System for random access to content

Abstract

A method for accessing a desired point in time-synchronized data within a stream, the stream being associated with time information, the method including providing a desired presentation time associated with a desired point within a time-synchronized data stream, determining a stream access point, decoding the stream beginning at the stream access point, and assigning a time associated with the stream access point as a utilization time. Related apparatus and methods are also disclosed.

1 - 63 . (canceled) 
     
     
         64 . A method for accessing a desired point in time-synchronized data within a stream, the stream being associated with time information, the method comprising:
 providing a desired presentation time associated with a desired point within a time-synchronized data stream;   determining a stream access point;   decoding the stream beginning at the stream access point; and   assigning a time associated with the stream access point as a utilization time.   
     
     
         65 . The method according to  claim 64  and wherein the time-synchronized data stream comprises a stored time-synchronized data stream. 
     
     
         66 . The method according to  claim 65  and also comprising, after the decoding:
 continuing to decode the stream until a time at which presentation time information associated with the stream corresponds to a presentation time greater than or equal to the desired presentation time,   wherein the time associated with the stream access point comprises the time at which presentation time information associated with the stream corresponds to a presentation time greater than or equal to the desired presentation time.   
     
     
         67 . The method according to  claim 66  and wherein the desired point comprises a desired frame. 
     
     
         68 . The method according to  claim 67  and also comprising:
 utilizing the stream beginning at the utilization time.   
     
     
         69 . The method according to  claim 68  and wherein the utilizing comprises making the stream sensible to at least one human sense. 
     
     
         70 . The method according to  claim 68  and wherein the utilizing comprises displaying the stream. 
     
     
         71 . The method according to  claim 68  and wherein the utilizing comprises utilizing the stream other than by making the stream sensible to at least one human sense. 
     
     
         72 . The method according to  claim 68  and wherein the utilizing comprises performing a splicing process. 
     
     
         73 . The method according to  claim 68  and wherein the utilizing comprises performing a storing process. 
     
     
         74 . The method according to  claim 64  and wherein the determining a stream access point comprises:
 determining a lower bound after which the desired point is likely to be found; and   assigning the stream access point to be a first point at or after the lower bound at which decoding of the stream is available.   
     
     
         75 . The method according to  claim 64  and wherein the determining a stream access point comprises:
 determining a lower bound after which the desired point is likely to be found; and   assigning the stream access point to be a point nearest the lower bound at which decoding of the stream is available.   
     
     
         76 . The method according to  claim 74  and wherein said point at which decoding of the stream is available comprises a point at which efficient decoding of the stream is available 
     
     
         77 . The method according to  claim 75  and wherein said point at which decoding of the stream is available comprises a point at which efficient decoding of the stream is available 
     
     
         78 . The method according to  claim 76  and wherein the point at which efficient decoding of the stream is available comprises a key frame. 
     
     
         79 . The method according to  claim 78  and wherein the stream comprises an MPEG-2 stream and the key frame comprises an I-frame. 
     
     
         80 . The method according to  claim 74  and wherein the lower bound is determined, at least in part, according to a presentation time of a desired frame. 
     
     
         81 . The method according to  claim 75  and wherein the lower bound is determined, at least in part, according to a presentation time of a desired frame. 
     
     
         82 . The method according to  claim 80  and wherein the stream comprises an MPEG-2 stream and the lower bound is within 1 second plus GOP duration of the MPEG-2 PTS value of the desired frame. 
     
     
         83 . The method according to  claim 74  and wherein the lower bound is between approximately 0.7 and approximately 1.2 seconds before the desired presentation time. 
     
     
         84 . The method according to  claim 75  and wherein the lower bound is between approximately 0.7 and approximately 1.2 seconds before the desired presentation time. 
     
     
         85 . The method according to  claim 83  and wherein the desired presentation time comprises a normal play time indication. 
     
     
         86 . The method according to  claim 85  and wherein the determining a stream access point comprises mapping the normal play time indication to a corresponding presentation time stamp. 
     
     
         87 . The method according to  claim 86  and wherein the utilization time comprises a presentation time stamp. 
     
     
         88 . The method according to  claim 87  and wherein the stream comprises an MPEG-2 stream and the presentation time stamp comprises MPEG-2 PTS. 
     
     
         89 . The method according to  claim 85  and wherein the determining a stream access point comprises utilizing an access point index. 
     
     
         90 . The method according to  claim 89  and wherein the access point index comprises a heuristic index. 
     
     
         91 . The method according to  claim 89  and wherein the access point index comprises a RASP index. 
     
     
         92 . The method according to  claim 91  and wherein the stream comprises an MPEG-2 stream. 
     
     
         93 . The method according to  claim 92  and wherein the stream comprises an encrypted stream, and the method also comprises:
 decrypting the encrypted stream.   
     
     
         94 . The method according to  claim 93  and wherein the time-synchronized data comprises audio and/or video data. 
     
     
         95 . The method according to  claim 94  and wherein the time-synchronized data comprises interactive television data. 
     
     
         96 . A data stream accessor for accessing a desired point in time-synchronized data within a stream, the stream being associated with time information, the data stream accessor comprising:
 a stream access point determiner receiving a desired presentation time associated with a desired point within a time-synchronized data stream and determining a stream access point;   a stream decoder decoding the stream beginning at the stream access point; and   a time assignor assigning a time associated with the stream access point as a utilization time.   
     
     
         97 . A data stream accessor for accessing a desired point in time-synchronized data within a stream, the stream being associated with time information, the data stream accessor comprising:
 means for providing a desired presentation time associated with a desired point within a time-synchronized data stream;   means for determining a stream access point;   means for decoding the stream beginning at the stream access point; and   means for assigning a time associated with the stream access point as a utilization time.