Network Working Group C. Bran Internet-Draft C. Jennings Intended status: Standards Track Cisco Expires: December 30, 2011 June 28, 2011 RTC-Web Codec and Media Processing Requirements draft-cbran-rtcweb-codec-00 Abstract This document outlines the codec and media processing requirements for RTC-Web client application and endpoint devices. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. This document may not be modified, and derivative works of it may not be created, and it may not be published except as an Internet-Draft. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on December 30, 2011. Copyright Notice Copyright (c) 2011 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Bran & Jennings Expires December 30, 2011 [Page 1] Internet-Draft Abbreviated-Title June 2011 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Codec Requirements . . . . . . . . . . . . . . . . . . . . . . 3 3.1. Audio Codec Requirements . . . . . . . . . . . . . . . . . 3 3.2. Video Codec Requirements . . . . . . . . . . . . . . . . . 4 4. RTC-Web Endpoint Device Requirements . . . . . . . . . . . . . 5 5. Legacy VoIP Interoperability . . . . . . . . . . . . . . . . . 5 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 7. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6 9. Normative References . . . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6 Bran & Jennings Expires December 30, 2011 [Page 2] Internet-Draft Abbreviated-Title June 2011 1. Introduction 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. 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: [TODO put links to supporting drafts here] 2. Terminology 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 RFC 2119 [RFC2119]. 3. Codec Requirements 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. 3.1. Audio Codec Requirements RTC-WEB applications are REQUIRED to implement the following audio codecs. o PCMA/PCMU - see section 4.5.14 of [RFC3551] o Telephone-event - [RFC4734] o Opus [draft-ietf-codec-opus] Implementations of the PCMU and PMCA codecs are REQUIRED to support 1 channel with a rate of 8000 and a ptime of 20. The following codecs are OPTIONAL for RTC-WEB application implementations. Bran & Jennings Expires December 30, 2011 [Page 3] Internet-Draft Abbreviated-Title June 2011 o G729 o G722 o G722.1 o G723 o AMR o AMR-WB o iLBC o L16 [Open Issue: minimum profile and identifying any additional mandatory to implement audio codecs.] 3.2. Video Codec Requirements RTC-WEB applications are REQUIRED to implement the following video codecs. o VP8 [I-D.webm] The following feature list applies to all required video codecs. Required video codecs: o MUST support at least 10 frames per second (fps) and SHOULD support 30 fps o MUST support a the bilinear and none reconstruction filters o OPTIONALLY offer support for additional color spaces o MUST support a minimum resolution of 320X240 o SHOULD support resolutions of 1280x720, 720x480, 1024x768, 800x600, 640x480, 640 x 360 , 320x240 The following video codecs are OPTIONAL for RTC-WEB application implementations. o H.263 Bran & Jennings Expires December 30, 2011 [Page 4] Internet-Draft Abbreviated-Title June 2011 o H.264-AVC o H.264-SVC 4. RTC-Web Endpoint Device Requirements 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. To address the problems outlined above, suitable implementations of the functionality listed below SHOULD be available within an RTC-Web endpoint device. o Automatic gain control o Echo cancellation, including acoustic echo cancelation o Headset detection o Auto-adjustments to gain control and echo cancelation algorithms based on if headset or internal speakers/microphone is being used 5. Legacy VoIP Interoperability The codec requirements above will ensure, at a minimum, voice interoperability capabilities between RTC-Web client applications and legacy phone systems. 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. 6. IANA Considerations This document makes no request of IANA. Bran & Jennings Expires December 30, 2011 [Page 5] Internet-Draft Abbreviated-Title June 2011 Note to RFC Editor: this section may be removed on publication as an RFC. 7. Security Considerations The codec requirements have no additional security considerations other than those captured in [I-D.ekr-security-considerations-for-rtc-web]. 8. Acknowledgements 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. 9. Normative References [I-D.ekr-security-considerations-for-rtc-web] Rescorla, E., "Security Considerations for RTC-Web", May 2011. [I-D.webm] Google, Inc., "VP8 Data Format and Decoding Guide", July 2010. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3551] Schulzrinne, H. and S. Casner, "RTP Profile for Audio and Video Conferences with Minimal Control", STD 65, RFC 3551, July 2003. [RFC4734] Schulzrinne, H. and T. Taylor, "Definition of Events for Modem, Fax, and Text Telephony Signals", RFC 4734, December 2006. Bran & Jennings Expires December 30, 2011 [Page 6] Internet-Draft Abbreviated-Title June 2011 Authors' Addresses Cary Bran Cisco 170 West Tasman Drive San Jose, CA 95134 USA Phone: +1 206 256-3502 Email: cbran@cisco.com Cullen Jennings Cisco 170 West Tasman Drive San Jose, CA 95134 USA Phone: +1 408 421-9990 Email: fluffy@cisco.com Bran & Jennings Expires December 30, 2011 [Page 7]