One document matched: draft-cbran-rtcweb-codec-00.xml

<?xml version="1.0" encoding="US-ASCII"?>
<!DOCTYPE rfc SYSTEM "rfc2629.dtd">
<?rfc toc="yes"?>
<?rfc tocompact="yes"?>
<?rfc tocdepth="3"?>
<?rfc tocindent="yes"?>
<?rfc symrefs="yes"?>
<?rfc sortrefs="yes"?>
<?rfc comments="yes"?>
<?rfc inline="yes"?>
<?rfc compact="yes"?>
<?rfc subcompact="no"?>
<rfc category="std" docName="draft-cbran-rtcweb-codec-00"
     ipr="noDerivativesTrust200902">
  <front>
    <title abbrev="Abbreviated-Title">RTC-Web Codec and Media Processing
    Requirements</title>

    <author fullname="Cary Bran" initials="C." surname="Bran">
      <organization>Cisco</organization>

      <address>
        <postal>
          <street>170 West Tasman Drive</street>

          <city>San Jose</city>

          <region>CA</region>

          <code>95134</code>

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

        <phone>+1 206 256-3502</phone>

        <email>cbran@cisco.com</email>
      </address>
    </author>

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

      <address>
        <postal>
          <street>170 West Tasman Drive</street>

          <city>San Jose</city>

          <region>CA</region>

          <code>95134</code>

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

        <phone>+1 408 421-9990</phone>

        <email>fluffy@cisco.com</email>
      </address>
    </author>

    <date day="28" month="June" year="2011" />

    <abstract>
      <t>This document outlines the codec and media processing requirements
      for RTC-Web client application and endpoint devices. </t>
    </abstract>
  </front>

  <middle>
    <section title="Introduction">
      <t>An integral part of the success and adoption of the Real-Time
      Communications Web (RTC-WEB) will be the interoperability between
      RTC-Web applications. This specification will focus on the media
      processing and codec requirements for RTC-Web client applications.</t>

      <t>Media processing and codec requirements fit into a series of
      specifications have been created to address RTC-Web communications
      protocols, security requirements, data transmission and use cases. More
      information on the RTC-Web can be found here:</t>

      <t>[TODO put links to supporting drafts here]</t>
    </section>

    <section title="Terminology">
      <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 title="Codec Requirements">
      <t>This section covers the audio and video codec requirements for
      RTC-WEB client applications. To ensure a baseline level of
      interoperability between RTC-Web applications, a minimum set of required
      codes is specified below. While this section specifies the codecs that
      will be supported by all RTC-Web application implementations, it leaves
      the question of supporting additional codecs to the will of the
      implementer.</t>

      <section title="Audio Codec Requirements">
        <t>RTC-WEB applications are REQUIRED to implement the following audio
        codecs.</t>

        <t><list style="symbols">
            <t>PCMA/PCMU - see section 4.5.14 of <xref
            target="RFC3551"></xref></t>

            <t>Telephone-event - <xref target="RFC4734"></xref></t>

            <t>Opus [draft-ietf-codec-opus]</t>
          </list></t>

        <t>Implementations of the PCMU and PMCA codecs are REQUIRED to support
        1 channel with a rate of 8000 and a ptime of 20.</t>

        <t>The following codecs are OPTIONAL for RTC-WEB application
        implementations.</t>

        <t><list style="symbols">
            <t>G729</t>

            <t>G722</t>

            <t>G722.1</t>

            <t>G723</t>

            <t>AMR</t>

            <t>AMR-WB</t>

            <t>iLBC</t>

            <t>L16</t>
          </list> [Open Issue: minimum profile and identifying any additional
        mandatory to implement audio codecs.]</t>
      </section>

      <section title="Video Codec Requirements">
        <t>RTC-WEB applications are REQUIRED to implement the following video
        codecs.</t>

        <t><list style="symbols">
            <t>VP8 <xref target="I-D.webm"></xref></t>
          </list></t>

        <t>The following feature list applies to all required video
        codecs.</t>

        <t>Required video codecs:</t>

        <t><list style="symbols">
            <t>MUST support at least 10 frames per second (fps) and SHOULD
            support 30 fps</t>

            <t>MUST support a the bilinear and none reconstruction filters</t>

            <t>OPTIONALLY offer support for additional color spaces</t>

            <t>MUST support a minimum resolution of 320X240</t>

            <t>SHOULD support resolutions of 1280x720, 720x480, 1024x768,
            800x600, 640x480, 640 x 360 , 320x240</t>
          </list></t>

        <t>The following video codecs are OPTIONAL for RTC-WEB application
        implementations.</t>

        <t><list style="symbols">
            <t>H.263</t>

            <t>H.264-AVC</t>

            <t>H.264-SVC</t>
          </list></t>
      </section>
    </section>

    <section title="RTC-Web Endpoint Device Requirements">
      <t>It is plausible that the dominant near-to-mid term RTC-Web usage
      model will be people using the RTC-Web functionality to communicate with
      each other via web browsers typically running within a notebook computer
      that has built-in microphone and speakers. The
      notebook-as-communication-device paradigm presents challenging echo
      cancellation and audio gain problems, the specific remedy of which will
      not be mandated here. However, while no specific algorithm or standard
      will be required by RTC-Web compatible endpoints, it has been found that
      functionality such as automatic gain control, echo cancellation, and
      headset detection will improve the user experience and should be
      implemented by the endpoint device.</t>

      <t>To address the problems outlined above, suitable implementations of
      the functionality listed below SHOULD be available within an RTC-Web
      endpoint device. </t>

      <t><list style="symbols">
          <t>Automatic gain control</t>

          <t>Echo cancellation, including acoustic echo cancelation</t>

          <t>Headset detection</t>

          <t>Auto-adjustments to gain control and echo cancelation algorithms
          based on if headset or internal speakers/microphone is being used
          </t>
        </list></t>
    </section>

    <section title="Legacy VoIP Interoperability">
      <t>The codec requirements above will ensure, at a minimum, voice
      interoperability capabilities between RTC-Web client applications and
      legacy phone systems.</t>

      <t>Video interoperability will be dependent upon the support, natively
      or through transcoding, of VP8 by the phone system vendors or the
      availability of an interoperable codec, such as H.264-AVC, from within
      the RTC-Web client application implementation.</t>
    </section>

    <section anchor="IANA" title="IANA Considerations">
      <t>This document makes no request of IANA.</t>

      <t>Note to RFC Editor: this section may be removed on publication as an
      RFC.</t>
    </section>

    <section anchor="Security" title="Security Considerations">
      <t>The codec requirements have no additional security considerations
      other than those captured in <xref
      target="I-D.ekr-security-considerations-for-rtc-web"></xref>.</t>
    </section>

    <section anchor="Acknowledgements" title="Acknowledgements">
      <t>This draft incorporates ideas and text from various other drafts. In
      particularly we would like to acknowledge, and say thanks for, work we
      incorporated from Harald Alvestrand.</t>
    </section>
  </middle>

  <back>
    <references title="Normative References">
      <?rfc include="http://xml.resource.org/public/rfc/bibxml/reference.RFC.2119.xml"?>

      <?rfc include='http://xml.resource.org/public/rfc/bibxml/reference.RFC.3551.xml'?>

      <?rfc include='http://xml.resource.org/public/rfc/bibxml/reference.RFC.4734.xml'?>

      <reference anchor="I-D.ekr-security-considerations-for-rtc-web">
        <front>
          <title abbrev="RTC-Web Security">Security Considerations for
          RTC-Web</title>

          <author fullname="Eric Rescorla" initials="E.K." surname="Rescorla">
            <organization>RTFM, Inc.</organization>

            <address>
              <postal>
                <street>2064 Edgewood Drive</street>

                <city>Palo Alto</city>

                <region>CA</region>

                <code>94303</code>

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

              <phone>+1 650 678 2350</phone>

              <email>ekr@rtfm.com</email>
            </address>
          </author>

          <date day="30" month="May" year="2011" />

          <area>RAI</area>

          <workgroup>RTC-Web</workgroup>

          <abstract>
            <t>The Real-Time Communications on the Web (RTC-Web) working group
            is tasked with standardizing protocols for real-time
            communications between Web browsers. The two major use cases for
            RTC-Web technology are real-time audio and/or video calls and
            direct data transfer. Unlike most conventional real-time systems
            (e.g., SIP-based soft phones) RTC-Web communications are directly
            controlled by some Web server, which poses new security
            challenges. For instance, a Web browser might expose a JavaScript
            API which allows a server to place a video call. Unrestricted
            access to such an API would allow any site which a user visited to
            "bug" a user's computer, capturing any activity which passed in
            front of their camera. This document defines the RTC-Web threat
            model and defines an architecture which provides security within
            that threat model.</t>
          </abstract>

          <note title="Legal">
            <t>THIS DOCUMENT AND THE INFORMATION CONTAINED THEREIN ARE
            PROVIDED ON AN “AS IS” BASIS AND THE CONTRIBUTOR, THE
            ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE
            INTERNET SOCIETY, THE IETF TRUST, AND THE INTERNET ENGINEERING
            TASK FORCE, DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
            BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
            THEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
            MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.</t>
          </note>
        </front>
      </reference>

      <reference anchor="I-D.webm">
        <front>
          <title>VP8 Data Format and Decoding Guide</title>

          <author fullname="Google, Inc." surname="Google, Inc.">
            <organization></organization>
          </author>

          <date month="July" year="2010" />

          <note title="Link to WebM Project">
            <t>http://www.webmproject.org</t>
          </note>
        </front>
      </reference>
    </references>
  </back>
</rfc>