Information Technology Reference
In-Depth Information
Chapter 19
Video Streaming with Interactive Pan/Tilt/Zoom
Aditya Mavlankar and Bernd Girod
Abstract.
High-spatial-resolution videos offer the possibility of viewing an
arbitrary region-of-interest (RoI) interactively. The user can pan/tilt/zoom while
watching the video. This chapter presents spatial-random-access-enabled video
compression that encodes the content such that arbitrary RoIs corresponding to dif-
ferent zoom factors can be extracted from the compressed bit-stream. The chapter
also covers RoI trajectory prediction, which allows pre-fetching relevant content in a
streaming scenario. The more accurate the prediction the lower is the percentage of
missing pixels. RoI prediction techniques can perform better by adapting according
to the video content in addition to simply extrapolating previous moves of the input
device. Finally, the chapter presents a streaming system that employs application-
layer peer-to-peer (P2P) multicast while still allowing the users to freely choose
individual RoIs. The P2P overlay adapts on-the-fly for exploiting the commonali-
ties in the peers' RoIs. This enables peers to relay data to each other in real-time,
thus drastically reducing the bandwidth required from dedicated servers.
1
Introduction
High-spatial-resolution digital video will be widely available at low cost in the near
future. This development is driven by increasing spatial resolution offered by digi-
tal imaging sensors and increasing capacities of storage devices. Furthermore, there
exist algorithms for stitching a comprehensive high-resolution view from multiple
cameras [1, 2]. Some currently available video-conferencing systems stitch a large
panoramic view in real-time [3]. Also, image acquisition on spherical, cylindrical
or hyperbolic image planes via multiple cameras can record scenes with a wide
