Method and apparatus for processing variable bit rate information in an information distribution system
AssigneeDIVA Systems Corporation
InventorsClement G. Taylor, Jesse S. Lerman
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Abstract
A method and apparatus for managing both link and disk bandwidth utilization within the context of a multiple subscriber or user information distribution system by selectively providing variable bitrate and constant low bitrate information streams to one or more subscribers.
Claims22
In an information distribution system comprising an information server providing information to a communications link, a method for managing link bandwidth comprising the steps of:
- determining a link bandwidth utilization level;
- providing, via said communications link and in response to said link bandwidth utilization indicating that an overutilization condition does not exist, a first variable bitrate information stream to at least one of said plurality of subscribers, said first variable bitrate information stream having associated with it a bitrate that may vary between a nominal first lower bitrate and a nominal first upper bitrate;
- and
- providing, via said communications link and in response to said link bandwidth utilization indicating that an overutilization condition does exist, a second variable bitrate information stream to said at least one of said plurality of subscribers, said second variable bitrate information stream having associated with it a bitrate that may vary between a nominal second lower bitrate and a nominal second upper bitrate, said nominal second lower bitrate being less than said nominal first upper bitrate and said nominal second upper bitrate being less than said nominal first upper bitrate.
In an information distribution system, apparatus comprising:
- a storage unit, for storing a plurality of programs, each of said programs being represented by a variable bit rate (VBR) encoded stream and a corresponding substantially constant low bit rate (CLBR) encoded stream;
- a server, for retrieving at least one of said programs from said storage unit to form a multiplexed information stream;
- and
- a communications link having a finite bandwidth, for transporting said multiplexed information stream;
- wherein
- said server preferentially multiplexing, for each retrieved program, said VBR encoded stream representing said retrieved program;
- said server, in response to a condition of insufficient communication link bandwidth, multiplexing, for at least one retrieved program, at least a portion of said CLBR encoded stream representing said at least one retrieved program;
- wherein said VBR encoded stream and said CLRB encoded stream comprise, respectively, a quality constrained encoded stream representing said program and a bitrate constrained encoded stream representing said program.
In an information distribution system comprising a storage unit, for storing a plurality of programs, each of said programs being represented by a variable bit rate (VBR) encoded stream and a corresponding substantially constant low bit rate (CLBR) encoded stream, said VBR and CLBR streams being divided into respective pluralities of time extents, a server, for retrieving at least one of said programs from said storage to form a multiplexed information stream, and a communications link having a finite bandwidth, for transporting said multiplexed information stream, a method for managing bandwidth comprising the steps of:
- preferentially multiplexing, for each retrieved program, said VBR encoded time extents representing said retrieved program;
- and
- multiplexing for at least one retrieved program, in response to a condition of insufficient communication link bandwidth, at least a portion of said CLBR encoded time extents representing said at least one retrieved program;
- wherein said condition of insufficient communication link bandwidth is determined by calculating a bandwidth requirement of a plurality of information stream time extents to be multiplexed.
Dependencies are inferred from the claim text.