[33] [DFN[Media Source Extensions]] ([DFN[MSE]]) は、
[[動画]]や[[音声]]のデータを [[JavaScript]] で用意し、
[[媒体要素]]に供給するための [[API]] です。

* 仕様書

[REFS[
- [29] [CITE@en[Media Source Extensions™]] ([TIME[2016-11-17 04:05:37 +09:00]]) <https://w3c.github.io/media-source/>
]REFS]

* API

[31] 
[FIG(short list)[
- [CODE(DOMi)@en[MediaSource]]
- [CODE(DOMi)@en[SourceBuffer]]
- [CODE(DOMi)@en[SourceBufferList]]
- [CODE(DOMm)@en[createObjectURL]]
- [CODE(DOMm)@en[sourceBuffer]]
]FIG]

* 問題

[30] [CITE[File API]] や [CITE[HTML Standard]] に[[猿パッチ]]を当てる形で変更を加えています。
そのため現代的な[[仕様書]]レベルの品質の規定になっていません。

[32] [CSECTION@en[Introduction]] の図には「Video Tag Display Region」
が描かれていて、どうやら[[動画]]の描画域を表していそうです。
21世紀になって十年以上が過ぎて、未だに[[タグ]]と[[要素]]の[[ボックス]]の区別もつかないような人が[[仕様書]]の編集に携わっているということで、
不安になります。

* 歴史

[5] [CITE@en[Media Source Extensions Byte Stream Format Registry]]
( ([TIME[2014-08-26 06:16:54 +09:00]] 版))
<https://dvcs.w3.org/hg/html-media/raw-file/tip/media-source/byte-stream-format-registry.html>

[6] [CITE@en[Netflix, MSE, and EME]]
( ([[Anne van Kesteren]] 著, [TIME[2014-11-15 07:49:27 +09:00]] 版))
<http://lists.w3.org/Archives/Public/public-webappsec/2014Nov/0257.html>

[7] [CITE@en[Adaptive Streaming - WHATWG Wiki]]
( ([TIME[2014-10-11 12:16:49 +09:00]] 版))
<https://wiki.whatwg.org/wiki/Adaptive_Streaming>

[8] [CITE@en[Media Source Extensions]]
([TIME[2015-01-10 04:24:16 +09:00]] 版)
<https://w3c.github.io/media-source/>

[9] [CITE@en[Fetch, MSE, and MIX]]
([[Ryan Sleevi]] 著, [TIME[2015-02-20 14:06:17 +09:00]] 版)
<https://lists.w3.org/Archives/Public/public-webappsec/2015Feb/0371.html>

[1] [CITE@en[Media Source Extensions]]
( ([TIME[2015-03-31 04:07:29 +09:00]] 版))
<http://www.w3.org/TR/2015/CR-media-source-20150331/>

[2] [CITE@en[Media Source Extensions]]
([TIME[2015-07-15 03:03:48 +09:00]] 版)
<https://w3c.github.io/media-source/>

[3] [CITE@en[778617 – (MSE) Tracking bug for Media Source Extensions API implementation]]
([TIME[2015-11-05 17:05:20 +09:00]] 版)
<https://bugzilla.mozilla.org/show_bug.cgi?id=778617>

[FIG(quote)[
[FIGCAPTION[
[4] [CITE@ja[Media Source Extensions (MSE) (Windows)]]
([TIME[2015-11-05 17:05:37 +09:00]] 版)
<https://msdn.microsoft.com/library/dn594470(v=vs.85).aspx>
]FIGCAPTION]

> Internet Explorer 11 では、HTML5 の Media Source Extensions (MSE) を使った MPEG-DASH メディア ストリーミングのサポートが導入されています。

]FIG]


[10] [CITE@en[Media Source Extensions]]
( ([TIME[2015-11-11 06:03:34 +09:00]] 版))
<http://www.w3.org/TR/2015/CR-media-source-20151112/>

[11] [CITE@en[RE: MSE progress]]
([[Paul Cotton]] 著, [TIME[2016-02-03 09:00:00 +09:00]] 版)
<https://lists.w3.org/Archives/Public/www-archive/2016Feb/0006.html>

[12] [CITE@en[Integrate with MSE's "Detaching from a media element" · whatwg/html@cf9e802]]
([TIME[2016-03-16 14:17:24 +09:00]] 版)
<https://github.com/whatwg/html/commit/cf9e80296bb5911c85653e36254a270e0e1701a1>

[13] [CITE@en[Media Source Extensions]]
( ([TIME[2016-05-03 21:15:57 +09:00]]))
<https://www.w3.org/TR/2016/CR-media-source-20160503/>

[FIG(quote)[
[FIGCAPTION[
[14] [CITE@en[W3C HTML Media Extensions Working Group]]
( ([TIME[2015-12-03 00:44:06 +09:00]]))
<https://www.w3.org/html/wg/>
]FIGCAPTION]

> Note: As of December 2, 2015, only the HTML Media Extensions remain to be accomplished within the scope of the charter and the Group was renamed accordingly. Future work on HTML is now happening in the Web Platform Working Group.

]FIG]


[15] [CITE@en[Media Source Extensions]]
([TIME[2016-07-05 19:25:38 +09:00]])
<https://www.w3.org/TR/2016/CR-media-source-20160705/>

[16] [CITE@en[w3c/HTMLSourcingInbandTracks: Specification for sourcing inband tracks into HTML]]
([TIME[2016-09-02 11:26:58 +09:00]])
<https://github.com/w3c/HTMLSourcingInbandTracks>

[17] [CITE@en[Media Source Extensions™]]
([TIME[2016-10-04 15:27:22 +09:00]])
<https://www.w3.org/TR/2016/PR-media-source-20161004/>

[18] [[W3C]] の謎 [[[SUP[TM]]]] は [[XHTML]] 以来?

[19] [CITE@en[Media Source Extensions]]
([TIME[2016-10-04 05:41:58 +09:00]])
<https://w3c.github.io/media-source/>

[20] なぜか [[ED]] にはない [[[SUP[TM]]]]。

[21] [CITE@en[w3c/media-source: Media Source Extensions]]
([TIME[2016-10-05 09:18:55 +09:00]])
<https://github.com/w3c/media-source>

[FIG(quote)[
[FIGCAPTION[
[22] [CITE@en[Fixed a lot of invalid markup. one https. some dates.]]
([[plehegar]]著, [TIME[2016-10-04 05:41:30 +09:00]])
<https://github.com/w3c/media-source/commit/94904b87bdeb28f73690d864d3290b97fc981d25>
]FIGCAPTION]

> 
>  -    <title>Media Source Extensions</title>
>  +    <title>Media Source Extensions™</title>

]FIG]


[23] [CITE@en[Media Source Extensions Byte Stream Format Registry]]
([TIME[2016-10-04 08:17:32 +09:00]])
<https://www.w3.org/TR/2016/NOTE-mse-byte-stream-format-registry-20161004/>

[24] [CITE@en[MPEG-2 TS Byte Stream Format]]
([TIME[2016-10-04 10:24:02 +09:00]])
<https://www.w3.org/TR/2016/NOTE-mse-byte-stream-format-mp2t-20161004/>

[25] [CITE@en[MPEG Audio Byte Stream Format]]
([TIME[2016-10-04 10:20:27 +09:00]])
<https://www.w3.org/TR/2016/NOTE-mse-byte-stream-format-mpeg-audio-20161004/>

[26] [CITE@en[ISO BMFF Byte Stream Format]]
([TIME[2016-10-04 10:24:53 +09:00]])
<https://www.w3.org/TR/2016/NOTE-mse-byte-stream-format-isobmff-20161004/>

[27] [CITE@en[WebM Byte Stream Format]]
([TIME[2016-10-04 10:23:12 +09:00]])
<https://www.w3.org/TR/2016/NOTE-mse-byte-stream-format-webm-20161004/>

[28] [CITE@en[Media Source Extensions™]]
([TIME[2016-11-17 04:09:02 +09:00]])
<https://www.w3.org/TR/2016/REC-media-source-20161117/>

[34] [CITE@en[We'll Cross the (Media) Streams, Ray  |  Web  |  Google Developers]]
( ([TIME[2017-03-21 22:29:23 +09:00]]))
<https://developers.google.com/web/updates/2017/03/mixing-streams>

[35] [CITE@en[Media Updates in Chrome 61  |  Web  |  Google Developers]]
([TIME[2017-08-28 23:10:08 +09:00]])
<https://developers.google.com/web/updates/2017/07/chrome-61-media-updates>

[36] [CITE@en[Audio/Video Updates in Chrome 69  |  Web  |  Google Developers]]
([TIME[2018-08-09 06:28:56 +09:00]])
<https://developers.google.com/web/updates/2018/08/chrome-69-media-updates>