13. The apparatus of claim 12 further comprising: a graphics overlay generator responsive to said closed captioning data bytes for generating closed captioning text from said extracted closed captioning bytes and displaying a decoded picture, with closed captioning text generated from said closed captioning data bytes overlaid thereon, on a monitor.
12. An apparatus for parsing closed captioning data encoded according to one of at least three syntaxes, comprising: a parser input for receiving an encoded video signal which is hierarchically organized into picture sections of a picture layer, each picture section containing an encoded picture and at least one corresponding user data section, and a parser for identifying a beginning of a sequence of bits of said user data section within one of said picture sections, for determining if said identified sequence of bits contains either undefined data or closed captioning data encoded according to either a specific first syntax or closed captioning data encoded according to a specific second syntax, but not closed captioning data encoded according to any of said other syntaxes, and, if said determination is affirmative, for: (1) extracting a byte from a beginning of said sequence representing a user data length, and a byte following said user data length byte in said sequence, representing a user data type, and (2) if said user data length byte equals a first predefined constant or a second predefined constant, different from the first predefined constant, which first and second constants indicate the presence of two closed captioning bytes according to said first and second syntaxes, respectively, and said user data type byte equals a third predefined constant, then immediately following said user data type byte in said sequence, extracting exactly two closed captioning bytes for said corresponding picture.