Browse Prior Art Database

Fast Video Start-Up in Video Conference Systems

IP.com Disclosure Number: IPCOM000117348D
Original Publication Date: 1996-Feb-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Horiuchi, Y: AUTHOR [+2]

Abstract

Disclosed is a method to improve start-up time of the motion video picture in video conference systems. By applying the following characteristics to the initial picture, the motion video can start up quickly on the remote side: o Lowering the quality of a picture decreases the number of bits in that picture. o Small amount of bits are transmitted quickly.

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Fast Video Start-Up in Video Conference Systems

      Disclosed is a method to improve start-up time of the motion
video picture in video conference systems.  By applying the following
characteristics to the initial picture, the motion video can start up
quickly on the remote side:
  o  Lowering the quality of a picture decreases the number of bits
in
      that picture.
  o  Small amount of bits are transmitted quickly.

      In video conference systems, huge video data is encoded and
compressed by such encoders as H.261 and Motion Picture Experts Group
(MPEG) before transmission.  These encoders generate I and P pictures
(*1).  Since the initial picture is always I picture, which has three
to four times more bits than P picture, it takes much time until it
is displayed on the remote screen.  In other words, start-up time of
video is slow, and the user is forced to watch a blank screen for
some unacceptable time.

      By degrading the quality of the initial picture, video can
start-up faster than before.  A compromise between quality and speed
may be found by choosing the compression ratio.  High compression
gives low quality and high start-up speed.  Low compression does high
quality and slow start-up.  The compression ratio is chosen by
changing the quantizer scale of the encoder, by inserting or removing
a preprocessing  filter or by combination of these.

      Experiments show that very high compression ratio can be used
to get fas...