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mp2t-byte-stream-format-respec.html
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mp2t-byte-stream-format-respec.html
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<!DOCTYPE html SYSTEM "about:legacy-compat">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>MPEG-2 TS Byte Stream Format</title>
<script src="https://www.w3.org/Tools/respec/respec-w3c-common" class="remove"></script>
<!--<script src="respec-w3c-common.js" class="remove"></script>-->
<script src="media-source.js" class="remove"></script>
<script class="remove">
(function() {
var mp2tContainerSpecDefinitions = {
'iso-13818-1': { fragment: 'http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=44169', link_text: 'ISO/IEC 13818-1', },
'mpeg2ts-timestampOffset': { helper_type: 'var', fragment: '#mpeg2ts-timestampOffset', link_text: 'MPEG2TS_timestampOffset', },
};
mediaSourceAddDefinitionInfo("mp2t-byte-stream-format", "", mp2tContainerSpecDefinitions);
})();
</script>
<script class="remove">
var respecConfig = {
// specification status (e.g. WD, LCWD, NOTE, etc.). If in doubt use ED.
specStatus: "ED",
// the specification's short name, as in http://www.w3.org/TR/short-name/
shortName: "mse-byte-stream-format-mp2t",
// if there a publicly available Editor's Draft, this is the link
edDraftURI: "https://w3c.github.io/media-source/mp2t-byte-stream-format.html",
// if this is a LCWD, uncomment and set the end of its review period
// lcEnd: "2009-08-05",
//publishDate: "2015-03-09",
prevVersion: "http://www.w3.org/2013/12/byte-stream-format-registry/mp2t-byte-stream-format.html",
// editors, add as many as you like
// only "name" is required
editors: [
{ name: "Matthew Wolenetz", url: "", company: "Google Inc.", companyURL: "http://www.google.com/" },
{ name: "Jerry Smith", url: "", company: "Microsoft Corporation", companyURL: "http://www.microsoft.com/" },
{ name: "Mark Watson", url: "", company: "Netflix Inc.", companyURL: "http://www.netflix.com/" },
{ name: "Aaron Colwell (until April 2015)", url: "", company: "Google Inc.", companyURL: "http://www.google.com/" },
{ name: "Adrian Bateman (until April 2015)", url: "", company: "Microsoft Corporation", companyURL: "http://www.microsoft.com/" },
],
mseDefGroupName: "mp2t-byte-stream-format",
mseUnusedGroupNameExcludeList: ["media-source"],
mseContributors: [
"Bob Lund",
"Alex Giladi",
"Duncan Rowden",
"Mark Vickers",
"Glenn Adams",
"Michael Thornburgh",
"David Singer",
],
// name of the WG
wg: "HTML Media Extensions Working Group",
// URI of the public WG page
wgURI: "https://www.w3.org/html/wg/",
// name (without the @w3c.org) of the public mailing to which comments are due
wgPublicList: "public-html-media",
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// Team Contact.
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noIDLIn: true,
scheme: "https",
otherLinks: [{
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data: [{
value: 'We are on GitHub',
href: 'https://github.com/w3c/media-source/'
}, {
value: 'File a bug',
href: 'https://github.com/w3c/media-source/issues'
}, {
value: 'Commit history',
href: 'https://github.com/w3c/media-source/commits/gh-pages/mp2t-byte-stream-format-respec.html'
}]
},{
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data: [{
value: 'public-html-media@w3.org',
href: 'https://lists.w3.org/Archives/Public/public-html-media/'
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}],
preProcess: [ mediaSourceAddMainSpecDefinitionInfos, mediaSourcePreProcessor ],
// Empty definitions for objects declared in the document are here to
// prevent error messages from being displayed for references to these objects.
definitionMap: {},
postProcess: [ mediaSourcePostProcessor ],
localBiblio: {
"INBANDTRACKS": {
title: "Sourcing In-band Media Resource Tracks from Media Containers into HTML",
href: "https://dev.w3.org/html5/html-sourcing-inband-tracks/",
authors: ["Bob Lund", "Silvia Pfeiffer"],
publisher: "W3C",
}
}
};
</script>
<!-- script to register bugs -->
<!-- Disabled unless/until it supports GitHub issues.
<script src="https://w3c.github.io/webcomponents/assets/scripts/bug-assist.js"></script>
<meta name="bug.short_desc" content="[MSE] ">
<meta name="bug.product" content="HTML WG">
<meta name="bug.component" content="Media Source Extensions">
-->
<link rel="stylesheet" href="mse.css">
</head>
<body>
<section id="abstract">
This specification defines a <a def-id="mse-spec"></a> [[!MEDIA-SOURCE]] byte stream format specification based on MPEG-2 Transport Streams.
</section>
<section id="sotd">
<p>The working group maintains <a href="https://github.com/w3c/media-source/issues">a list of all bug reports that the editors have not yet tried to address</a>; there may also be open bugs in the <a href="http://w3.org/brief/Mjcw">previous bug tracker</a>.</p>
<p>Implementors should be aware that this specification is not stable. <strong>Implementors who are not taking part in the discussions are likely to find the specification changing out from under them in incompatible ways.</strong> Vendors interested in implementing this specification before it eventually reaches the Candidate Recommendation stage should join the mailing list mentioned below and take part in the discussions.</p>
</section>
<section id="introduction">
<h2>Introduction</h2>
<p>This specification defines segment formats for implementations that choose to support MPEG-2 Transport Streams
[[!MPEG2TS]].</p> It defines the MIME-type parameters used to signal codecs, and provides
the necessary format specific definitions for <a def-id="init-segments"></a>, <a def-id="media-segments"></a>, and <a def-id="random-access-points"></a> required by
the <a def-id="byte-stream-formats-section"></a> of the Media Source Extensions spec. This document also defines extra behaviors and state that only apply to this
byte stream format.</p>
</section>
<section id="mime-parameters">
<h2>MIME-type info</h2>
<p>The MIME-type/subtype pair of "video/MP2T", as specified in [[!RFC3551]], MUST be used for byte streams that conform
to this specification.</p>
<p>This following parameters can be used in the MIME-type passed to <a def-id="isTypeSupported"></a> or <a def-id="addSourceBuffer"></a>.</p>
<dl>
<dt>codecs</dt>
<dd>
A comma separated list of codec IDs used to specify what codecs will be used in the byte stream. Implementations SHOULD accept IDs in the form specified by [[!RFC6381]].
<div class="note">Implementations MAY only implement a subset of the codecs and profiles mentioned in the RFC.</div>
</dd>
</dl>
</section>
<section id="mpeg2ts-general">
<h4>General Transport Stream Requirements</h4>
<p>MPEG-2 TS media and initialization segments MUST conform to the MPEG-2 TS Adaptive Profile (ISO/IEC 13818-1:2012 Amd. 2).</p>
<p>The user agent MUST run the <a def-id="append-decode-error-algorithm"></a> if any of the following conditions are met:</p>
<ol>
<li>Segments do not contain complete MPEG-2 TS packets.</li>
<li>Segments do not contain complete PES packets and sections.</li>
<li>Segments contain more than one program.</li>
<li>At least one MPEG-2 TS packet has a non-zero transport_error_indicator.</li>
</ol>
</section>
<section id="mpeg2ts-init-segments">
<h4>Initialization Segments</h4>
<p>An MPEG-2 TS initialization segment consists of a single PAT and a single PMT.</p>
<p>The user agent MUST run the <a def-id="append-decode-error-algorithm"></a> if any of the following conditions are met:</p>
<ol>
<li>A PAT is not present in the <a def-id="init-segment"></a></li>
<li>A PMT is not present in the <a def-id="init-segment"></a></li>
</ol>
<p>The user agent MUST accept and ignore other SI, such as CAT, that are invariant for all subsequent media segments.</p>
<p>The user agent MUST source attribute values for id, kind, label and language for <a def-id="audio-track"></a>, <a def-id="video-track"></a> and
<a def-id="text-track"></a> objects as described for MPEG-2 Transport Streams in the in-band tracks spec [[INBANDTRACKS]].</p>
</section>
<section id="mpeg2ts-media-segments">
<h4>Media Segments</h4>
<p>The user agent MUST run the <a def-id="append-decode-error-algorithm"></a> if any of the following conditions are met:</p>
<ol>
<li>A media segment relies on initialization information in another media segment.</li>
<li>At least one PES packet does not have a PTS timestamp.</li>
<li>PCR is not present in the Segment prior to the first byte of a TS packet payload containing media data.</li>
</ol>
The user agent will accept and ignore PSI that is identical to the information in the last initialization segment which may appear repeatedly throughout the segment.
</section>
<section id="mpeg2ts-random-access-points">
<h4>Random Access Points</h4>
<p>A random access point as defined in this specification corresponds to Elementary Stream Random Access Point as defined in
[[!MPEG2TS]].</p>
</section>
<section id="mpeg2ts-discontinuities">
<h4>Timestamp Rollover & Discontinuities</h4>
<p>Timestamp rollovers and discontinuities MUST be handled by the UA. The UA's MPEG-2 TS implementation MUST maintain an internal offset
variable, <dfn id="mpeg2ts-timestampOffset">MPEG2TS_timestampOffset</dfn>, to keep track of the offset that needs to be applied to timestamps
that have rolled over or are part of a discontinuity. <var>MPEG2TS_timestampOffset</var> is initially set to 0 when the <a class="externalDFN">SourceBuffer</a> is
created. This offset MUST be applied to the timestamps as part of the conversion process from MPEG-2 TS packets
into <a def-id="coded-frames"></a> for the <a def-id="coded-frame-processing-algorithm"></a>. This results in the coded frame timestamps
for a packet being computed by the following equations:</p>
<pre>
Coded Frame Presentation Timestamp = (MPEG-2 TS presentation timestamp) + <var>MPEG2TS_timestampOffset</var>
Coded Frame Decode Timestamp = (MPEG-2 TS decode timestamp) + <var>MPEG2TS_timestampOffset</var></pre>
<p><a def-id="mpeg2ts-timestampOffset"></a> is updated in the following ways:</p>
<ul>
<li>Each time a timestamp rollover is detected, 2^33 MUST be added to <a def-id="mpeg2ts-timestampOffset"></a>.</li>
<li>When a discontinuity is detected, <a def-id="mpeg2ts-timestampOffset"></a> MUST be adjusted to make the timestamps after the discontinuity appear
to come immediately after the timestamps before the discontinuity.</li>
<li>When <a def-id="abort"></a> is called, <a def-id="mpeg2ts-timestampOffset"></a> MUST be set to 0.</li>
<li>When <a def-id="timestampOffset"></a> is successfully set, <a def-id="mpeg2ts-timestampOffset"></a> MUST be set to 0.</li>
</ul>
</section>
<section id="conformance"></section>
<section id="acknowledgements">
<h2>Acknowledgments</h2>
The editors would like to thank <a def-id="contributors"></a> for their contributions to this specification.
</section>
</body>
</html>