Introduction - Advanced Video Coding Systems - page 13

The history of the VPx family can go back to a codec company On2 Technologies.
VP8 was first released by On2 in September 2008, replacing its predecessor VP7.
After Google acquired On2 in February 2010, calls for Google to release the VP8
source code were made. InMay 2010, Google released the VP8 codec software under
a BSD-like license and the VP8 bitstream format specification under an irrevocable
free patent license. In June 2010, Google amended the VP8 codec software license
to the 3-clause BSD license after some contention over whether the original license
was actually open source.
In February 2011, MPEG LA invited patent holders to identify patents that may
be essential to VP8 in order to form a joint VP8 patent pool. As a result, in March
the United States Department of Justice (DoJ) started an investigation into MPEG
LA for its role in possibly attempting to stifle competition. In July 2011, MPEG LA
announced that 12 patent holders had responded to its call to form a VP8 patent
pool, without revealing the patents in question, and despite On2 having gone to
great lengths to avoid such patents. In November 2011, the Internet Engineering
Task Force published the informational RFC 6386, VP8 Data Format, and Decoding
Guide. In March 2013, MPEG LA announced that it had dropped its effort to form
a VP8 patent pool after reaching an agreement with Google to license the patents
that it alleges “may be essential” for VP8 implementation, and granted Google the
right to sub-license these patents to any third-party user of VP8 or VP9. This deal
has cleared the way for possible MPEG standardization as its royalty-free Internet
video codec, after Google submitted VP8 to the MPEG committee in January 2013.

1.3.8 Timeline of Video Coding Standards

1.4 About This Topic

The rest of the topic is organized as follows:

• Chapter 2 gives a brief introduction of some basic concepts about video coding,

including color space, conversion among typical color spaces, video format, video
coding tools, and quality measurement. Moreover, the history and the development
of each concept are also provided. In fact, all the concepts are not independent but
closely related with each other, which will be found in this chapter.

• Chapter 3 gives an overview of the AVS2 standard, including the coding frame-

work, main coding tools, and syntax structure. It would help the reader understand
the AVS2 standard specification.

• Chapters 4 , 5 , 6 , and 7 introduce the key technologies used in AVS2 standard,

including prediction coding, transform coding, entropy coding, and loop filter.
Some specially designed coding technologies are adopted to improve the coding
performance based on the coding framework of AVS2. Chapter 4 introduces the
prediction technology including multiple-direction intraprediction and interpre-
diction with flexible reference frame management. Chapter 5 describes the large