>

XNamespace media = "http://search.yahoo.com/mrss";

[18] (2016-03-27 20:39:16 +09:00 版) <http://pronama-api.azurewebsites.net/feed/spaco?offset=0&count=0>

<media:content url="http://i1.wp.com/pronama.azurewebsites.net/wp-content/uploads/2016/02/160101.png"/>
<media:thumbnail url="http://pronama.azurewebsites.net/wp-content/uploads/2016/02/160101thumb.png"/>