Graphics Reference
In-Depth Information
When completed, AVC had about twice the compression capability of
MPEG-2—i.e., one could code video using only about half the bit rate while
still achieving the same level of quality—so that one could send twice as many
TV channels through a communication link or store twice as much video on a
disc without sacrificing quality. Alternatively, the improved compression capability
could be used to provide higher quality or enable the use of higher picture resolution
or higher frame rates than would otherwise be possible. AVC also emerged at
around the same time that service providers and disc storage format designers were
considering a transition to offer higher resolution “HDTV” rather than their prior
“standard definition” television services. Once system developers realized that they
needed to store and send twice as much data if they were going to use MPEG-2
instead of AVC for whatever video service they were trying to provide, most of
them decided they needed to find a transition path to AVC. While MPEG-2 video
remains a major presence today for legacy compatibility reasons, it is clearly fading
away in terms of importance.
HEVC offers the same basic value proposition today that AVC did when it
emerged—i.e., a doubling of compression capability. It can compress video about
twice as much as AVC without sacrificing quality, or it can alternatively be used to
enable delivery of higher resolutions and frame rates—or other forms of higher
quality, such as a higher dynamic range or higher precision for improved color
quality. It also comes at another time when new video services are emerging—this
time for UHDTV, higher dynamic range, and wider color gamut.
Compression capability—also known as “coding efficiency” or “compression
efficiency”—is the most fundamental driving force behind the adoption of modern
digital video compression technology, and HEVC is exceptionally strong in that
area. It is this meaning from which the High Efficiency Video Coding standard
derives its name. However, it is also important to remember that the standard
only provides encoders with the ability to compress video efficiently—it does not
guarantee any particular level of quality, since it does not govern whether or not
encoders will take full advantage of the capability of the syntax design (or whether
or not they will use that syntax for other purposes such as enhanced loss robustness).
1.3
Collaborative Development, Interoperability,
and Flexibility
As noted earlier, the HEVC standard was developed in an open process with very
broad participation. This helped to ensure that the design would apply generically
across a very broad range of applications, and that it was well studied and flexible
and would not contain quirky shortcomings that could have been prevented by
greater scrutiny during the design process.
Moreover, much of what can distinguish a good formal “standard” from simply
any particular well-performing technology product is the degree to which interop-
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