IEEE Consumer Electronics Magazine - October 2015 - 80

0.9

520

0.8

BT.709
DCI P3
BT.2020

540

0.7
560
0.6
500
0.5
y

580

0.4
0.3

600
620
D65

490

700

0.2
0.1

480

0.0
0.0

470
460
0.1

380
0.2 0.3

0.4
x

0.5

0.6

0.7

0.8

FIGURE 14. The CIE 1931 xy chromaticity diagram with the BT.709
[21], DCI P3 [22], and BT.2020 [23] color gamut.

not visible by the human eye). The generated content is
directly compressed using a single high-bit-depth codec. At
the decoder side, the HDR content is reconstructed using the
inverse of the perceptual curve. These techniques need only
one codec and require a bit depth of 10 to 14 b for a high-quality HDR content reconstruction. As the perceptual encodings

are designed for HDR, they can encode most of what the
human eye can see (not gamut limited). This scenario corresponds to the pipeline shown in Figure 16(a).
The final group of HDR video coding techniques involves
the derivation of metadata to reconstruct HDR content from
LDR or vice versa [30]. Only one stream (original HDR or its
tone-mapped LDR version) is then compressed and transmitted with the metadata embedded in the bitstream. In the case
of transmitting HDR content, it is first perceptually encoded
and then compressed using a video codec. This group of
HDR compression techniques relies greatly on the tradeoff
between the amount of metadata to be sent and the quality of
the reconstructed LDR/HDR content. Both scenarios (LDR
and HDR compression) correspond to the pipelines illustrated in Figure 17.
All three categories of HDR video coding approaches rely
on using video codecs. The most recent video compression
standard is the ITU-T H.265/MPEG-H Part 2 "High Efficiency Video Codec" (HEVC) [31], which delivers the same visual quality as its successor the ITU-T H.264/MPEG-4 Part 10
"Advanced Video Coding" (AVC) codec [32] at only half of
the bit rate. HEVC was developed by the Joint Collaborative
Team on Video Coding and released in January 2013. Both
HEVC and AVC support 10-b integer content and, thus, can
be used for compressing HDR video content that is converted
to integer values. An extension for HEVC is currently being
issued to support high bit depth, gamut scalability, etc. This
extension is called HEVC Range Extensions (RExt). In 2013,
an ad-hoc group was initiated by the MPEG committee to
evaluate possible extensions of HEVC for HDR and wide
color gamut (WCG) video coding applications [33]. Many

Display

Video Content
HDR Content
SMPE ST 2084 (PQ)
10/12 B Depth (30/36 bpp)
Full Visible Gamut
0.005-10,000 cd/m2

HDR
Prototype TV

Distribution

UHDTV Content
BT.1361 (Gamma)
10/12 B Depth (30/36 bpp)
BT.2020
0.01-500 cd/m2

* TV Broadcast
* Blu-ray
* DVD
* Video on Demand

HDTV Content
BT.1361 (Gamma)
8 B Depth (24 bpp)
BT.709
0.1-100 cd/m2

UHD TV
BT 709/ DCI P3/BT 2020
0.01-500 cd/m2

HD TV
BT.709
0.1-100 cd/m2

*Luminance ranges of displays are just informative.
**bpp corresponds to bit per pixel.

FIGURE 15. The distribution pipeline for HD, UHD, and HDR content.
80 IEEE Consumer Electronics Magazine

BT 709/ DCI P3/BT 2020/
Full Visible Gamut
0.005-10,000 cd/m2

october 2015

Table of Contents for the Digital Edition of IEEE Consumer Electronics Magazine - October 2015