Method and apparatus for variable accuracy inter-picture timing specification for digital video encoding
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.
1. A method of specifying digital video information, said method comprising:
determining a first display time difference between a first video picture and a nearby video picture; and
encoding said first video picture and said first display time difference into a first digitally encoded video picture, wherein said first display time difference is encoded more than once in said first digitally encoded video picture.
2. The method of specifying digital video information as claimed in claim 1 , said method further comprising:
transmitting said first digitally encoded video picture including said first display time difference.
3. The method of specifying digital video information as claimed in claim 1 wherein said nearby video picture comprises a most recently transmitted stored picture.
4. The method of specifying digital video information as claimed in claim 1 wherein said first display time difference is encoded into a slice header of said digitally encoded video picture.
5. The method of specifying digital video information as claimed in claim 1 wherein said first display time difference comprises a relative time value.
6. The method of specifying digital video information as claimed in claim 1 wherein said first display time difference is encoded as a power of two.
7. The method of specifying digital video information as claimed in claim 1 wherein said first display time difference is encoded with a variable length coding.
8. The method of specifying digital video information as claimed in claim 1 wherein said first display time difference is encoded with arithmetic coding.
9. The method of specifying digital video information as claimed in claim 1 wherein said first display time difference comprises a signed integer.
10. An encoding system for encoding digital video information, said encoding system comprising:
a first digitally encoded video picture comprising an encoding of a first video picture; and
a first display time difference, said first display time difference specifying a difference between a display time of said first video picture and a display time of a nearby video picture;
wherein said first display time difference is encoded within said first digitally encoded video picture, wherein said first display time difference is encoded more than once in said first digitally encoded video picture.
11. The encoding system for encoding digital video information as claimed in claim 10 wherein said nearby video picture comprises a most recently transmitted stored picture.
12. The encoding system for encoding digital video information as claimed in claim 10 wherein said first display time difference is encoded into a slice header of said first digitally encoded video picture.
13. The encoding system for encoding digital video information as claimed in claim 10 wherein said first display time difference comprises a relative time value.
14. The encoding system for encoding digital video information as claimed in claim 10 wherein said first display time difference is encoded as a power of two.
15. The encoding system for encoding digital video information as claimed in claim 10 wherein said first display time difference is encoded with a variable length coding.
16. The encoding system for encoding digital video information as claimed in claim 10 wherein said first display time difference is encoded with arithmetic coding.
17. The encoding system for encoding digital video information as claimed in claim 10 wherein said first display time difference comprises a signed integer.