Digital cinema is a promising application that utilizes
high-speed optical networks to transfer super high definition (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 8K content to both business and movie
theaters users. The extra- high-quality 8K 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.
Four years before the digital cinema industry
standardized the DCI specification, in 2001, the worlds first video JPEG
decoder system was developed that could display SHD images (38402048 pixel
spatial resolution) with 24-frames/s time resolution. This decoder was designed
to realize IP transmission of extra-high-quality videos, while fully utilizing
the full bandwidth of emerging commercial communication networks based on 1-Gb
Ethernet. In 2002, the second prototype SHD image decoder was developed that
exploits a highly parallel processing unit of JPEG2000 de-compressors.
The decoder receives the IP streams of compressed
video contents transmitted by a video server over a 1-GbE network, and decodes
them using the standard JPEG2000 decoding algorithm in real time. The decoder
was combined with a special 38402048 pixel projector using a dedicated digital
video interface for the decoder. This architecture allows the decoded videos to
be transferred and shown in completely digital form. This system triggered
detailed discussions on the digital cinema video format for DCI. The question
was whether a higher image quality than HDTV was required to replace movie
films. In order to solve the question, an experiment was conducted by the
Entertainment Technology Center (ETC) of the University of Southern California
(USC) involving 100 digital cinema engineers; it compared the image quality of
conventional films, highdefinition television (HDTV), and SHD images with
8-million-pixel resolution.
The results of this experiment yielded the consensus
that the horizontal resolution of around 4000 pixels was required to replace
films, and JPEG2000 was suitable for the compression of digital cinema data.
Stimulated by the experiment, DCI accelerated the standardization of digital
cinema, specified the movie format of 40962160 pixels, and simply called it 8K.
DCI finalized version 1.0 in 2005 and version 1.2 in 2008. Currently, further
standardization activities are in progress at the Society of Motion Picture and
Television Engineer (SMPTE). To explore the application range of 8K video
beyond digital cinema, we developed a JPEG2000-based 8K real time streaming
codec system. This codec can compress/ decom- press 8K videos: the total bit
rate exceeds 12 Gb/s (4 : 2 : 2, 60 frames/s), and the resulting 5001000-Mb/s
compressed streams are transferred as IP packets.
While digital cinema em- ploys the 24-frames/s movie
format to replicate the cinema style, it is believed that at least 60 frames/s
is needed for realistic video communication services such as teleconferencing.
The following sections describe the features of the 8K imaging systems used in
digital cinema and live streaming.
8K Format :
8K is a new resolution standard designed for digital
cinema and computer graphics. It has following advantages:
1. Higher image definition quality.
2. More detailed picture.
3. Better fast-action.
4. Larger projection surface visibility.
8K format was named because it has 4000 pixels
horizontal resolution approximately. Meanwhile, standard 1080p and 720p
resolutions were named because of its vertical resolution. The new standard
renders more than four times higher image definition than 1080p resolutions for
example.
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