A method and apparatus for variable accuracy inter-picture timing
specification for digital video encoding is disclosed. Specifically, the
present invention discloses a system that allows the relative timing of
nearby video pictures to be encoded in a very efficient manner. In one
embodiment, the display time difference between a current video picture
and a nearby video picture is determined. The display time difference is
then encoded into a digital representation of the video picture. In a
preferred embodiment, the nearby video picture is the most recently
transmitted stored picture. For coding efficiency, the display time
difference may be encoded using a variable length coding system or
arithmetic coding. In an alternate embodiment, the display time
difference is encoded as a power of two to reduce the number of bits
transmitted.