System and method for the broadcast dissemination of time-ordered data

Abstract

A stream of time-ordered data, such as a movie, is divided into multiple fragments of equal length, which are repetitively transmitted at different respective repetition rates. The fragments are reordered for transmission so that those which occur near the beginning of the original data stream are transmitted more frequently than those which occur later in the data stream. When a user enters a request to utilize the data, the individual fragments are stored upon receipt at the user's premises, and reassembled into a contiguous stream. The ordering of the fragments is such that the wait time required before utilization of the data can begin is limited to a predetermined maximum, and at least one copy of every fragment becomes available by the time it is needed.

I/We claim: 
     
         1 . In a media broadcast system in which digital media is divided into a sequence of fragments and the fragments are repetitively transmitted with different repetition periods, a method for presenting the media, the method comprising:
 loading an index of all of the fragments in the sequence;   detecting each individual fragment that is received;   checking the index upon detection of each received fragment to determine whether a copy of the received fragment has been stored;   storing the received fragment if the index indicates that the received fragment has not been previously stored, and setting the index to indicate that the received fragment has been stored; and   commencing to provide the stored fragments to a display device in sequential order within a maximum period of time τ from an indication to begin presenting the media.   
     
     
         2 . The method of  claim 1  wherein storing the received fragment includes storing the received fragment in a buffer. 
     
     
         3 . The method of  claim 1  wherein commencing to provide the stored fragments includes retrieving the fragments from the buffer with a read circuit. 
     
     
         4 . The method of  claim 1  wherein detecting each individual fragment that is received includes determining whether a program identification indicates that the received fragment belongs to the media. 
     
     
         5 . The method of  claim 1  wherein storing the received fragment includes storing the received fragment in a main buffer or forwarding the received fragment to a read circuit for storage in a pre-buffer. 
     
     
         6 . The method of  claim 1 , further comprising storing all of the fragments of the media in a buffer. 
     
     
         7 . The method of  claim 1 , further comprising discarding an individual stored fragment after the individual fragment has been viewed. 
     
     
         8 . A computer implemented method for transmitting a digital presentation, the method comprising:
 dividing the digital presentation, via a processor, into a sequence of fragments; and   transmitting the fragments via multiple substreams, wherein the multiple substreams include an encoded substream and a conventional substream, and wherein—
 the encoded substream includes only a portion of the fragments from a first temporal portion of the presentation, 
 the conventional substream includes all of the fragments of the digital presentation, and 
 the transmission of the encoded substream is time shifted such that the encoded substream and the conventional substream transmit all of the fragments of the first temporal portion of the digital presentation within a time period,
 wherein the time period is no greater than the length of the first temporal portion. 
 
   
     
     
         9 . The method of  claim 8  wherein the conventional substream is time-division multiplexed. 
     
     
         10 . The method of  claim 8  wherein the digital presentation has a temporal length T, and wherein the encoded substream and the conventional substream are transmitted at a periodicity of T. 
     
     
         11 . The method of  claim 8  wherein—
 the encoded substream is a first encoded substream, 
 the multiple substreams includes multiple additional encoded substreams, 
 the digital presentation includes multiple additional temporal portions, 
 individual encoded substreams include only a portion of corresponding fragments from corresponding temporal portions, and 
 the transmission of individual encoded substreams is time shifted such that the encoded substreams and the conventional substream transmit all of the fragments of individual temporal portions of the digital presentation within a time period that is no greater than the length of the individual temporal portions. 
 
     
     
         12 . The method of  claim 8  wherein the multiple substreams are transmitted at a fixed data rate. 
     
     
         13 . The method of  claim 8 , further comprising dividing, via the processor, the fragments into a plurality of segments, and wherein individual segments have a length which is a function of the individual segment's location within the digital presentation. 
     
     
         14 . A computer implemented method for transmitting a digital presentation, the method comprising:
 dividing the digital presentation, via a processor, into a sequence of fragments; and   transmitting the fragments via multiple substreams, wherein the multiple substreams include an encoded substream and a proxy substream, and wherein—
 the encoded substream includes a first subset of fragments from a first temporal portion of the presentation, 
 the proxy substream includes a second subset of fragments from the first temporal portion of the presentation, 
 the first subset and the second subset together include all of the fragments of the first temporal portion, and 
 the encoded substream and the proxy substream are transmitted at a periodicity that provides all of the fragments of the first temporal portion within a time period
 wherein the time period is no greater than the length of the first temporal portion. 
 
   
     
     
         15 . The method of  claim 14  wherein the digital presentation has a temporal length T, and wherein the encoded substream and the proxy substream are transmitted at a periodicity less than T. 
     
     
         16 . The method of  claim 14  wherein the digital presentation has a temporal length T, and wherein the encoded substream and the proxy substream are transmitted at a periodicity less than T/2. 
     
     
         17 . The method of  claim 14 , further comprising dividing, via the processor, the fragments into a plurality of segments, and wherein the encoded substream includes a single segment. 
     
     
         18 . The method of  claim 14  wherein—
 the encoded substream is a first encoded substream, 
 the multiple substreams includes a second encoded substream having a third subset of fragments from a second temporal portion of the presentation, 
 the proxy substream includes a fourth subset of fragments from second temporal portion of the presentation, 
 the third subset of fragments and the fourth subset of fragments together include all of the fragments of the second temporal portion, and 
 the lengths of the first temporal portion and the second temporal portion are a function of their individual locations within the digital presentation. 
 
     
     
         19 . The method of  claim 14  wherein—
 the proxy substream is a first proxy substream, 
 the encoded substream is a first encoded substream, 
 the multiple substreams includes:
 a second encoded substream having a third subset of fragments from a second temporal portion of the presentation, and 
 a second proxy substream having a fourth subset of fragments from the second temporal portion of the presentation, and 
 
 the third subset of fragments and the fourth subset of fragments together include all of the fragments of the second temporal portion. 
 
     
     
         20 . The method of  claim 19  wherein the first proxy substream and the second proxy substream have data rates that are less than the data rates of the first encoded substream and the second encoded substream.