Scalable and Ultra-High Resolution MPEG Video Delivery on Tiled Displays (Thesis)
Video is a powerful means for people to communicate with each other
across space and time. Its effectiveness is largely dependent on
resolution and scale. Unlike most other information technologies,
video resolution was increasing slowly during the past two decades.
One of the major limiting factors was display resolution, which has
been improving only at a rate of about 5% per year, while processor
performance, memory density, network bandwidth and disk storage
capacity are doubling every 18 to 24 months as predicted by Moore's
Law. To overcome the resolution limit, researchers have recently
proposed ways to construct multi-projector tiled display systems
driven by commodity PC clusters. However, ultra-high resolution
videos have not been available on such displays for several reasons.
First, video resolution has been limited to the HDTV standard.
Second, it has been difficult to parallelize MPEG video decoders to
run on a cluster due to limited communication performance in the
typical architecture. Third, to appear seamless, ultra-high resolution
videos require accurate projector calibration, which is difficult to
achieve on large-scale tiled displays.
This dissertation presents a framework for decoding and displaying
ultra-high resolution videos on a scalable multi-projector tiled
display system driven by a PC cluster. It proposes a classification
of three kinds of scalable resolution videos for tiled displays.
First, a single ultra-high resolution video can be used for
applications such as digital cinema or planetarium. Second, in remote
scientific visualization, multiple low-resolution videos can be tiled
to create scalable video resolution. Third, for immersive
tele-presence applications, a high-resolution video can be formed by
overlaying multiple low-resolution videos with different fields of
Towards realizing this framework, this dissertation presents the
design, implementation and evaluation of several key components
necessary for building a scalable MPEG decoding system for tiled
displays. The first component, a high-performance software MPEG video
decoder, is used as the underlying building block for the scalable
decoding system. Secondly, we propose a hierarchical parallel
algorithm to decode and display ultra-high resolution MPEG streams on
a PC cluster. Finally, sub-pixel accurate projector alignment is
achieved with the camera homography tree algorithm; improved color
consistency is attained using a new full-gamut color matching system.
With these implementations, the system is able to accomplish a
demanding task---it plays an IMAX quality, 3840 by 2800 pixel video at
about 39 frames per second on a tiled display driven by a cluster
of 21 PCs.