Browse Prior Art Database

Adaptive Video Bandwidth Controller

IP.com Disclosure Number: IPCOM000117126D
Original Publication Date: 1995-Dec-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 4 page(s) / 110K

Publishing Venue

IBM

Related People

Kandlur, DD: AUTHOR [+3]

Abstract

Disclosed is a method for dynamic control over the capture and transmission of multimedia data in a Multimedia Multiparty Teleconferencing session, with a graceful degradation in the information quality.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Adaptive Video Bandwidth Controller

      Disclosed is a method for dynamic control over the capture and
transmission of multimedia data in a Multimedia Multiparty
Teleconferencing session, with a graceful degradation in the
information quality.

      In a Multimedia Multiparty Teleconference (MMT) session each
participating station transmits video, audio, and data streams to the
other members of the conference (Fig. 1).  As the number of
participants increases, the bandwidth requirements and processing
overhead for each end-station may become very large.  Moreover, in
shared network environments such as Ethernet and Token Ring, the
available bandwidth is limited, and few, if any, mechanisms are
available to manage the available bandwidth and control access to the
network.  As a consequence, network congestion may occur, and
deteriorate the performance of all users in a manner that is
unpredictable and unmanageable from the end-user perspective.  In
some cases, such as the Ethernet environment, increased congestion,
leads to a higher number of collisions, and can in fact, decrease the
available bandwidth.  In order to maintain full connectivity between
all users, a method of reducing the aggregate bandwidth requirements,
while minimizing the reduction in useful information exchange, is
needed.

      An MMT session is defined as a multiway communication using
video, audio and data simultaneously between multiple end-stations.
Typically, in an MMT session, the most bandwidth consuming component
is the video so control over this component is critical.

      The basic concept behind the dynamic bandwidth controller is
that an end-station controls the capture and compression of the
video, possibly in response to network "backpressure" created by
contention/congestion, to adapt its transmission rate.  This careful
reduction in transmission results in a degradation in quality, but
does so more gracefully than when packets are discarded by the
network.

      The environment for the bandwidth control mechanism is shown
in Fig. 2.  Bandwidth control is achieved with the cooperation of the
video capture, video compression, and network transport systems, in
response to an external signal.  Upon receiving this signal, the
video capture system suspends capture of input frames on a frame
boundary.  The video compression system t...