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Network Working Group                                      H. Alvestrand
Internet-Draft                                                 A. Grange
Intended status: Informational                                    Google
Expires: August 29, 2013                               February 25, 2013


                  VP8 as RTCWEB Mandatory to Implement
                     draft-alvestrand-rtcweb-vp8-01

Abstract

   This document recommends that the RTCWEB working group choose the VP8
   specification as a mandatory to implement video codec for RTCWEB
   implementations.

   This document is not intended for publication as an RFC.

Requirements Language

   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].

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   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 August 29, 2013.

Copyright Notice

   Copyright (c) 2013 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



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   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.


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Requirements for an MTI codec . . . . . . . . . . . . . . . . . 3
   3.  Definition of VP8 . . . . . . . . . . . . . . . . . . . . . . . 3
   4.  Image quality evaluations . . . . . . . . . . . . . . . . . . . 3
   5.  Performance evaluation  . . . . . . . . . . . . . . . . . . . . 4
     5.1.  Software  . . . . . . . . . . . . . . . . . . . . . . . . . 4
     5.2.  Hardware support  . . . . . . . . . . . . . . . . . . . . . 4
     5.3.  Hardware performance  . . . . . . . . . . . . . . . . . . . 5
   6.  IPR status  . . . . . . . . . . . . . . . . . . . . . . . . . . 5
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
   8.  Security Considerations . . . . . . . . . . . . . . . . . . . . 6
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 6
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . . . 6
     10.1. Normative References  . . . . . . . . . . . . . . . . . . . 6
     10.2. Informative References  . . . . . . . . . . . . . . . . . . 7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 7

























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1.  Introduction

   As described in [I-D.ietf-rtcweb-overview], successful interoperable
   deployment of RTCWEB requires that implementations share a video
   codec.  Not requiring a video codec will mean that this decision is
   left to processes outside the standards process, and risks the
   spectre of fragmented deployment.

   This memo argues that VP8 should be that codec.


2.  Requirements for an MTI codec

   As outlined by the presentation given at the IETF meeting at IETF 84
   in Vancouver, it is unclear what the hard requirements for a video
   codec are, but the items that it was suggested that proposals give
   information on were:

   o  Image quality - comparative data was sought, but without defining
      a baseline

   o  Performance - what resolutions / frame rates can be achieved in
      software on some common systems

   o  Power consumption of hardware and/or software implementations

   o  Hardware support

   o  IPR status

   This document lays out the available information in each category.


3.  Definition of VP8

   VP8 is defined in [RFC6386], and its RTP payload is defined in
   [I-D.ietf-payload-vp8] .  There are no profiles; all decoders are
   able to decode all valid media streams.


4.  Image quality evaluations

   In tests carried out by Google on a set of ten sample video clips
   containing typical video-conference content, VP8 outperformed the
   x264 H.264 codec running the constrained baseline profile by on
   average 37.2%.  That is, at the same quality, measured by PSNR, VP8
   produced 37.2% fewer bits on average than H.264.  VP8 outperformed
   H.264 on all ten of the test clips by between 19% and 64%.  Both



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   codecs were configured in one-pass mode using settings conducive to
   real-time operation, and the ten clips varied in size between 640x360
   pixels and 1280x720 pixels.

   An independent evaluation by Christian Feller and Mohammed Raad,
   presented to ISO/IEC SC29 WG11 in July 2012, showed that VP8
   performed better than the (H.264 baseline) anchors for the IVC
   project on a majority of the cases.

   As part of the process of submitting VP8 for evaluation in ISO/IEC
   JTC1 SC29 WG11 (MPEG), Google is also commissioning an independent
   subjective quality evaluation effort.


5.  Performance evaluation

5.1.  Software

   The current reference implementation is libvpx, developed in the WebM
   project.

   The encoding speed in software depends on the quality setting.  On a
   stock PC platform using an Intel Xeon CPU at 2.67 GHz, in a test
   using extremely difficult 720p material and encoding at a target data
   rate of 2 Mbit/sec, VP8's encoding speed varied from 48.4 fps (at the
   setting used in WebRTC today) to 96.2 fps (at the fastest setting),
   using a single thread.  This variation in encode speed is achieved by
   changing the configuration of VP8 encoding tools in a deterministic
   way to trade-off encoding speed with output quality.

   On a stock PC platform using an Intel Xeon CPU with 8 cores at
   2.27GHz, tests using difficult 720p material encoded at 2 Mbit/sec
   show that using a single thread VP8 can decode at 200.50 fps (in
   comparison H.264, baseline profile, achieves 107.95 fps), using four
   threads VP8 decodes at 519.96 fps (H.264 achieves 363.73 fps), and
   using sixteen threads VP8 decodes at 1,076.49 fps (H.264 achieves
   807.11 fps). .

5.2.  Hardware support

   To date, Google has licensed VP8 hardware accelerators to over 50
   chip manufacturers, and VP8 hardware IP cores have also been made
   available by Imagination Technologies, Verisilicon and Chips & Media.
   Furthermore, Google is aware of several 3rd party implementations of
   VP8 decoders and encoders from the world's leading semiconductor
   companies.

   At the time of this writing, more than a dozen of chip manufacturers



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   have announced chips with 1080p VP8 support, including Samsung
   (Exynos 5), NVIDIA (Tegra 3), Marvell (Armada 1500), Broadcom
   (BCM28150), Texas Instruments (OMAP54xx), Freescale (i.MX 6), ST-
   Ericsson (NovaThor L9540), LG Electronics, Hisilicon (K3v2), Rockchip
   (RK2918, RK3066), Nufront (NS115), Ziilabs (ZMS40) and Allwinner
   (A10).  Google estimates that a clear majority of leading mobile
   chipsets in 2013 will contain VP8 hardware support.

   The encoder chip produced by Quanta has allowed OEMs to integrate
   hardware HD VP8 encoding into their video camera hardware; this chip
   is available now.  More suppliers have such a chip coming.

5.3.  Hardware performance

   Several of the aforementioned hardware implementations are based on
   the WebM video hardware designs described at
   http://www.webmproject.org/hardware/.  Performance figures include:

   o  Decode of 1080p video at 30 fps at less than 100 MHz clock
      frequency

   o  Decoding more than ten simultaneous SD video streams on a single
      chip

   o  Less than 25 milliwatts of power for 1080p decoding

   o  Encoding 1080p video at 30 fps at less than 220 MHz clock
      frequency

   o  Less than 80 milliwatts of power for HD video encoding

   Based on the Hantro G1 multiformat decoder implementation, the VP8
   hardware decoder is 45% smaller in silicon area than the H.264 High
   Profile decoder.  VP8 also requires 18% less DRAM bandwidth than
   H.264 as it does not use bidirectional inter prediction, allowing
   significant reductions in the overall decoding system power
   consumption.


6.  IPR status

   Google has made its position clear with respect to Google-owned IPR
   in its licensing terms,
   http://www.webmproject.org/license/additional/.

   As of this moment (October 5, 2012), Google's royalty-free license
   commitment is the only IPR statement filed against RFC 6386 in the
   IETF disclosures database.



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   Google has also submitted VP8 for consideration in ISO/IEC JTC1 SC29
   WG11 (MPEG), in the IVC project (which aims for a royalty-free
   codec), and expects ISO to execute its ordinary process for
   resolution of IPR issues.


7.  IANA Considerations

   This document makes no request of IANA.

   Note to RFC Editor: this section may be removed on publication as an
   RFC.


8.  Security Considerations

   Codec definitions do not in themselves comprise security risks, as
   long as there is no means of embedding active content in their
   datastream.  VP8 does not contain such active content.

   Codec implementations have frequently been the cause of security
   concerns.  The reference implementation of VP8 has been extensively
   tested by Google security experts, and is believed to be free from
   exploitable vulnerabilities.  There is a continuous program in place
   to ensure that any vulnerabilities identified are repaired as quickly
   as possible.


9.  Acknowledgements

   Several members of the Google VP8 team contributed to this memo.


10.  References

10.1.  Normative References

   [I-D.ietf-payload-vp8]
              Westin, P., Lundin, H., Glover, M., Uberti, J., and F.
              Galligan, "RTP Payload Format for VP8 Video",
              draft-ietf-payload-vp8-08 (work in progress),
              January 2013.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC6386]  Bankoski, J., Koleszar, J., Quillio, L., Salonen, J.,
              Wilkins, P., and Y. Xu, "VP8 Data Format and Decoding



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              Guide", RFC 6386, November 2011.

10.2.  Informative References

   [I-D.ietf-rtcweb-overview]
              Alvestrand, H., "Overview: Real Time Protocols for Brower-
              based Applications", draft-ietf-rtcweb-overview-05 (work
              in progress), December 2012.


Authors' Addresses

   Harald Alvestrand
   Google
   Kungsbron 2
   Stockholm,   11122
   Sweden

   Email: harald@alvestrand.no


   Adrian Grange
   Google
   1950 Charleston Road
   Mountain View, CA  94043
   USA

   Phone:
   Fax:
   Email: agrange@google.com
   URI:




















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