Image Processing Reference
In-Depth Information
Right view for
3D program
H.265/HEVC
Encoder
H.265/HEVC
Decoder
Shared 2D/3D
program
Inter-view Prediction
(Optional)
Left view for
2D program
H.264/AVC
Encoder
H.264/AVC
Decoder
2D
Display
Fig. 3.10 Hybrid architecture based on H.264/AVC
Fig.
3.10
. However, while in the former scheme two codecs are required, one for
each view, in the latter a new standardization is needed.
3.3.2 Multiview Video Coding
Multiview video coding (MVC) was developed as an extension of the monoview
(or monoscopic) H.264/AVC video coding standard. MVC provides a compact
representation for multiple views of a video scene without compromising spatial
resolution or video quality, relatively to frame-compatible formats. To achieve high
compression efficiency, inter-view prediction is also used in addition to existing
spatial and temporal predictions. The basic concept of inter-view prediction, intro-
duced in the multiview profile of the MPEG-2 video coding standard [
25
] and
further developed in H.264/AVC, is to exploit the existing redundancy between
multiple views of a video scene, since in a multiview scenario the various views of
the video scene are typically captured by nearby viewpoints, thus exhibiting
substantial inter-view redundancy [
26
]. With the advent of new extensions of the
HEVC standard, multiview video coding has been further developed in a display
scalable way.
Nevertheless, MVC involves coding multiple views, increasing linearly the
required bitrate with the number of views. This solution is acceptable for stereo
or for a system using a reduced number of views. When a large number of views are
needed, it becomes impracticable. For such requirements, a different approach was
devised based on the synthesis of intermediate views in the decoder, thus transmit-
ting fewer views. As the synthesis requires depth information, a video-plus-depth
format was proposed, as explained in the following section.
3.3.3 Video-Plus-Depth Coding
Transmission of 3D content using multiple views demands large bandwidths even
when considering a small number of views. However, the display equipment, such
