14-02-2013, 04:45 PM
Digital Cinema and Super-High-Definition Content Distribution on Optical High-Speed Networks
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ABSTRACT
Digital cinema is a promising application that
utilizes high-speed optical networks to transfer super-highdefinition
(SHD) images. The networks are primarily used for
distributing digital cinema contents in packet data form, and
are also used to support new services such as the live streaming
of musicals and sport games to movie theaters. While
current transfer services offer high-definition (HD) quality
video, live-streaming applications will soon shift to providing
cinema quality 4K content to both business and movie theaters
users. The extra-high-quality 4K format enables a realistic
telepresence, and will be combined with special tools such as
video editing systems to realize effective remote collaboration
for business workspaces. This paper introduces successive research
on SHD image transmission and its application, especially
in digital cinema and associated application fields.
INTRODUCTION
The deployment of digital cinema stimulates many advanced
applications that will use super-high-definition
(SHD) imaging systems and high-speed optical fiber
networks. Theater systems for digital cinema, projectors,
and playback video servers have been commercialized
based on the standards issued by the Digital Cinema Initiative
(DCI) [1]. B4K[ is the SHD video format defined in
DCI specification in 2005 [2]. It has a resolution of 4096
2160 pixels, so its image quality is equivalent to that of
35-mm film. The total bit rate of raw 4K videos with the
frame rate of 24 frames/s is about 7 Gb/s. This necessitates
the use of the JPEG2000 algorithm to compress the bit rate
to 250 Mb/s. To deliver the movie data to movie theaters,
hard disk drives and courier services appeared to be the
easiest approach, but a business trial by Nippon Telegraph
and Telephone Corporation Japan (NTT) demonstrated
that network-based delivery was more cost effective and
secure against content piracy. Furthermore, network
transfer also supports a wider variety of contents, namely
public viewing of live-streaming content.
NETWORK DELIVERY OF
DIGITAL CINEMA
From 2005 to 2007, NTT conducted a business trial on 4K
digital cinema distribution and playback [10], [11]. The
purpose of this trial, entitled B4K Pure Cinema,[ was to
verify the feasibility of the DCI specification, and to evaluate
the content delivery scheme using only optical networks,
excluding any physical transport methods such as
hard-disk-based delivery. This is the world’s first regular
exhibition in commercial movie theaters of DCI-compliant
digital cinema. The experiment evaluated video image
quality, viewer impressions, the operation system, data
security, network distribution, theater operating costs, and
other such factors from technical and business viewpoints.
To start the trial, we developed the world first DCI compliant
4K playback server and a distribution network system
while implementing the encrypted secure file transfer
scheme specified by DCI.
Trial of Network Distribution of 4K
Digital Cinema
The trial was supported by cinema industry companies
in the United States and Japan: Warner Brothers Entertainment,
Paramount, Sony Picture Entertainment, Buena
Vista International, Warner Entertainment Japan, and
United International Pictures Far East as content providers;
Toho Cinemas Japan and Warner Mycal Cinemas
Japan joined as theater owners.
The overall configuration of the 4K digital cinema distribution
system that NTT developed for the 4K Pure
Cinema trial is illustrated in Fig. 4. This was the first
network distribution system capable of satisfying the DCI
specifications in Japan. The facilities include two types of
distribution centers, security center and data center, as
well as the distribution center in the United States and six
theaters in Japan, all of which were connected by dedicated
optical fiber networks. The security center generates
the KDMs and sends or forwards the KDMs made by content
providers to the exhibition equipment of various
theaters according to the distribution schedule.
SHD 60P VIDEO STREAMING
CODEC SYSTEM
While conducting the 4K Pure Cinema trial, we have
been exploring further application of 4K image media.
We have developed an SHD video codec system for SHD
video communication. The codec exploits the JPEG2000
algorithm to realize many features such as extra high
quality and low latency for IP transmission that are
realized by an intraframe coding algorithm [13], [14]. In
the case of digital cinema, all movies are compressed and
delivered in advance, and only the decoder is needed to
process data in real time. To realize smooth and mutual
communication via SHD media, a new set of SHD encoder
and decoder was designed to support frame rates of up to
60 frames/s.
NEW APPLICATIONS USING SHD
SHD image media were first defined for digital cinema to
replace 35-mm movie films, and have been deployed in the
entertainment business field. Since various types of SHD I/O
devices such as SHD projectors and live SHD cameras
have been commercialized [22], [23], we could apply SHD
imaging technology to live-streaming applications such as
SHD ODS. Furthermore, we applied SHD image technology
to business fields other than entertainmentoriented
live streaming. The first application is a mutual
TV conference system that uses a multiscreen SHD imaging
system. The second is a video-editing support system
that enables the remote collaboration for video content
creation.
CONCLUSION: SHD AND BEYOND
The development of the SHD imaging system described
herein has accelerated the replacement of film cinema
with digital cinema. Digital cinema will soon utilize movie
content delivery via optical networks. Unlike digital
cinema, which needs only bulk file transfer, ODS utilizes
the networks for real-time data transfer. Both involve oneway
streaming, so transmission latency is not a critical
problem. To implement sophisticated telepresence systems,
however, we need to reduce the transmission latency
while preserving 4K/2K flexibility and stability. Future
studies must enhance the scalability of the SHD codec to
support multiple layers beyond two layers (4K/2K) as well
as achieving lossless compression.