Summary: Visual Communications and Image Processing (VCIP), January 2001.
Reliable Video Communication over Lossy Packet Networks
using Multiple State Encoding and Path Diversity
John G. Apostolopoulos
Palo Alto, CA, USA
Video communication over lossy packet networks such as the Internet is hampered by limited bandwidth and packet
loss. This paper presents a system for providing reliable video communication over these networks, where the system
is composed of two subsystems: (1) multiple state video encoder/decoder and (2) a path diversity transmission
system. Multiple state video coding combats the problem of error propagation at the decoder by coding the video
into multiple independently decodable streams, each with its own prediction process and state. If one stream is
lost the other streams can still be decoded to produce usable video, and furthermore, the correctly received streams
provide bidirectional (previous and future) information that enables improved state recoveryfor the corrupted stream.
This video coder is a form of multiple description coding (MDC), and its novelty lies in its use of information from
the multiple streams to perform state recovery at the decoder. The path diversity transmission system explicitly
sends di erent subsets of packets over di erent paths, as opposed to the default scenarios where the packets proceed
along a single path, thereby enabling the end-to-end video application to e ectively see an average path behavior.
We refer to this as path diversity. Generally, seeing this average path behavior provides better performance than