Page 71 - Video Coding for Mobile Communications Efficiency, Complexity, and Resilience

48 Chapter 3. Video Coding: Standards

content-based interactivity (content-based multimedia data-access tools,
content-based manipulation and bitstream editing, hybrid natural and synthetic
data coding, improved temporal random access), compression (improved cod-
ing e,ciency, coding of multiple concurrent data streams), and universal
access (robustness in error-prone environments, content-based scalability). Ver-
sion 1 of the MPEG-4 standard was approved in October 1998. A second
version was approved in December 1999 to add new functionalities and im-
prove others. The MPEG-4 standard is o,cially known as ISO=IEC 14496
and is titled “Generic coding of audiovisual objects” [67]. This title describes
two important properties of the MPEG-4 standard. The /rst property is that
it is a generic standard. It is designed to cover a wide range of bit rates
(typically, 5 kbits=s to 10 Mbits=s), picture formats (progressive and inter-
laced), resolutions (SQCIF to beyond TV), frame rates (still images to high
frame rates), communication networks (wired or wireless), input material (nat-
ural or synthesized), etc. The second property is that it uses an object-based
representation model, where a scene is represented, coded, and manipulated
as individual audiovisual objects. This particular property (i.e., being object-
based) sets MPEG-4 apart from earlier block-based standards. Thus, in addi-
tion to conventional block-based MC-DPCM=DCT techniques, MPEG-4 adopts
more recent object-based techniques like second-generation coding techniques
(Section 2.6.5) and model-based coding techniques (Section 2.7.3). MPEG-4
is described in more detail in Section 3.5.

3.3.10H.263++

Technically, H.263++ is version 3 of the H.263 standard [68]. This version
was developed by ITU-T=SG16=Q15, with technical content completed and
approved late in the year 2000. The H.263++ standard added some more
features to H.263 and H.263+. These new features improve coding e,ciency,
enhance error resilience, provide additional supplemental display and external
usage capabilities, and de/ne pro/les and levels. H.263++ is described in
more detail in Section 3.4.

3.3.11 H.26L
This is a project of ITU-T=SG16=Q15. The H.26L project is planned to be a
new-generation video coding standard with improved e,ciency, error
resilience, and streaming support. It is scheduled for completion in 2002.
In addition to the standard documents themselves, interested readers are
referred to some excellent reviews and tutorials available in the literature
[69, 70, 65, 71–75, 11, 13, 15].