Game Development Reference
In-Depth Information
Chapter 4
Prediction Coding
This chapter introduces the prediction coding tools of AVS2 standard, which consists
of five parts. The first part provides a brief introduction to the related works of
prediction coding. The following two parts detail two major prediction coding tools
of AVS2, known as intraprediction and interprediction. The fourth part introduces
the reference picture management scheme in AVS2, which plays an important role
in interprediction. The last part concludes the chapter.
4.1 Related Works
Prediction coding explores the temporal or spatial redundancy of the information
source by using the information already coded to predict the information to be coded,
so as to decrease the coding bits dramatically. And in 1952, Cutler, etc., from Bell
Lab invented the differential pulse codemodulation (DPCM) approach (Cutler
1952
),
which is considered to be the earliest modern prediction coding design. Unlike pulse
code modulation (PCM) (Waggener
1995
), DPCM does not code the current signal
directly. Instead, the difference between the current signal and the reconstructed
signal forehead is coded. DPCM utilizes the temporal or spatial correlation of signals
essentially, which is the key point of prediction coding. Soon after the DPCM comes
out, it was introduced into video coding by Oliver (
1952
) and Harrison also in 1952
(Harrison
1952
).
With the development of prediction coding used in video coding, many prediction
coding methods have been proposed. According to whether the prediction samples
are from the current picture or not, prediction techniques can be classified into two
categories in general, intraprediction and interprediction.
Intraprediction is proposed by Harrison (
1952
) first. He treated the linear com-
bination of reconstructed values of several previous coded pixels as the prediction
value of the current pixel in the same picture. Harrison's basic idea is exactly based on
DPCM. He introduced DPCM into intra-picture coding and compared 1-D DPCM,
which utilized neighboring pixels in the same line, and 2-D DPCM, which utilized
