Page 116 - ITU Journal, ICT Discoveries, Volume 3, No. 1, June 2020 Special issue: The future of video and immersive media
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ITU Journal: ICT Discoveries, Vol. 3(1), June 2020
not employ any type of prediction structure, nor uses Table 2 – Bjøntegaard delta rate (BD-BR (%)) and BD-PSNR (dB): Bit-
rate savings and average PSNR difference comparison (reference in
depth maps, which is enough for very high-density light
boldface).
fields. Its design relies on a very simple R-D governed
pipeline. These results have been reported in [17]. PSNR-YUV BD-BR (%)
Greek Sideboard Tarot Set2
The performance of the 4DPM, which relies on the hier-
4DPM vs x265 -33.47 -29.59 22.37 -32.34
archical depth-based view reconstruction scheme, is il-
PSNR-Y BD-BR (%)
lustrated in Fig. 10. The PSNR-YUV results are reported
for the high-density camera-array (HDCA) images Greek, Greek Sideboard Tarot Set2
Sideboard, Tarot, and Set2 [18]. Table 2 shows the Bjøn- 4DPM vs x265 -5.12 -17.06 68.23 -1.28
tegaard delta rate (BD-BR (%)) and the Bjøntegaard delta
PSNR-YUV BD-PSNR (dB)
PSNR (BD-PSNR (dB) [20, 19] regarding the PSNR-Y and
Greek Sideboard Tarot Set2
PSNR-YUV results obtained for the HDCA images. The
HDCA images correspond to light fields with wide base- 4DPM vs x265 0.80 0.91 -0.71 1.41
lines, offering less redundancy between the views, when PSNR-Y BD-PSNR (dB)
compared to the lenslet-based light fields. The 4DPM out- Greek Sideboard Tarot Set2
performs x265 especially at the low rates due to the effi-
4DPM vs x265 0.17 0.46 -1.56 0.32
cient depth-based view reconstruction scheme. The com-
parisons have been conducted according to the Common
Two groups of conformance tests are currently available.
Test Conditions specifications and validated by ISO/IEC
These groups retain a subset of features from JPEG Pleno
SC29 WG1 experts.
Part 2 standard, which depends on the encoding mode.
Table 1 – Bjøntegaard delta rate (BD-BR (%)) and BD-PSNR (dB): Bit- The first group of tests corresponds to the 4DTM tool. The
rate savings and average PSNR difference comparison (reference in second group of tests addresses the 4DPM tool.
boldface).
During the decoder conformance testing, a procedure is
PSNR-YUV BD-BR (%)
executed to evaluate the conformance according to the
Bikes Danger Fountain Pillars
conformance class the decoder belongs to, given a spe-
4DTM vs x265 -32.15 -36.37 -6.22 -30.24 cific encoding mode. conformance classes define the con-
4DPM vs x265 -0.32 -13.65 -5.86 -13.07
straints to which a given JPEG Pleno implementation is
4DTM vs 4DPM -31.47 -21.97 -11.15 -10.51
subjected.
PSNR-Y BD-BR (%)
Bikes Danger Fountain Pillars The procedures are designed based on abstract test suites
4DTM vs x265 -19.02 -24.18 -13.04 -20.23 (ATS) specifications, which define general tests for com-
4DPM vs x265 0.80 -14.87 -8.59 -11.39 ponents of parts 1 and 2 of the JPEG Pleno standard. Each
4DTM vs 4DPM -22.37 -7.06 3.08 -0.83 ATS defines test purposes, methods, and references of the
PSNR-YUV BD-PSNR (dB) portion of the document that is being tested. The practi-
cal embodiment of the ATS are the executable test suites
Bikes Danger Fountain Pillars
(ETS). Commonly ATS are embodied into one ETS, which
4DTM vs x265 1.41 1.46 0.54 0.96
4DPM vs x265 0.31 0.62 0.33 0.43 consists of codestreams, reference decoded images, a tex-
4DTM vs 4DPM 0.95 0.69 0.26 0.31 tual description of the contents of the codestream and tol-
erance values for MSE and peak error.
PSNR-Y BD-PSNR (dB)
Bikes Danger Fountain Pillars
4.4 JPEG Pleno Part 4: Reference software
4DTM vs x265 1.06 1.11 0.11 0.73
4DPM vs x265 0.29 0.77 0.52 0.49 For the purpose of testing JPEG Pleno encoder and de-
4DTM vs 4DPM 0.72 0.24 -0.18 0.07
coder implementation and to help those implementing
adequately understand the algorithms and methods of
Parts 1 and 2, the JPEG Committee provides a reference
4.3 JPEG Pleno Part 3: Conformance testing software in JPEG Pleno Part 4 (ISO/IEC 21794-4). The
source code of this reference software is informative only.
JPEG Committee has established JPEG Pleno Part 3 for
It is entitled Jpeg Pleno Model (JPLM) and has been devel-
describing the conformance testing methodology used to
oped to ensure a fast proliferation of the JPEG Pleno stan-
ensure that an application complies with the standard. It
dard and to be utilized in the conformance testing proce-
provides a framework to enable conformity testing and
dure described in Section 4.3.
includes, for instance, a description of expected function-
ality, quality, and speed performance testing. Since the The JPLM was designed with a focus on maintainabil-
JPEG Pleno standard includes a considerable bulk of fea- ity, integrability, and extensibility rather than encoding
tures, which can be used for enabling diverse applica- and decoding speeds. These non-functional requirements
tions, a series of conformance tests are being defined. were prioritized because the JPEG Pleno is a complex mul-
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