Method and device for lossy encoding data and corresponding device for reconstructing data

1. A method for lossy encoding data having at least one of image data or audio data, said method comprising:

determining quantized coefficients using a quantization of a discrete cosine transformed residual of a prediction of said data;

modifying said quantized coefficients for minimizing a rate-distortion cost, wherein distortion is determined using a post-processed reconstruction of the data, the post-processed reconstruction being post-processed according to a post-processing method; and

encoding said modified quantized coefficients;

wherein the post-processing method is that one of n>1 different given post processing method candidates whose position in an given order of arrangement of the post processing method candidates equals a remainder of division, by n, of a sum of the modified coefficients.

2. The method of claim 1 , wherein the reconstruction is determined using said modified coefficients and said prediction, said prediction being determined using already encoded data and a reference to the already encoded data is further encoded.

3. The method of claim 1 , wherein the modifying said quantized coefficients further comprises:

determining that a difference unequal to Zero exists between a remainder of division, by n, of a sum of the quantized coefficients and the position of that one of n different, ordered and given post processing method candidates which minimizes distortion when used for reconstructing said block using said quantized coefficients and said prediction; and

modifying the quantized coefficients such that overall modification equals the non-Zero difference.

4. The method of claim 3 , further comprising:

repeating said determining that a difference unequal to Zero exists and modifying the quantized coefficients such that overall modification equals the non-Zero difference; and

using in each repetition of said determining that a difference unequal to Zero exists the modified coefficients resulting from immediately preceding execution of said modifying the quantized coefficients such that overall modification equals the non-Zero difference until existence of a difference unequal to Zero is not determined.

5. The method of claim 1 , wherein the data and the quantized coefficients are arranged as two-dimensional blocks and said modifying the coefficients further comprises:

determining a sequence of coefficients by scanning the quantized coefficients according to a scan order and using the sequence for determining those quantized coefficients which each:

represents a frequency above a given frequency threshold,

does not exceed a given positive threshold, and

is the only non-Zero coefficient contained in contiguous subsequence of at least a given positive number of quantized coefficients, and

identifying, among the determined coefficients, those which, when set to zero, lead to minimization of rate-distortion cost and setting the identified coefficients to Zero.

6. The method of claim 5 , further comprising determining a quantization parameter for said quantization, wherein at least one of the positive threshold and the positive number depends on the determined quantization parameter.

7. The method of claim 1 , wherein one of the post processing method candidates comprises total variation regularization.

8. The method of claim 1 , wherein one of the post processing method candidates comprises 1 1 minimization.

9. The method of claim 1 , wherein one of the post processing method candidates comprises a dummy post processing method which does not process at all.

10. A method for reconstructing data having at least one of image data and audio data, said method comprising:

decoding coefficients;

determining a preliminary reconstruction of the data using the decoded coefficients; and

determining a reconstruction of the data by post-processing the preliminary reconstruction using that one of n>1 different given post processing method candidates whose position in an order of arrangement of the post processing method candidates equals a remainder of division, by n, of a sum of the decoded coefficients for minimizing a rate-distortion cost.

11. The method of claim 10 , wherein one of the post processing method candidates comprises total variation regularization.

12. The method of claim 10 , wherein one of the post processing method candidates comprises 1 1 minimization.

13. The method of claim 10 , wherein one of the post processing method candidates comprises a dummy post processing method which does not process at all.

14. Device for lossy encoding data having at least one of image data and audio data, comprising:

processing means adapted for determining quantized coefficients using a quantization of a discrete cosine transformed residual of a prediction of said data, the processing means being further adapted for modifying said quantized coefficients for minimizing a rate-distortion cost, wherein distortion is determined using a reconstruction of the block post-processed according to a post-processing method;

encoding means adapted for encoding said modified coefficients wherein the post-processing method used for distortion determination is that one of n>1 different given post processing method candidates whose position in an given order of arrangement of the post processing method candidates equals a remainder of division, by n, of a sum of the modified coefficients.

15. A device for reconstructing data having at least one of image data and audio data, comprising:

decoding means adapted for decoding coefficients; and

processing means adapted for determining a preliminary reconstruction of the data using the decoded coefficients;

wherein the processing means are further adapted for determining a reconstruction of the block by post-processing the preliminary reconstruction using that one of n>1 different given post processing method candidates whose position in an order of arrangement of the post processing method candidates equals a remainder of division, by n, of a sum of the decoded coefficients for minimizing a rate-distortion cost.