Reference picture management in video coding

• US 20060083298A1
• Filed: 04/26/2005
• Published: 04/20/2006
• Est. Priority Date: 10/14/2004
• Status: Abandoned Application

• Current Assignee: Nokia Corporation
• Original Assignee: Nokia Corporation
• Inventors: Wang, Ye-Kui, Hannuksela, Miska
• Application Number:
  US11/116,109
• Publication Number:
  US 20060083298A1
• Time in Patent Office: Days
• US Class Current: 375/240.10
• CPC Class Codes: H04N 19/196 being specially adapted for the computation of encoding parameters, e.g. by averaging previously computed encoding parameters processing of motion vectors H04N19/513
• CPC Class Codes: H04N 19/463 by compressing encoding parameters before transmission
• CPC Class Codes: H04N 19/573 Motion compensation with multiple frame prediction using two or more reference frames in a given prediction direction
• CPC Class Codes: H04N 19/58 Motion compensation with long-term prediction, i.e. the reference frame for a current frame not being the temporally closest one H04N19/23 takes precedence

Abstract

A method for encoding a sequence of pictures comprising using one or more pictures as reference pictures, labeling the reference pictures with a first parameter, signaling the first parameter to a decoder, and using a reference picture management, wherein all the reference pictures are identified by a second parameter which is derived on the basis of the first parameter.

Claims

1. A method for encoding a sequence of pictures comprising:

using one or more pictures as reference pictures;

labeling the reference pictures with a first parameter;

signaling the first parameter to a decoder; and

using a reference picture management;

wherein all the reference pictures are identified by a second parameter which is derived on the basis of the first parameter.

2. A method according to claim 1 comprising

using a frame number FN as said first parameter, and

using a reference picture number RPN as said second parameter.

3. A method according to claim 2 comprising

defining a decoding order for pictures of said sequence of pictures;

defining a parameter prevFN equal to the frame number of the previous reference picture in said decoding order;

defining a parameter prevRPN equal to the reference picture number of the previous reference picture;

defining a maximum value for the frame number;

defining a parameter maxFNplus1 equal to said maximum value for the frame number+1; and

calculating the reference picture number of the reference picture as follows;

if(prevFN <

= FN) 

RPN = prevRPN + FN −

prevFNelse 

RPN = prevRPN + FN −

prevFN + maxFNplus1

4. A method according to claim 1, the reference picture management comprising reference picture list initialization and reference picture list reordering.

5. A method according to claim 4 comprising signaling

a parameter AbsDIFFminus1 indicative of the absolute difference between the prediction of the RPN and the RPN value, wherein the prediction of the RPN is an expected value of the RPN;

a parameter ASidc indicative of whether the absolute difference is added to or subtracted from the prediction value of the RPN to derive the RPN value; and

a parameter PS indicative of the scale of the prediction value of the RPN.

6. A method according to claim 5 comprising

setting a parameter RPNcurr to the value of the RPN of a first to-be-reordered reference picture;

calculating the prediction value predRPN for the first to-be-reordered reference picture as follows;

predRPN=RPNcurr−

PS*MaxFNplus1

setting the prediction value predRPN first equal to PRN value of the previous reordered reference picture; and

updating the predRPN as follows;

if(ASidc ==

     0) 

predRPN = predRPN −

PS * MaxFNplus1else if(PNidc ==

     1) 

predRPN = predRPN + PS * MaxFNplus1

7. A method according to claim 1, the reference picture management comprising reference picture marking.

8. A method according to claim 7 comprising signaling

a parameter diffPRNminus1 indicative of the difference between the prediction of the RPN and the RPN value of the to-be-marked reference picture minus 1;

and

a parameter PS indicative of the scale of the prediction value.

9. A method according to claim 8 comprising

setting a parameter RPNcurr to the value of the RPN of a to-be-marked reference picture;

and

calculating the reference picture number value RPN for the to-be-marked reference picture as follows;

$\begin{array}{c}\mathrm{RPN}=\mathrm{predRPN}-\left(\mathrm{diff}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{RPN}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{minus}<br><br>\text{\hspace{1em}<br><br>}<br><br>1+1\right)\\ =\mathrm{RPN}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{curr}-\mathrm{PS}*\mathrm{Max}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{FNplus}<br><br>\text{\hspace{1em}<br><br>}<br><br>1-\left(\mathrm{diffRPN}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{minus}<br><br>\text{\hspace{1em}<br><br>}<br><br>1+1\right)\end{array}$

14. A signal comprising a sequence of encoded pictures;

said sequence comprising one or more reference pictures, said reference pictures being labeled with a first parameter;

said signal being used according to claim 1.

15. A hardware for implementing claim 1.

10. A method for decoding a sequence of encoded pictures comprising:

using one or more pictures as reference pictures, said reference pictures being labeled with a first parameter;

obtaining the first parameter from the encoded pictures; and

using a reference picture management;

wherein all the reference pictures are identified by a second parameter which is derived on the basis of the first parameter.

11. A method according to claim 10, the reference picture management comprising reference picture list initialization and reference picture list reordering.

12. A method according to claim 10, the reference picture management comprising reference picture marking.

13. A method according to claim 10, the reference picture management comprising reference picture reordering and reference picture marking.

16. A module for encoding a sequence of pictures comprising:

a first element for selecting one or more pictures to be used as reference pictures;

a second element for labeling the reference pictures with a first parameter;

a third element for including the first parameter in a signal to be transmitted to a decoder; and

a fourth element for derivation of a second parameter based on the first parameter;

wherein all the reference pictures are identified by the second parameter.

17. A module according to claim 16 wherein the module is included in a wireless device.

18. A module for decoding a sequence of encoded pictures, the pictures comprising one or more pictures as reference pictures, said reference pictures being labeled with a first parameter;

the module comprising;

a first element for obtaining the first parameter from the encoded pictures;

a reference picture manager; and

a second element for deriving a second parameter on the basis of the first parameter for identifying all the reference pictures.

19. A module according to claim 18 wherein the module is included in a wireless device.

20. A system comprising:

an encoding device for encoding a sequence of pictures comprising;

a first element for selecting one or more pictures to be used as reference pictures;

a second element for labeling the reference pictures with a first parameter;

a third element for including the first parameter in a signal to be transmitted to a decoder;

a fourth element for derivation of a second parameter based on the first parameter;

wherein all the reference pictures are identified by the second parameter;

a decoding device for decoding the signal, the decoding device comprising

a fifth element for obtaining the first parameter from the encoded pictures;

a reference picture manager; and

a sixth element for deriving a second parameter on the basis of the first parameter for identifying all the reference pictures.

21. A computer program product comprising software for encoding a sequence of pictures, the software comprising machine executable code stored on a readable medium for execution by a processor, the machine executable code for:

using one or more pictures as reference pictures;

labeling the reference pictures with a first parameter;

including the first parameter in a signal to be transmitted; and

deriving of a second parameter based on the first parameter;

wherein all the reference pictures are identified by the second parameter

22. A computer program product comprising software for decoding a sequence of pictures, the software comprising machine executable code stored on a readable medium for execution by a processor, the machine executable code for:

using one or more pictures as reference pictures, said reference pictures being labeled with a first parameter;

obtaining the first parameter from the encoded pictures;

using a reference picture management; and

deriving a second parameter on the basis of the first parameter; and

identifying all the reference pictures by said second parameter.