Graphics Reference
In-Depth Information
to establish the picture resolution, frame rate, bit rate, buffering capacity, and other
aspects that are matters of degree rather than basic feature sets. For HEVC, the
lowest levels have only low resolution and low frame rate capability—e.g., a typical
video format for level 1 may be only 176
144 resolution at 15 frames per second,
whereas level 4.1 would be capable of 1920
1080 HDTV at 60 frames per second,
and levels in version 1 are defined up to level 6.1, which is capable of 8192
4320
video resolution at up to 120 frames per second.
However, when defining the levels of HEVC, a problem was encountered
between the demands of consumer use and those of professional use for similar
picture resolutions and frame rates. In professional environments, much higher bit
rates are needed for adequate quality than what would be necessary for consumer
applications. The solution for this was to introduce the concept of “tiers”. Several
levels in HEVC have both a Main tier and a High tier of capability specified, based
on the bit rates they are capable of handling.
1.6
Patent Rights Licensing
The consideration of a modern video coding design would be incomplete without
some understanding of the costs of the patent rights needed to use it. Digital video
technology is a subject of active research, investment, and innovation, and many
patents have been filed on advances in this field.
The international standardization organizations have patent policies that require
that technology cannot be included in a standard if the patent rights that are essential
to its implementation are known to not be available for licensing to all interested
parties on a world-wide basis under “reasonable and non-discriminatory” (RAND)
licensing terms. The idea behind this is that anyone should be able to implement an
international standard without being forced to agree to unreasonable business terms.
In other respects, the major standardization bodies generally do not get involved
in the licensing details for necessary patent rights—these are to be negotiated
separately, between the parties involved, outside the standardization development
process.
In recent history—e.g., for both AVC and MPEG-2, multiple companies have
gotten together to offer “pooled” patent licensing as a “one-stop shop” for licens-
ing the rights to a large number of necessary patents. A pool for HEVC patent
licensing has also recently begun to be formed and has announced preliminary
licensing terms. However, it is important for the community to understand that the
formation of such a pool is entirely separate from the development of the standard
itself. Patent holders are not required to join a pool, and even if they choose to join
a pool, they may also offer licenses outside the pool as well—as such pools are
non-exclusive licensing authorities. And licensees are thus not required to get their
licensing rights through such a pool and can seek any rights that are required on a
bilateral basis outside of the pool.
