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  <h1 class="title p-name" id="title" property="dcterms:title">MPEG Audio Byte Stream Format</h1>
  
  <h2 id="w3c-document-17-july-2014" property="dcterms:issued" content="2014-07-17T07:00:00.000Z" datatype="xsd:dateTime"><time class="dt-published" datetime="2014-07-17">17 July 2014</time></h2>
  <dl>
    
      <dt>This version:</dt>
      <dd><a href="http://www.w3.org/2013/12/byte-stream-format-registry/mpeg-audio-byte-stream-format.html">http://www.w3.org/2013/12/byte-stream-format-registry/mpeg-audio-byte-stream-format.html</a></dd>
      <dt>Latest editor's draft:</dt>
      <dd><a href="http://dvcs.w3.org/hg/html-media/raw-file/default/media-source/mpeg-audio-byte-stream-format.html">http://dvcs.w3.org/hg/html-media/raw-file/default/media-source/mpeg-audio-byte-stream-format.html</a></dd>
    
    
    <dt>Editors:</dt>
    <dd class="p-author h-card vcard" inlist="" rel="bibo:editor"><span typeof="foaf:Person"><span class="p-name fn" property="foaf:name">Aaron Colwell</span>, <a class="p-org org h-org h-card" href="http://www.google.com/" rel="foaf:workplaceHomepage">Google Inc.</a></span>
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<dd class="p-author h-card vcard" inlist="" rel="bibo:editor"><span typeof="foaf:Person"><span class="p-name fn" property="foaf:name">Dale Curtis</span>, <a class="p-org org h-org h-card" href="http://www.google.com/" rel="foaf:workplaceHomepage">Google Inc.</a></span>
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    <section class="introductory" id="abstract" typeof="bibo:Chapter" property="dcterms:abstract" datatype="" rel="bibo:Chapter" resource="#abstract"><h2 id="h2_abstract" role="heading" aria-level="1">Abstract</h2><p>
      This specification defines a <a href="http://www.w3.org/TR/media-source/">Media Source Extensions</a> byte stream format specification based on MPEG audio streams.
    </p></section><section class="introductory" id="sotd" typeof="bibo:Chapter" rel="bibo:Chapter" resource="#sotd"><h2 id="h2_sotd" role="heading" aria-level="1">Status of This Document</h2>
  
    
        <p>
          This document is merely a <abbr title="World Wide Web Consortium">W3C</abbr>-internal  document. It
          has no official standing of any kind and does not represent consensus of the <abbr title="World Wide Web Consortium">W3C</abbr>
          Membership.
        </p>
        
      
</section><section id="toc"><h2 class="introductory" id="h2_toc" role="heading" aria-level="1">Table of Contents</h2><ul class="toc" id="respecContents" role="directory"><li class="tocline"><a class="tocxref" href="#introduction"><span class="secno">1. </span>Introduction</a></li><li class="tocline"><a class="tocxref" href="#mime-types"><span class="secno">2. </span>MIME-types</a></li><li class="tocline"><a class="tocxref" href="#mpeg-audio-frames"><span class="secno">3. </span>MPEG Audio Frames</a></li><li class="tocline"><a class="tocxref" href="#mpeg-metadata"><span class="secno">4. </span>Metadata Frames</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#icecast"><span class="secno">4.1 </span>Icecast headers</a></li></ul></li><li class="tocline"><a class="tocxref" href="#mpeg-segments"><span class="secno">5. </span>Segment Definitions</a></li></ul></section>

    <section id="introduction" typeof="bibo:Chapter" rel="bibo:Chapter" resource="#introduction">
      <!--OddPage--><h2 id="h2_introduction" role="heading" aria-level="1"><span class="secno">1. </span>Introduction</h2>
      <p>This specification defines segment formats for implementations that choose to support MPEG audio streams specified in <a href="http://www.iso.org/iso/catalogue_detail.htm?csnumber=22412">ISO/IEC 11172-3:1993</a>, <a href="http://www.iso.org/iso/catalogue_detail.htm?csnumber=26797">ISO/IEC 13818-3:1998</a>, and <a href="http://www.iso.org/iso/catalogue_detail.htm?csnumber=53943">ISO/IEC 14496-3:2009</a>.</p>
      <p>It defines the <a href="#mime-types">MIME-types</a> used to signal codecs, and provides the necessary format specific definitions for <a href="http://www.w3.org/TR/media-source/#init-segment">initialization segments</a>, <a href="http://www.w3.org/TR/media-source/#media-segment">media segments</a>, and <a href="http://www.w3.org/TR/media-source/#random-access-point">random access points</a> required by the <a href="http://www.w3.org/TR/media-source/#byte-stream-formats">byte stream formats section</a> of the Media Source Extensions spec. It also defines extra behaviors and state that only apply to this byte stream format.</p>
    </section>

    <section id="mime-types" typeof="bibo:Chapter" rel="bibo:Chapter" resource="#mime-types">
      <!--OddPage--><h2 id="h2_mime-types" role="heading" aria-level="1"><span class="secno">2. </span>MIME-types</h2>
      <p>This section specifies the MIME-types that may be passed to <code><a href="http://www.w3.org/TR/media-source/#widl-MediaSource-isTypeSupported-boolean-DOMString-type">isTypeSupported()</a></code> or <code><a href="http://www.w3.org/TR/media-source/#widl-MediaSource-addSourceBuffer-SourceBuffer-DOMString-type">addSourceBuffer()</a></code> for byte streams that conform to this specification.</p>
      <ul>
        <li>"audio/aac" for sequences of ADTS frames, as specified in <a href="http://www.iso.org/iso/catalogue_detail.htm?csnumber=53943">ISO/IEC 14496-3:2009</a>.</li>
        <li>"audio/mpeg" for MPEG-1/2/2.5 Layer I/II/III streams, as specified in <a href="http://tools.ietf.org/html/rfc3003">RFC 3003</a>.</li>
      </ul>
      <p>The "codecs" MIME-type parameter must not be used with these MIME-types.</p>
    </section>

    <section id="mpeg-audio-frames" typeof="bibo:Chapter" rel="bibo:Chapter" resource="#mpeg-audio-frames">
      <!--OddPage--><h2 id="h2_mpeg-audio-frames" role="heading" aria-level="1"><span class="secno">3. </span>MPEG Audio Frames</h2>
      <p>The format of an <dfn id="mpeg-audio-frame">MPEG Audio Frame</dfn> depends on the <a href="#mime-types">MIME-type</a> used.</p>
      <ul>
        <li>If the "audio/aac" MIME-type is used, an MPEG Audio Frame is a sequence of bytes that conform to the adts_frame() syntax specified in Table 1.A.5 of <a href="http://www.iso.org/iso/catalogue_detail.htm?csnumber=53943">ISO/IEC 14496-3:2009</a>.</li>
        <li>If the "audio/mpeg" MIME-type is used, an MPEG Audio Frame is a sequence of bytes that conform to the frame() syntax element specified in Section 2.4.1.2 of <a href="http://www.iso.org/iso/catalogue_detail.htm?csnumber=22412">ISO/IEC 11172-3:1993</a> or the corresponding definition in <a href="http://www.iso.org/iso/catalogue_detail.htm?csnumber=26797">ISO/IEC 13818-3:1998</a>.</li>
      </ul>
    </section>

    <section id="mpeg-metadata" typeof="bibo:Chapter" rel="bibo:Chapter" resource="#mpeg-metadata">
      <!--OddPage--><h2 id="h2_mpeg-metadata" role="heading" aria-level="1"><span class="secno">4. </span>Metadata Frames</h2>
      <p>Since <a href="http://id3.org/ID3v1">ID3v1</a>, <a href="http://id3.org/id3v2.3.0">ID3v2</a> metadata frames, and <a href="#icecast-header">Icecast headers</a> are common in existing MPEG audio streams, implementations should gracefully handle such frames. Zero or more of these metadata frames are allowed to occur before, after, or between <a href="#mpeg-audio-frame">MPEG Audio Frames</a>. Minimal implementations must accept, consume, and ignore these frames. More advanced implementations may choose to expose the metadata information via an inband <code><a href="http://www.w3.org/TR/html5/embedded-content-0.html#texttrack">TextTrack</a></code> or some other mechanism.</p>

      <section id="icecast" typeof="bibo:Chapter" rel="bibo:Chapter" resource="#icecast">
        <h3 id="h3_icecast" role="heading" aria-level="2"><span class="secno">4.1 </span>Icecast headers</h3>
        <p>There is no normative spec for <a href="http://en.wikipedia.org/wiki/Icecast">Icecast</a>/<a href="http://en.wikipedia.org/wiki/SHOUTcast">SHOUTcast</a> headers, just <a href="http://forums.radiotoolbox.com/viewtopic.php?t=74">examples</a>. For the purpose of this specification, an <dfn id="icecast-header">Icecast header</dfn> is defined as beginning with the 4 character sequence "ICY&nbsp;"(U+0049 I, U+0043 C, U+0059 Y, U+0020 SPACE) and ending with a pair of carriage-return line-feed sequences (U+000D CARRIAGE RETURN, U+000A LINE FEED, U+000D CARRIAGE RETURN, U+000A LINE FEED).</p>
        <div class="note"><div class="note-title" id="h_note_1" role="heading" aria-level="3"><span>Note</span></div><p>Icecast headers are allowed in the byte streams because some Icecast and SHOUTcast
          servers return a status line that looks like "ICY OK 200" instead of a standard HTTP status line.
          User-agent network stacks typically interpret this as an HTTP 0.9 response and include the
          header in the response body. Allowing these headers to appear provides a simple way to
          interoperate with these servers.</p></div>
      </section>
    </section>

    <section id="mpeg-segments" typeof="bibo:Chapter" rel="bibo:Chapter" resource="#mpeg-segments">
      <!--OddPage--><h2 id="h2_mpeg-segments" role="heading" aria-level="1"><span class="secno">5. </span>Segment Definitions</h2>
      <p>The MPEG audio byte stream is a combination of one or more <a href="#mpeg-audio-frame">MPEG Audio Frames</a> and zero or more <a href="#mpeg-metadata">Metadata Frames</a>.</p>
      <ul>
        <li>Every <a href="#mpeg-audio-frame">MPEG Audio Frame</a> is a <a href="http://www.w3.org/TR/media-source/#random-access-point">random access point</a>.</li>
        <li>Every <a href="#mpeg-audio-frame">MPEG Audio Frame</a> header is an <a href="http://www.w3.org/TR/media-source/#init-segment">initialization segment</a>.</li>
        <li>The coded audio in each <a href="#mpeg-audio-frame">MPEG Audio Frame</a> is a <a href="http://www.w3.org/TR/media-source/#media-segment">media segment</a>.</li>
      </ul>
    </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> -->
  

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