Picture level adaptive frame/field coding for digital video content

Abstract

A method and system of encoding and decoding digital video content. The digital video content comprises a stream of pictures which can each be intra, predicted, or bi-predicted pictures. Each of the pictures comprises macroblocks that can be further divided into smaller blocks. The method entails encoding and decoding each picture in said stream of pictures in either frame mode or in field mode.

What is claimed is:  
     
         1 . A method of encoding or decoding digital video content, said digital video content comprising a stream of pictures which can each be intra, predicted, or bi-predicted pictures, each of said pictures comprising macroblocks that can be divided into smaller blocks, said method comprising encoding each picture in said stream of pictures in either frame mode or in field mode.  
     
     
         2 . The method of  claim 1 , further comprising encoding or decoding said bi-predicted pictures in said stream of pictures in direct mode.  
     
     
         3 . The method of  claim 2 , further comprising deriving a forward motion vector and a backward motion vector for each of said smaller blocks of said macroblocks of said bi-predicted pictures in said stream of pictures.  
     
     
         4 . The method of  claim 1 , further comprising encoding or decoding said predicted pictures in said stream of pictures in direct mode.  
     
     
         5 . The method of  claim 2 , further comprising deriving a forward motion vector and a backward motion vector for each of said smaller blocks of said macroblocks of said predicted pictures in said stream of pictures.  
     
     
         6 . The method of  claim 1 , further comprising calculating temporal differences that are used in derivations of motion vectors.  
     
     
         7 . The method of  claim 1 , further comprising encoding said pictures in said stream of pictures in multi-frame interpolative prediction mode.