Object-based audio-visual terminal and bitstream structure

Abstract

As information to be processed at an object-based video or audio-visual (AV) terminal, an object-oriented bitstream includes objects, composition information, and scene demarcation information. Such bitstream structure allows on-line editing, e.g. cut and paste, insertion/deletion, grouping, and special effects. In the interest of ease of editing, AV objects and their composition information are transmitted or accessed on separate logical channels (LCs). Objects which have a lifetime in the decoder beyond their initial presentation time are cached for reuse until a selected expiration time.

We claim: 
     
         1 . A method for processing object-based video data at a terminal comprising:
 (a) receiving a bit stream comprising at least one object and composition information for the object; wherein the composition information comprises composition parameters and time information for processing the object;   (b) accepting an external input to the terminal;   
       (c) processing the composition information and the external input to compose a video corresponding to the object and the external input; and 
       (d) outputting the composed video. 
     
     
         2 . The method according to  claim 1 , wherein the object comprises an object having immediate visual relevancy. 
     
     
         3 . The method according to  claim 1 , wherein the accepting comprises storing external input to an input buffer. 
     
     
         4 . The method according to  claim 1 , wherein the processing comprises combing user interaction with the composition information. 
     
     
         5 . The method according to  claim 1 , wherein the composition parameters comprise one or more of displacement, rotation angle, and zooming factor of the video object. 
     
     
         6 . The method according to  claim 1 , wherein the time information comprises time base and clock reference of the object. 
     
     
         7 . An apparatus for processing object-based video data, comprising:
 (a) a receiver configured to receive a bit stream comprising at least one object and composition information for the object; wherein the composition information comprises composition parameters and time information for processing the object;   (b) a buffer configured to accept an external input;   
       (c) a composer, coupled to the receiver and the buffer, and configured to process the composition information and the external input to compose a video corresponding to the object and the external input; and 
       (d) an output, coupled to the composer, for outputting the composed video. 
     
     
         8 . The system of  claim 7 , wherein the buffer is configured to receive user input. 
     
     
         9 . The system of  claim 8 , further comprising a storage unit configured to store the object.