Decoding and presentation time stamps for MPEG-4 advanced video coding

1. A method, comprising:

encoding a plurality of frames, wherein at least one of the plurality of encoded frames is predicted from another one of the plurality of encoded frames, with an encoder;

encoding a delay parameter in a sequence header of a hierarchical bitstream including the plurality of encoded frames, the hierarchical bitstream comprising the sequence header and a sequence payload, the sequence payload comprising a Group of Pictures Header and a plurality of Groups of Pictures, wherein each Group of Pictures further comprise a plurality of pictures and picture headers, wherein the delay parameter is a programmable re-ordering buffer delay determined based upon an encoding configuration of the encoder;

encoding a presentation time stamp with each of the plurality of encoded frames, wherein the presentation time stamp is a function of the delay parameter, a decode time stamp, and a number of frames between a first anchor frame of the plurality of frames and a second anchor frame of the plurality of frames; and

transmitting the hierarchical bitstream over a communication medium.

2. The method of claim 1 , further comprising encoding a decoding time stamp with each of said plurality of encoded frames.

3. The method of claim 1 , wherein the delay parameter is encoded with a variable length code.

4. The method of claim 1 , wherein the hierarchical bitstream comprises a variable time interval between pictures.

5. The method of claim 1 , wherein the plurality of pictures in each Group of Pictures is in data dependent order.

6. The method of claim 1 , further comprising packetizing the hierarchical bitstream into payloads of a plurality of transport packets for transmission over the communication medium.

7. The method of claim 6 , further comprising adding a program clock reference (PCR) time stamp to the plurality of transport packets for transmission over the communication medium.

8. An encoder, comprising:

a video compression engine for encoding a plurality of frames, wherein at least one of the plurality of encoded frames is predicted from another one of the plurality of encoded frames;

a header generator for encoding a delay parameter in a sequence header of a hierarchical bitstream including the plurality of encoded frames, the hierarchical bitstream comprising the sequence header and a sequence payload, the sequence payload comprising a Group of Pictures Header and a plurality of Groups of Pictures, wherein each Group of Pictures further comprise a plurality of pictures and picture headers, wherein the delay parameter is a programmable re-ordering buffer delay determined based upon an encoding configuration of the encoder; and

a packetizer for encoding a presentation time stamp with each of the plurality of encoded frames, wherein the presentation time stamp is a function of the delay parameter, a decode time stamp, and a number of frames between a first anchor frame of the plurality of frames and a second anchor frame of the plurality of frames.

9. The encoder of claim 8 , further comprising an output interface for transmitting the hierarchical bitstream over a communication medium.

10. The encoder of claim 8 , wherein the packetizer is further configured for encoding a decode time stamp with each of the plurality of encoded frames.

11. The encoder of claim 8 , wherein the presentation time stamp is a function of a picture type corresponding to the frame encoded with the presentation time stamp.

12. The encoder of claim 8 , wherein the plurality of pictures in each Group of Pictures is in data dependent order.

13. The encoder of claim 8 , wherein the first anchor frame and the second anchor frame comprise an I-picture and a P-picture.

14. The encoder of claim 13 , wherein the I-picture is an independent I-picture.

15. A method, comprising:

receiving, by a decoder, a hierarchical bitstream comprising a sequence header and a sequence payload, the sequence header comprising a delay parameter, the sequence payload comprising a Group of Pictures Header and a plurality of Groups of Pictures, wherein each Group of Pictures further comprise a plurality of encoded pictures and picture headers, the hierarchical bitstream including encoded frames having a presentation time stamp that is a function of the delay parameter, a decode time stamp, and a number of frames between a first anchor frame of a plurality of frames and a second anchor frame of a plurality of frames, wherein the delay parameter is a programmable re-ordering buffer delay determined based upon an encoding configuration of an encoder that encoded the Groups of Pictures;

determining whether a sequence end code or a sequence start code is present in the hierarchical bitstream;

in response to the determination, obtaining the delay parameter from the sequence header and determining a picture type for a next encoded picture of one of the plurality of Groups of Pictures; and

in response to the picture type of the next encoded picture being an independent I-picture, decoding the next encoded picture.

16. The method of claim 15 , further comprising refreshing a decoder buffer in response to a determination that a sequence end code is present.

17. The method of claim 15 , further comprising refreshing a decoder buffer in response to a determination that the next encoded picture is not an independent I-picture.

18. The method of claim 15 , further comprising, in response to a determination that a sequence start code is present, decoding the next encoded picture without obtaining the delay parameter.

19. The method of claim 15 , wherein the plurality of pictures in each Group of Pictures is in data dependent order.

20. The method of claim 15 , wherein the hierarchical bitstream comprises a variable time interval between pictures.