RTCWEB Working Group B. Burman
Internet-Draft Ericsson
Intended status: Standards Track M. Isomaki
Expires: April 09, 2014 Nokia
B. Aboba
Microsoft Corporation
G. Martin-Cocher
BlackBerry Ltd
G. Mandyam
Qualcomm Innovation Center
X. Marjou
Orange
C. Jennings
Cisco
D. Singer
Apple
October 06, 2013
H.264 as Mandatory to Implement Video Codec for WebRTC
draft-burman-rtcweb-h264-proposal-02
Abstract
This document proposes that, and motivates why, H.264 should be a
Mandatory To Implement video codec for WebRTC.
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
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and may be updated, replaced, or obsoleted by other documents at any
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This Internet-Draft will expire on April 09, 2014.
Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. H.264 Overview . . . . . . . . . . . . . . . . . . . . . . . 3
4. Implementations . . . . . . . . . . . . . . . . . . . . . . . 3
5. Licensing . . . . . . . . . . . . . . . . . . . . . . . . . . 4
5.1. Royalty Free for Innovation, Low-volume Shipments . . . . 4
5.2. Higher H.264/AVC Profile Tools Bundled . . . . . . . . . 5
5.3. Licensing Stability . . . . . . . . . . . . . . . . . . . 5
6. Performance . . . . . . . . . . . . . . . . . . . . . . . . . 6
7. Profile/level . . . . . . . . . . . . . . . . . . . . . . . . 8
8. Negotiation . . . . . . . . . . . . . . . . . . . . . . . . . 9
9. Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
11. Security Considerations . . . . . . . . . . . . . . . . . . . 11
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
13.1. Normative References . . . . . . . . . . . . . . . . . . 11
13.2. Informative References . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction
The selection of a Mandatory To Implement (MTI) video codec for
WebRTC has been discussed for quite some time in the RTCWEB WG. This
document proposes that the H.264 video codec should be mandatory to
implement for WebRTC implementations and gives motivation to this
proposal.
The core of the proposal is that:
H.264 Constrained Baseline Profile Level 1.2 MUST be supported as
Mandatory To Implement video codec.
To enable higher quality for devices capable of it:
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H.264 Constrained High Profile Level 1.3, extended to support 720p
resolution at 30 Hz framerate is RECOMMENDED.
This draft discusses the advantages of H.264 as the authors of this
draft see them; a richness of implementations and hardware support,
well known licensing conditions, good performance, and well defined
handling of varying device capabilities.
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 BCP 14, RFC 2119
[RFC2119].
3. H.264 Overview
The video coding standard Advanced Video Coding (ITU-T H.264 | ISO/
IEC 14496-10 [H264]) has been around for almost ten years by now.
Developed jointly by MPEG and ITU-T in the Joint Video Team, it was
published in its first version in 2003 and amended with support for
higher-fidelity video in 2004. Other significant updates include
support for scalability (2007) and multiview (2009). The codec goes
under the names H.264, AVC and MPEG-4 Part10. In this memo the term
"H.264" will be used.
H.264 was from the start very successful and has become widely
adopted for (video) content as well as (video) communication services
worldwide.
H.264 is mandatory in mobile wireless standards for multimedia
telephony and packet switched streaming. It is also the leading de
facto standard for web video content delivered in HTML5 or other
technologies, and is supported in all major web browsers, mobile
device platforms, and desktop operating systems.
4. Implementations
Arguably, hardware or DSP acceleration for video encoding/decoding
would be mostly beneficial for devices that has relatively lower
capacity in terms of CPU and power (smaller batteries), and the most
common devices in this category are phones and tablets. There is a
long list of vendors offering hardware or DSP implementations of
H.264. In particular all vendors of platforms for mobile high-range
phones, smartphones, and tablets support H.264/AVC High Profile
encoding and decoding at least 1080p30, but those platforms are
currently in general not used for low- to mid-range devices. These
vendors are Qualcomm, TI, Nvidia, Renesas, Mediatek, Huawei
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Hisilicon, Intel, Broadcom, Samsung. Those platforms all support
H.264/AVC codec with dedicated HW or DSP. The majority of the
implementations also support low-delay real-time applications.
There are also other specifications that implement support for H.264,
such as HDMI(TM).
Regarding software implementations there is a long list of available
implementations. Wikipedia provides an illustration of this with
their list [Implementations], and more implementations appear, e.g. a
royalty-free open source implementation from Polycom including H.264/
SVC support [Woon]. Microsoft has produced an H.264 prototype for
use in browsers [CURtcWeb]. Not only are there standalone
implementations available, including open source, but in addition
recent Windows and Mac OS X versions support H.264 encoding and
decoding.
The WebM wiki [WEBM] shows only 3 (out of ~37) ARM SoCs which support
VP8 encode and decode. All (~37) support H.264. This only
represents a fraction of deployed SoCs. Almost all deployed SoCs, as
well as future designs, support H.264 encode and decode, including
desktop (Intel x86) chipsets.
The benefits of hardware encoder and decoder implementations
typically have an order of magnitude or more performance advantage
(e.g., 1080p versus 360p becomes achievable) and power savings (e.g.,
tens of milliwatts versus many hundreds of milliwatts or even watts
are consumed just by the encoder and decoder). While VP8 proponents
have argued codec power is not a major concern relative to displays,
this neglects the advances in display technology that put the central
processor back near the top power consumers.
5. Licensing
5.1. Royalty Free for Innovation, Low-volume Shipments
MPEG-LA released their AVC Patent Portfolio License already in 2004
and in 2010 they announced that H.264 encoded Internet video is free
to end users will never be charged royalties [MPEGLA]. Real-time
generated content, the content most applicable to WebRTC, was free
already from the establishment of the MPEG-LA license
[MPEGLA-License]. License fees for products that decode and encode
H.264 video remain though. Those fees [MPEGLA-Terms] are, and will
very likely continue to be for the lifetime of MPEG-LA pool, $0.20
per codec or less.
To paraphrase, the MPEG LA license does allow up to 100K units per
year, per legal entity/company (type "a" sublicensees in MPEG LA's
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definition), to be shipped for zero ($0) royalty cost. This should
be adequate for many WebRTC innovators or start-ups to try out new
implementations on a large set of users before incurring any patent
royalty costs, a benefit to selecting a H.264/AVC profile as the
mandatory codec.
5.2. Higher H.264/AVC Profile Tools Bundled
It should be noted that when one licenses the MPEG LA H.264/AVC pool,
patents for higher profile tools - such as CABAC, 8x8 - are bundled
in with those required for the Constrained Baseline Profile. Thus,
these could optionally be used by WebRTC implementers to achieve even
greater performance or efficiencies than using H.264 Constrained
Baseline Profile alone.
It can also be noted that for MPEG-LA, since one license covers both
an encoder and decoder, there is no additional cost of using an
encoder to an implementation that supports decoding of H.264.
5.3. Licensing Stability
H.264 is a mature codec with a mature and well-known licensing model.
It is a well-established fact that not all H.264 right holders are
MPEG-LA pool members. H.264 is however an ITU/ISO/IEC international
standard, developed under their respective patent policies, and all
contributors must license their patents under Reasonable And Non-
Discriminatory (RAND) terms. In the field of video coding, most
major research groups interested in patents do contribute to the ITU/
ISO/IEC standards process and are therefore bound by those terms.
VP8 is a much younger codec than H.264 and it is fair to say that the
licensing situation is less clear than for H.264. Google has
provided their patent rights on VP8, including patents owned by 11
patent holders [MpegLaVp8], under a open source friendly license with
very restrictive reciprocity conditions.
Recently, VP8 was adopted as Working Draft for Video Coding for
Browsers in MPEG, which is the first step in becoming an MPEG
standard. As such, it will have to follow the ISO/IEC/ITU common
patent policy [IsoIecItuPolicy], but IPR statements cannot be
expected there for still some time. There is no guarantee that IPR
statements in MPEG will be royalty free (option 1), but may just as
well be "Fair, Reasonable And Non-Discriminatory" (FRAND, option 2).
This indicates that the licensing situation for VP8 has still not
settled.
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6. Performance
Comparing video quality is difficult. Practically no modern video
encoding method includes any bit-exact encoding where a given (video)
input produces a specified encoded output bitstream. Instead, the
encoded bitstream syntax and semantics are specified such that a
decoder can correctly interpret it and produce a known output. This
is true both for H.264 and VP8. Significant freedom is left to the
encoder implementation to choose how to represent the encoded video,
for example given a specific targeted bitrate. Thus it cannot in
general be expected that any encoded video bitstream represents the
best possible or most efficient representation, given the defined
bitstream syntax elements available to that codec. The actually
achieved quality for a certain bitstream, how close it is to the
optimally possible with available syntax, at any given bitrate rather
depends on the performance of the individual encoder implementation.
Also, not only is the resulting experienced video quality subjective,
but also depends on the source material, on the point of operation
and a number of other considerations. In addition, performance can
be measured vs. bitrate, but also vs. e.g. complexity - and here
another can of worms can be opened because complexity depends on
hardware used (some platforms have video codec accelerations), SW
platform (and how efficient it can use the hardware) and so on. On
top of this comes that different implementations can have different
performance, and can be operated in different ways (e.g. tradeoffs
between complexity and quality can be made). Regardless of how a
performance evaluation is carried out it can always be said that it
is not "fair". This section nevertheless attempts to shed some light
on this subject, and specifically the performance (measured against
bitrate) of H.264 compared to VP8.
A number of studies [H264perf1][H264perf2][H264perf3] have been made
to compare the compression efficiency performance between H.264 and
VP8. These studies show that H.264 is in general performing better
than VP8 but the studies are not specifically targeting video
conferencing.
Google made a comparison test between VP8 and H.264 [GooglePSNR],
providing a set of test scripts [GoogleScripts]. That test includes
the use of rate control for both codecs. We believe this to be a
comparison problem since rate control is part of the encoder, which
as said above is typically not specified in video codec standards but
left up to individual implementations. The quantization parameter
(qp) level affects the rate/distortion tradeoff in video coding.
Comparing using fixed qp-levels is what has typically been used when
benchmarking new codecs, for example when benchmarking HEVC [H265]
against H.264 in the JCT-VC [JCT-VC] standardization. We are going
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to select a codec (essentially bit stream format), not a rate control
mechanism; once the codec is selected you can choose whatever rate
control mechanism you wish that best suits your specific application.
Therefore, we propose to compare the codecs with rate control off,
using fixed quantization parameter (qp) levels.
Ericsson made a comparison using Google's published test scripts as
baseline and changed the parameter settings in order to make it
possible to measure using fixed qp. The focus of that test was to
evaluate the best compression efficiency that could be achieved with
both codecs since it was believed to be harder to make a fair
comparison trying to use complexity constraints. We used the same
eleven sequences as in the previous Google test, but limited them to
the first 10 seconds since they varied from 10 seconds to minutes;
this also eased computation time. The used video resolutions are
640x360 @ 30 fps, 640x480 @ 30 fps, 1280x720 @ 30 fps and 1280x720 @
50 fps.
We used two H.264 encoder implementations:
o X264, which is an open-source codec that can operate in everything
from real-time to slow
o JM, which is the (Joint Model) reference implementation that was
used to develop H.264, and is very slow but attempts to be very
efficient in terms of bits per quality
This is a summary of the results (complete scripts and results
available here [H264VP8Tests]):
+--------------------------------+----------------------------------+
| Test | Resulting bitrate at equivalent |
| | quality |
+--------------------------------+----------------------------------+
| X264 Constrained Baseline vs | H.264 wins with 1% |
| VP8 | |
| JM Constrained Baseline vs VP8 | H.264 wins with 4% |
| X264 Constrained High vs VP8 | H.264 wins with 25% |
| JM Constrained High vs VP8 | H.264 wins with 24% |
+--------------------------------+----------------------------------+
Table 1: Performance Comparison Results
It is interesting to note that the measurements are more stable in
this test; the variance of the percentages for the different
sequences is now around 70, down from around 700 in Google's test.
We believe this is due to the removal of the rate controller, which
acts as noise on the measurements.
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It can also be noted that the Google method of calculating the rate
differences does not give exactly the same numbers as the JCT-VC way
of calculating Bjontegaard Delta bitrate (BD-rate) [PSNRdiff]. The
main difference is that the JM score for Constrained High in the
table above (Table 1) is around 29% better than VP8 if the JCT-VC way
of calculating BD-rate is used.
A rough complexity estimate can be obtained from the total running
times for the tests:
o X264: 1 hour 3 minutes
o VP8: 2 hours 0 minutes
o JM: An order of magnitude slower
Again, video quality is difficult to compare. The authors however
believe that the data provided in this section shows that H.264
Constrained Baseline is at least on par with VP8, while H.264
Constrained High seems to have a clear quality advantage. As a final
note, the new H.265/HEVC standard [H265] clearly outperforms all
three, but the authors think it is premature to mandate HEVC for
WebRTC.
7. Profile/level
H.264/AVC [H264] has a large number of encoding tools, grouped in
functionally reasonable toolsets by codec profiles, and a wide range
of possible implementation capability and complexity, specified by
codec levels. It is typically not reasonable for H.264 encoders and
decoders to implement maximum complexity capability for all of the
available tools. Thus, any H.264 decoder implementation is typically
not able to receive all possible H.264 streams. Which streams can be
received is described by what profile and level the decoder conforms
to. Any video stream produced by an H.264 encoder must keep within
the limits defined by the intended receiving decoder's profile and
level to ensure that the video stream can be correctly decoded.
Profiles can be "ranked" in terms of the amount of tools included,
such that some profiles with few tools are "lower" than profiles with
more tools. However, profiles are typically not strictly supersets
or subsets of each other in terms of which tools are used, so a
strict ranking cannot be defined. It is also in some cases possible
to express compliance to the common subset of tools between two
different profiles. This is fairly well described in [RFC6184].
When choosing a Mandatory To Implement codec, it is desirable to use
a profile and level that is as widely supported as possible.
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Therefore, H.264 Constrained Baseline Profile Level 1.2 MUST be
supported as Mandatory To Implement video codec. This is possible to
support with significant margin in hardware devices (Section 4) and
should likely also not cause performance problems for software-only
implementations. All Level definitions (Annex A of [H264]) include a
maximum framesize in macroblocks (16*16 pixels) as well as a maximum
processing requirement in macroblocks per second. That number of
macroblocks per second can be almost freely distributed between
framesize and framerate. The maximum framesize for Level 1.2
corresponds to 352*288 pixels (CIF). Examples of allowed framesize
and framerate combinations for Level 1.2 are CIF (352*288 pixels) at
15 Hz, QVGA (320*240 pixels) at 20 Hz, and QCIF (176*144 pixels) at
60 Hz.
Recognizing that while the above profile and level will likely be
possible to implement in any device, it is also likely not sufficient
for applications that require higher quality. Therefore, it is
RECOMMENDED that devices and implementations that can meet the
additional requirements also implement at least H.264 Constrained
High Profile Level 1.3, extended to support 720p resolution at 30 Hz
framerate, but the extension MAY alternatively be made from any Level
higher than 1.3.
Note that the lowest non-extended Level that support 720p30 is Level
3.1, but fully supporting Level 3.1 also requires fairly high
bitrate, large buffers, and other encoding parameters included in
that Level definition that are likely not reasonable for the targeted
communication scenario. This method of extending a lower level in
SDP (Section 8) with a smaller set of applicable parameters is fully
in line with [RFC6184], and is already used by some video
conferencing vendors.
When considering the main WebRTC use case, real-time communication,
the lack of need to support interlaced image format in that context,
the limited use of and added delay from bi-directionally predicted
(B) pictures, and the added implementation and computation complexity
that comes with interlace and B-picture handling suggests that
Constrained High Profile should be preferred over High Profile as
optional codec. Note also that while Constrained High Profile is
currently less supported in devices than High Profile, any High
Profile decoder will be capable of decoding a Constrained High
Profile bitstream since it is a subset of High Profile. To make a
High Profile encoder support Constrained High Profile encoding, it
will have to turn off interlace encoding and turn off the use of bi-
directional prediction.
8. Negotiation
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Given that there exist a fairly large set of defined profiles and
levels (Section 7) in the H.264 specification, the probability is
rather low that randomly chosen H.264 encoder and decoder
implementations have exactly matching capabilities. In any
communication scenario, there is therefore a need for a decoder to be
able to convey its maximum supported profile and level that the
encoder must not exceed.
In addition and depending on the wanted use case and the conditions
that apply at a certain communication instance, there may also be a
need to describe the currently wanted profile and level at the start
of the communication session, which may be lower than the maximum
supported by the implementation. In this scenario it may also be of
interest to communicate from the encoder to the decoder both which
profile and level that will actually be used and what is the maximum
supported profile and level. The reason to communicate not only the
starting point but also the maximum assumes that communication
conditions may change during the conditions, maybe multiple times,
possibly making another profile and level be a more appropriate
choice.
Communication of maximum supported profile and level is the only
mandatory SDP [RFC4566] parameter in the H.264 payload format
[RFC6184], which also includes a large set of optional parameters,
describing available use (decoder) and intended use (encoder) of
those parameters for a specific offered [RFC3264] stream.
If the above mentioned (Section 7) capability for 720p30 is supported
as an extension to Constrained High Profile Level 1.3 (or higher),
the level extension SHOULD be signaled in SDP using the following
parameters as defined in section 8.1 of [RFC6184]:
o profile-level-id=640c0d (or corresponding to a higher Level of
Constrained High profile)
o max-fs=3600 (or greater)
o max-mbps=108000 (or greater)
o max-br=768 (or greater, whatever the device implementation can
support)
9. Summary
H.264 is widely adopted and used for a large set of video services.
This in turn is because H.264 offers great performance, reasonable
licensing terms (and manageable risks). As a consequence of its
adoption for many services, a multitude implementations in software
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and hardware are available. Another result of the widespread
adoption is that all associated technologies, such as payload
formats, negotiation mechanisms and so on are well defined and
standardized. In addition, using H.264 enables interoperability with
many other services without video transcoding.
We therefore propose to the WG that H.264 shall be mandatory to
implement for all WebRTC endpoints that support video, according to
the details described in Section 7 and Section 8.
10. IANA Considerations
This document makes no request of IANA.
Note to RFC Editor: this section may be removed on publication as an
RFC.
11. Security Considerations
No specific considerations apply to the information in this document.
12. Acknowledgements
All that provided valuable descriptions, comments and insights about
the H.264 codec on the IETF mailing lists.
13. References
13.1. Normative References
[H264] ITU-T Recommendation H.264, "Advanced video coding for
generic audiovisual services", April 2013,
<http://www.itu.int/rec/T-REC-H.264-201304-I>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model
with Session Description Protocol (SDP)", RFC 3264, June
2002.
[RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
Description Protocol", RFC 4566, July 2006.
[RFC6184] Wang, Y., Even, R., Kristensen, T., and R. Jesup, "RTP
Payload Format for H.264 Video", RFC 6184, May 2011.
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13.2. Informative References
[CURtcWeb]
Microsoft Open Technologies, Inc., "CU-RTC-Web-Video",
July 2013, <http://html5labs.interoperabilitybridges.com/
prototypes/cu-rtc-web-video/cu-rtc-web-video/info>.
[GooglePSNR]
The WebM Project, "VP8 Results", April 2013, <http://
downloads.webmproject.org/ietf_tests/
vp8_vs_h264_quality.html>.
[GoogleScripts]
The WebM Project, "VP8 vs H.264 Test Scripts", April 2013,
<http://downloads.webmproject.org/ietf_tests/
vp8_vs_h264.tar.xz>.
[H264VP8Tests]
Ericsson, "More H.264 vs VP8 tests", June 2013, <http://
www.ietf.org/mail-archive/web/rtcweb/current/
zipDGJUJ9JZ8n.zip>.
[H264perf1]
Vatolin, D., "MPEG-4 AVC/H.264 Video Codecs Comparison
2010 - Appendixes", , May 2010, <http://
compression.graphicon.ru/video/codec_comparison/h264_2010/
appendixes.html#Appendix_8>.
[H264perf2]
Shah, K., "Implementation, performance analysis and
comparison of VP8 and H.264.", University of Texas at
Arlington Department of Electrical Engineering, 2011,
<http://www-ee.uta.edu/Dip/Courses/EE5359/
2011SpringFinalReportPPT/
Shah_EE5359Spring2011FinalPPT.pdf>.
[H264perf3]
De Simone, F., Goldmann, L., Lee, J., and T. Ebrahimi,
"Performance analysis of VP8 image and video compression
based on subjective evaluations", Ecole Polytechnique
F'd'rale de Lausanne (EPFL) , Aug 2011, <http://
infoscience.epfl.ch/record/168259/files/article.pdf>.
[H265] ITU-T Recommendation H.265, "High Efficiency Video
Coding", April 2013,
<http://www.itu.int/rec/T-REC-H.265-201304-I>.
[Implementations]
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Wikipedia, ., "H.264/MPEG-4 AVC products and
implementations", October 2012, <http://en.wikipedia.org/
wiki/H.264/MPEG-4_AVC_products_and_implementations>.
[IsoIecItuPolicy]
ISO, "ISO/IEC/ITU common patent policy", April 2007,
<http://isotc.iso.org/livelink/livelink/fetch/2000/2122/
3770791/Common_Policy.htm>.
[JCT-VC] ITU-T, "JCT-VC - Joint Collaborative Team on Video
Coding", , <http://www.itu.int/en/ITU-T/studygroups/
2013-2016/16/Pages/video/jctvc.aspx>.
[MPEGLA-License]
MPEG LA, "AVC Patent Portfolio License Briefing", May
2009, <http://www.mpegla.com/main/programs/avc/Documents/
avcweb.pdf>.
[MPEGLA-Terms]
MPEG LA, "SUMMARY OF AVC/H.264 LICENSE TERMS", , <http://
www.mpegla.com/main/programs/avc/Documents/
AVC_TermsSummary.pdf>.
[MPEGLA] MPEG LA, "MPEG LAs AVC License Will Not Charge Royalties
for Internet Video that is Free to End Users through Life
of License", MPEGLA News Release, August 2010,
<www.mpegla.com/Lists/MPEG%20LA%20News%20List/Attachments/
231/n-10-08-26.pdf>.
[MpegLaVp8]
O'Reilly, T., "Google and MPEG LA Announce Agreement
Covering VP8 Video Format", March 2013, <http://
www.mpegla.com/Lists/MPEG%20LA%20News%20List/Attachments/
88/n-13-03-07.pdf>.
[PSNRdiff]
Bjontegaard, G., "Calculation of Average PSNR Differences
between RD-Curves", ITU-T SG16 Q.6 Document VCEG-M33,
April 2001.
[WEBM] The WebM Project, "ARM SoCs", ,
<http://wiki.webmproject.org/hardware/arm-socs>.
[Woon] Polycom, "Polycom Delivers Open Standards-Based Scalable
Video Coding (SVC) Technology, Royalty-Free to Industry",
October 2012, <http://www.polycom.com/content/www/en/
company/news/press-releases/2012/20121004.html>.
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Authors' Addresses
Bo Burman
Ericsson
Farogatan 6
Stockholm 16480
Sweden
Email: bo.burman@ericsson.com
Markus Isomaki
Nokia
Keilalahdentie 2-4
Espoo FI-02150
Finland
Email: markus.isomaki@nokia.com
Bernard Aboba
Microsoft Corporation
One Microsoft Way
Redmond, WA 98052
US
Email: bernard_aboba@hotmail.com
Gaelle Martin-Cocher
BlackBerry Ltd
1875 Buckhorn Gate
Mississauga, ON L4W 5P1
Canada
Email: gmartincocher@blackberry.com
Giri Mandyam
Qualcomm Innovation Center
Email: mandyam@quicinc.com
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Xavier Marjou
Orange
2, avenue Pierre Marzin
Lannion 22307
France
Email: xavier.marjou@orange.com
Cullen Jennings
Cisco
170 West Tasman Drive
San Jose, CA 95134
United States
Email: fluffy@cisco.com
David Singer
Apple
Email: singer@apple.com
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