Scalable and ultra-high resolution mpeg video delivery on tiled displays

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 view. 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.