Quality Assessment - 3DTV: Processing and Transmission of 3D Video Signals - page 168

of the wall behind the display is 20 lux. These environmental luminance
measures remained the same for all test sessions, as the lighting conditions
of the test room are kept constant. The original, MPEG-4 SVC coded colour-
plus-depth image sequences are initially combined in side-by-side video
sequences. These side-by-side image sequences are then input to the 3D
display to allow subjects to evaluate the perceptual quality.

6.3.1.4 3D Video Compression

The encoding parameters used are listed in Table 6.2, and the details of the
video sequences considered in this chapter are given in Appendix A.
JSVM version 8.9, developed by the JVT (Joint Video Team), is used
to perform SVC compatible encoding of both colour texture and depth
video sequences. When encoding colour-plus-depth-based 3D videos, the
base layer of the codec is used to encode the colour texture video, and
the enhancement layer is used to encode the corresponding depth map of
the 3D sequence. Performances of the quality assessment methodologies
considered in this chapter are verified for eight video sequences through
subjective testing. The stimulus set for each test differs depending on the
quality variations of colour texture video and depth map, and is described
in the following sections. In each of the subjective evaluation tests, observers
are asked to rate the 3D video for the particular quality attribute(s) under
investigation according to the Double Stimulus Continuous Quality Scale
(DSCQS) method, as described in ITU-Recommendation BT.500-11 [11].
Before each test, a handout is given to the observers explaining about the
assessment, the grading scale, the sequence and timing (reference picture,
grey, test picture and voting period), according to in ITU-Recommendation
BT.500-11. An example handout is shown in Appendix B. Example clips
are shown to familiarize the viewer with the assessment procedure. Any
remaining questions are answered before the start of the test and they are
assisted during the whole test procedure.

Table 6.2 Encoding parameters

Encoding parameter Value

Encoder JSVM (Joint Scalable Video Model)

reference software codec Version 8.9

Number of sequences 8

Sequence length 10s

Sequence format IPPP

Reference frames 1

Entropy coding CABAC (Content Adaptive Binary

Arithmetic Coding)