One document matched: draft-burnett-rtcweb-constraints-registry-00.xml

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<rfc category="std" docName="draft-burnett-rtcweb-constraints-registry-00" ipr="trust200902">
  <front>
    <title abbrev="constraints-registry">IANA Registry for RTCWeb Media Constraints</title>

    <author fullname="Daniel C. Burnett" initials="D." surname="Burnett">
      <organization>Voxeo</organization>

      <address>
        <postal>
          <street>189 South Orange Avenue #1000</street>

          <city>Orlando</city>

          <region>FL</region>

          <code>32801</code>

          <country>USA</country>
        </postal>

        <email>dburnett@voxeo.com</email>
      </address>
    </author>

    <date day="2" month="March" year="2012" />

    <area>Real-time Applications and Infrastructure</area>

    <workgroup>RTCWEB</workgroup>

    <abstract>
      <t>Specifications in W3C's Media Capture Task Force and WebRTC Working
      Group have need of a registry in which to maintain a list of HTML Media
      constraints. This document defines this registry.</t>
    </abstract>
  </front>

  <middle>
    <section anchor="sec.introduction" title="Introduction">
      <t>There are two W3C specifications that have need of a registry in
      which to represent constraints: <xref
      target="W3C.WD-getusermedia-2012xxxx">getusermedia: Getting access to
      local devices that can generate multimedia streams</xref> and <xref
      target="W3C.WD-webrtc-20120209">WebRTC 1.0: Real-time Communication
      Between Browsers</xref>. In the former, the getUserMedia() method on the
      NavigatorUserMedia interface takes an "options" argument (which may be
      renamed "constraints"). In the latter, the addMedia() method on the
      PeerConnection interface takes a "hints" parameter (soon to be renamed
      "constraints"). Both of these parameters make use of a data structure
      representing a list of constraints on the HTML media or media connection
      to be established. Additionally, both specifications also (will soon)
      define getCapabilities() methods that are used to query the web browser
      about its capabilities. The returned data structure specifies the
      browser's capabilities in terms of constraints that it can satisfy. The
      data structures and their use are defined in the aforementioned
      specifications. This document specifies the registry used to define
      individual constraint names, their allowed values, and their
      meanings.</t>
    </section>

    <section title="Requirements Language">
      <t>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
      "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
      document are to be interpreted as described in <xref target="RFC2119">
      RFC 2119</xref>.</t>
    </section>

    <section anchor="sec.iana" title="IANA Considerations">
      <t>This document defines a registry "RTCWeb Media Constraints" for use
      by W3C specifications needing to indicate constraints on HTML Media,
      both as used by web application authors to indicate preferences and as
      used by web browsers to indicate constraints they can satisfy.</t>

      <section anchor="sec.registry.mediacon" title="RTCWeb Media Constraints">
        <t>IANA SHALL create a new name space of "RTCWeb Media Constraints".
        All maintenance within and additions to the contents of this name
        space MUST be according to the "Specification Required with Expert
        Review" registration policy as defined in <xref
        target="RFC5226">RFC5226</xref>. The registry is initially empty. The
        registry is defined in the remainder of this section.</t>

        <t>Each registry entry consists of a Name and a Reference (or list of
        references).</t>

        <t>An RTCWeb Media Constraint Name MUST satisfy the following <xref
        target="RFC5234">ABNF</xref> specification:</t>

        <figure>
          <artwork><![CDATA[
rtcweb-media-constraint = media-type "-" constraint-type "-" constraint
media-type              = "audio" / "video"
constraint-type         = "min" / "max" / "enum"
constraint              = ALPHA 0*constraint-char
constraint-char         = ALPHA / DIGIT / "-"

]]></artwork>
        </figure>

        <t>Constraint names are case-sensitive.</t>

        <t>A registration request MUST include the following information:</t>

        <t><list style="symbols">
            <t>The constraint name to be registered</t>

            <t>Name and Email address of a contact person for the
            registration</t>

            <t>Organization or individuals having the change control</t>

            <t>Reference(s) to the specification(s) defining the
            constraint</t>
          </list></t>

        <section title="Designated Expert Instructions">
          <t>Constraint names are of unlimited length according to the syntax.
          However, it is RECOMMENDED that they be no longer than 80 characters
          in total. This is to keep them reasonable for humans to read and
          use.</t>

          <t>A constraint name with media-type of "audio" MUST be relevant to
          audio media streams and connections. A constraint of media-type
          "video" MUST be relevant to video media streams and connections.</t>

          <t>A constraint MUST satisfy the following criteria based upon its
          constraint-type:</t>

          <t><list hangIndent="6" style="hanging">
              <t hangText="min"><vspace blankLines="0" />When used by a web
              application author, the constraint MUST represent the minimum
              value the author is willing to accept. When returned by a web
              browser as a capability, the constraint MUST represent the
              minimum value that the web browser could satisfy if requested to
              by the web application author. The constraint specification MUST
              clearly define the units associated with the value if the value
              itself does not specify them.</t>

              <t hangText="max"><vspace blankLines="0" />When used by a web
              application author, the constraint MUST represent the maximum
              value the author is willing to accept. When returned by a web
              browser as a capability, the constraint MUST represent the
              maximum value that the web browser could satisfy if requested to
              by the web application author. The constraint specification MUST
              clearly define the units associated with the value if the value
              itself does not specify them.</t>

              <t hangText="enum"><vspace blankLines="0" />The constraint
              specification MUST enumerate all allowed values.</t>
            </list></t>

          <t></t>

          <t>The constraint MUST be well enough defined in the specification
          that it is understandable by implementors and application developers
          that will use the constraint. The constraint SHOULD NOT duplicate a
          condition that can be achieved using constraints already defined in
          the registry. The constraint name SHOULD be appropriate and specific
          enough for the constraint.</t>
        </section>
      </section>
    </section>

    <section anchor="sec.securityConsiderations"
             title="Security Considerations">
      <t>Since the constraints envisioned for this registry are fairly generic
      in nature, it is not expected that the mere existence of this registry
      will introduce any particular security issues. Any specification
      defining one or more new constraints SHOULD address any specific
      security issues that might be introduced by the constraint(s).</t>
    </section>
  </middle>

  <back>
    <references title="Normative References">
      <!--Key words for use in RFCs to Indicate Requirement Levels-->

      &rfc2119;

      <!--ABNF-->

      &rfc5234;

      <!--Guidelines for Writing an IANA Considerations Section in RFCs-->

      &rfc5226;
    </references>

    <references title="Informative References">
      <!-- WebRTC -->

      <reference anchor="W3C.WD-webrtc-20120209"
                 target="http://www.w3.org/TR/2012/WD-webrtc-20120209">
        <front>
          <title>WebRTC 1.0: Real-Time Communication Between Browsers</title>

          <author fullname="Adam Bergkvist" initials="A." surname="Bergkvist">
            <organization>Ericsson</organization>
          </author>

          <author fullname="Daniel C. Burnett" initials="D." surname="Burnett">
            <organization>Voxeo</organization>
          </author>

          <author fullname="Cullen Jennings" initials="C." surname="Jennings">
            <organization>Cisco</organization>
          </author>

          <author fullname="Anant Narayanan" initials="A." surname="Narayanan">
            <organization>Mozilla</organization>
          </author>

          <date day="9" month="February" year="2012" />
        </front>

        <seriesInfo name="World Wide Web Consortium WD"
                    value="WD-webrtc-20120209" />

        <format target="http://www.w3.org/TR/2012/WD-webrtc-20120209"
                type="HTML" />
      </reference>

      <!-- getusermedia -->

      <reference anchor="W3C.WD-getusermedia-2012xxxx"
                 target="http://www.w3.org/TR/2012/WD-getusermedia-2012xxxx">
        <front>
          <title>getusermedia: Getting access to local devices that can
          generate multimedia streams</title>

          <author fullname="Daniel C. Burnett" initials="D." surname="Burnett">
            <organization>Voxeo</organization>
          </author>

          <author fullname="Anant Narayanan" initials="A." surname="Narayanan">
            <organization>Mozilla</organization>
          </author>

          <date day="X" month="XXX" year="2012" />
        </front>

        <seriesInfo name="World Wide Web Consortium WD"
                    value="WD-getusermedia-2012xxxx" />

        <format target="http://www.w3.org/TR/2012/WD-getusermedia-2012xxxx"
                type="HTML" />
      </reference>
    </references>

    <section title="Acknowledgements">
      <t>The authors would like to thank the members of the W3C Media Capture
      Task Force and WebRTC Working Group, the members of the IETF RTCWEB
      Working Group, and the people who gave specific early review and
      feedback: Cullen Jennings and Travis Leithead.</t>

      <t></t>
    </section>
  </back>
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