WebRTC Codec and Media Processing Requirements
draft-cbran-rtcweb-codec-01
The information below is for an old version of the document.
| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Authors | Cary Bran , Cullen Jennings | ||
| Last updated | 2011-10-29 (Latest revision 2011-07-01) | ||
| Replaced by | draft-ietf-rtcweb-audio, draft-ietf-rtcweb-video, draft-ietf-rtcweb-video, RFC 7874, RFC 7742 | ||
| Stream | (None) | ||
| Formats | plain text html xml htmlized pdfized bibtex | ||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | I-D Exists | |
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-cbran-rtcweb-codec-01
Network Working Group C. Bran
Internet-Draft Plantronics
Intended status: Standards Track C. Jennings
Expires: May 1, 2012 Cisco
October 29, 2011
WebRTC Codec and Media Processing Requirements
draft-cbran-rtcweb-codec-01
Abstract
This document outlines the codec and media processing requirements
for WebRTC 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,
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published except as an Internet-Draft.
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on May 1, 2012.
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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Codec Requirements . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Audio Codec Requirements . . . . . . . . . . . . . . . . . 3
3.2. Video Codec Requirements . . . . . . . . . . . . . . . . . 3
4. WebRTC Client Requirements . . . . . . . . . . . . . . . . . . 4
5. Legacy VoIP Interoperability . . . . . . . . . . . . . . . . . 5
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
7. Security Considerations . . . . . . . . . . . . . . . . . . . . 5
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5
9. Normative References . . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
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1. Introduction
An integral part of the success and adoption of the Web Real Time
Communications (WebRTC) will be the voice and video interoperability
between WebRTC applications. This specification will outline the
media processing and codec requirements for WebRTC client
implementations.
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 WebRTC
client applications. To ensure a baseline level of interoperability
between WebRTC clients, a minimum set of required codecs are
specified below. While this section specifies the codecs that will
be mandated for all WebRTC client implementations, it leaves the
question of supporting additional codecs to the will of the
implementer.
3.1. Audio Codec Requirements
WebRTC clients are REQUIRED to implement the following audio codecs.
o PCMA/PCMU - 1 channel with a rate of 8000 Hz and a ptime of 20 -
see section 4.5.14 of [RFC3551]
o Telephone Event - [RFC4734]
o Opus [draft-ietf-codec-opus]
3.2. Video Codec Requirements
If the MPEG-LA issues an intent to offer H.264 baseline profile on a
royalty free basis for use in browsers before March 15, 2012, then
the REQUIRED video codecs will be H.264 baseline. If this does not
happen by that the date, then the REQUIRED video codec will be VP8
[I-D.webm].
The following feature list applies to all required video codecs.
Required video codecs:
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o MUST support at least 10 frames per second (fps) and SHOULD
support 30 fps
o If VP8, then 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
4. WebRTC Client Requirements
It is plausible that the dominant near to mid-term WebRTC usage model
will be people using the interactive audio and video capabilities to
communicate with each other via web browsers running on 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 WebRTC compatible clients, functionality such as
automatic gain control, echo cancellation, headset detection and
passing call control events to connected devices 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 Ability to override automatic gain control to manually set gain
o Auto-adjustments to gain control and echo cancellation algorithms
based on if a headset or internal speakers/microphone is being
used
o Echo cancellation, including acoustic echo cancellation
o Headset detection
o Call control event notification to connected devices such as
headsets
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5. Legacy VoIP Interoperability
The codec requirements above will ensure, at a minimum, voice
interoperability capabilities between WebRTC client applications and
legacy phone systems.
Video interoperability will be dependent upon the MPEG-LA decision
regarding H.264 baseline.
6. IANA Considerations
This document makes no request of IANA.
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.
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[RFC4734] Schulzrinne, H. and T. Taylor, "Definition of Events for
Modem, Fax, and Text Telephony Signals", RFC 4734,
December 2006.
Authors' Addresses
Cary Bran
Plantronics
345 Encinial Street
Santa Cruz, CA 95060
USA
Phone: +1 206 661-2398
Email: cary.bran@plantronics.com
Cullen Jennings
Cisco
170 West Tasman Drive
San Jose, CA 95134
USA
Phone: +1 408 421-9990
Email: fluffy@cisco.com
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