Page 178 - Video Coding for Mobile Communications Efficiency, Complexity, and Resilience

Section 6.4. Discussion 155

can, at very low bit rates, drop below that of single-reference codecs. Com-
bined with rate constraints, the LTM-MCP technique provides a superior R-D
performance, which becomes more evident as the bit rate increases.
The chapter investigated the properties of long-term memory block-motion
)elds. It was found that the distribution of the long-term memory spatial dis-
placements is center-biased. This distribution becomes more spread with in-
creased frame memory size and frame skip. It was also found that the distri-
bution of the long-term memory temporal displacement is zero-biased. Again,
this distribution becomes more spread with increased frame memory size and
frame skip. The investigation revealed also that the long-term memory block-
motion )eld is highly correlated. In general, it was concluded that moving from
a single-reference system to a multiple-reference system does not signi)cantly
change the properties of the block-motion )eld.