Video packet multiplexer with intelligent packet discard

Abstract

A IP video delivery system (10) includes a multiplexer (30) for transmitting multiple data streams of packets over link (31) to a site having one or more receivers (22). During times of congestion, the multiplexer will discard packets from its internal queues. Packets are intelligently chosen to minimize the effects on the output from the receivers (22) by taking into account timing information related to the packets and priority.

Description

STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0001] The U.S. Government has a paid-up license in this invention and the right in limited circumstances to require the patent owner to license others on reasonable terms as provided for by the terms of Award No. 70NANB3H3053 awarded by National Institute of Standards and Technology.BACKGROUND OF THE INVENTION [0002] 1. Technical Field [0003] This invention relates in general to network communications and, more particularly, to a method and apparatus for discarding packets. [0004] 2. Description of the Related Art [0005] In a digital information delivery network, between a source device and a destination device, packets of data may be lost for a variety of reasons. Some packets are randomly lost due to uncontrollable errors - for example, errors caused by noise on a transmission line, synchronization-issues, etc.-Some-packets are lost due to congestion, i.e., it is not possible for a network element to transmit all received p...

AI Technical Summary

Benefits of technology

[0010] The present invention provides significant advantages over the prior art. By selectively discarding packets from the queue, the degradation of the resulting video during times of congestion is greatly improved.

Problems solved by technology

In a digital information delivery network, between a source device and a destination device, packets of data may be lost for a variety of reasons.

Some packets are randomly lost due to uncontrollable errors - for example, errors caused by noise on a transmission line, synchronization-issues, etc.-Some-packets are lost due to congestion, i.e., it is not possible for a network element to transmit all received packets in a timely manner.

For some data transfer protocols, missing packets cause the destination device to request a retransmission of the missing information.

This is not very feasible, however, in a network that has multicasting of real-time streams such as audio or video.

Normally, there will not be enough time available for requesting and receiving the retransmitted packets, unless buffers at the destination device are very large.

Error concealment techniques will in most cases result in degradation of output quality and are incapable of correcting some errors; further, the degree of the output error will be different depending upon the type of data in the lost packet, some of which will be more difficult to conceal than others.

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