Variable rate video playback with synchronized audio

Abstract

A system varies the apparent display rate of an audiovisual display by modifying an original set of audio data in accordance with a target display rate, then modifying a related original set of video data to conform to the modifications made to the audio data set, such that the modified audio and video data sets are synchronized. The apparent display rate can be faster or slower than a normal display rate for the original sets of audio and video data. Preferably, the method for modifying the original audio data set is one that produces a modified audio data set that can be used to generate an audio display having little or no distortion.

1 . A method of modifying audio/video data, the method comprising:
 determining a target display rate that differs from a normal display rate of an original set of video data and an original set of audio data;   creating a modified set of audio data that corresponds to the original set of audio data,
 wherein the modified set of audio data is created based at least in part on the target display rate; and 
   creating a modified set of video data that corresponds to the original set of video data,
 wherein the modified set of video data is generated based on at least one of the modified set of audio data, a correspondence between the original set of audio data and the modified set of audio data, and a correspondence between the original set of audio data and the original set of video data. 
   
     
     
         2 . The method of  claim 1 , wherein
 the modified set of video data is synchronized to the modified set of audio data at the target display rate.   
     
     
         3 . The method of  claim 1 , wherein
 the original set of video data and the original set of audio data are synchronized at the normal display rate.   
     
     
         4 . The method of  claim 1 , further comprising:
 determining a correspondence between the original set of audio data and the original set of video data by:
 dividing the original set of video data into a plurality of subunits, each representing a substantially equal duration of time; 
 dividing the original set of audio data into a plurality of segments, each segment representing a duration of time that is approximately coincident with and substantially equal to the duration of time of a corresponding subunit of the original set of video data; and 
 identifying corresponding subunits of the original set of video data and segments of the original set of audio data. 
   
     
     
         5 . The method of  claim 1 , wherein creating a modified set of video data comprises:
 identifying one or more partial or complete subunits of the original set of video data that correspond to audio segments of the modified set of audio data, based upon a correspondence between the modified set of audio data and the original set of video data; and   modifying the subunits of the original set of video data to produce the modified set of video data so that there is a one-to-one correspondence between audio segments of the modified set of audio data and subunits of the modified set of video data.   
     
     
         6 . The method of  claim 1 , wherein creating a modified set of video data comprises:
 grouping the modified set of audio data into audio segments, each segment representing a duration of time that is approximately coincident with and substantially equal to the duration of time of a frame of video data;   identifying one or more partial or complete frames of the original set of video data that correspond to each of the audio segments of the modified set of audio data, based upon a correspondence between the modified set of audio data and the original set of video data; and   modifying the frames of the original set of video data to produce the modified set of video data so that there is a one-to-one correspondence between audio segments of the modified set of audio data and frames of the modified set of video data.   
     
     
         7 . The method of  claim 1 , wherein creating a modified set of video data includes eliminating data from the original set of video data. 
     
     
         8 . The method of  claim 1 , wherein creating a modified set of video data includes blending data from the original set of video data so that the modified set of video data has less data than the original set of video data. 
     
     
         9 . The method of  claim 1 , further comprising:
 generating an audio display from the modified set of audio data; and   generating a video display from the modified set of video data.   
     
     
         10 . A tangible computer-readable medium storing instructions for modifying audio/video data, comprising:
 determining a target display rate that differs from a normal display rate of an original set of video data and an original set of audio data; and,   creating a modified set of audio data that corresponds to the original set of audio data,
 wherein the modified set of audio data is created based at least in part on the target display rate. 
   
     
     
         11 . The method of  claim 10 , further comprising:
 creating a modified set of video data that corresponds to the original set of video data,
 wherein the modified set of video data is generated based on at least one of the modified set of audio data, a correspondence between the original set of audio data and the modified set of audio data, and a correspondence between the original set of audio data and the original set of video data. 
   
     
     
         12 . The computer-readable medium of  claim 11 , wherein creating a modified set of video data comprises:
 grouping the modified set of audio data into audio segments;   identifying one or more partial or complete subunits of the original set of video data that correspond to each of the audio segments of the modified set of audio data, based upon a correspondence between the modified set of audio data and the original set of video data; and   modifying the subunits of the original set of video data to produce the modified set of video data so that there is a one-to-one correspondence between audio segments of the modified set of audio data and subunits of the modified set of video data.   
     
     
         13 . The computer-readable medium of  claim 11 , wherein creating a modified set of video data comprises:
 grouping the modified set of audio data into audio segments, each segment representing a duration of time that is approximately coincident with and substantially equal to the duration of time of a subunit of video data;   identifying one or more partial or complete subunits of the original set of video data that correspond to each of the audio segments of the modified set of audio data, based upon a correspondence between the modified set of audio data and the original set of video data; and   modifying the subunits of the original set of video data to produce the modified set of video data so that there is a one-to-one correspondence between audio segments of the modified set of audio data and subunits of the modified set of video data.   
     
     
         14 . The computer-readable medium of  claim 11 , wherein creating a modified set of video data comprises:
 grouping the modified set of audio data into audio segments, each segment representing a duration of time that is approximately coincident with and substantially equal to the duration of time of a frame of video data;   identifying one or more partial or complete frames of the original set of video data that correspond to each of the audio segments of the modified set of audio data, based upon a correspondence between the modified set of audio data and the original set of video data; and   modifying the frames of the original set of video data to produce the modified set of video data so that there is a one-to-one correspondence between audio segments of the modified set of audio data and frames of the modified set of video data.   
     
     
         15 . The computer-readable medium of  claim 11 , wherein creating a modified set of video data includes eliminating data from the original set of video data. 
     
     
         16 . The computer-readable medium of  claim 11 , wherein creating a modified set of video data includes blending data from the original set of video data so that the modified set of video data has less data than the original set of video data. 
     
     
         17 . The computer-readable medium of  claim 11 , the method further comprising:
 generating an audio display from the modified set of audio data; and   generating a video display from the modified set of video data.   
     
     
         18 . An apparatus for modifying audio/video data, the apparatus comprising:
 means for determining a target display rate that differs from a normal display rate of an original set of video data and an original set of audio data;   means for creating a modified set of audio data that corresponds to the original set of audio data,
 wherein the modified set of audio data is created based at least in part on the target display rate; and 
   means for creating a modified set of video data that corresponds to the original set of video data,
 wherein the modified set of video data is generated based on at least one of the modified set of audio data, a correspondence between the original set of audio data and the modified set of audio data, and a correspondence between the original set of audio data and the original set of video data. 
   
     
     
         19 . The apparatus of  claim 18 , wherein
 the modified set of video data is synchronized to the modified set of audio data at the target display rate.   
     
     
         20 . The apparatus of  claim 18 , wherein
 the original set of video data and the original set of audio data are synchronized at the normal display rate.