Granted Patent E1

US 46,370 · App. 14/207,043 · Granted Apr 18, 2017

Inventor: Louis J. Kerofsky (Camas, WA)

Assignee: Dolby Laboratories Licensing Corporation

H03M7/24H04N19/136

Abstract

Claims (46)

1. A method for dequantization and inverse transformation, said method comprising:

(a) receiving a matrix of quantized coefficient levels;

(b) receiving at least one quantization parameter (QP);

(c) determining a reconstructed transform coefficient (RTC) matrix wherein each value in said quantized coefficient level matrix is scaled by a value in a scaling matrix which is dependent on QP % P, where P is a constant value;

(d) computing scaled reconstructed samples (SRS) by performing an inverse transformation on said RTC matrix values; and

(e) computing reconstructed samples, by normalizing the SRS values.

2. A method as described in claim 1 wherein P=6.

3. A method as described in claim 1 wherein said scaling matrix is a 4×4 matrix.

4. A method as described in claim 1 wherein said scaling matrix is an 8×8 matrix.

5. A method as described in claim 1 wherein said at least one quantization parameter (QP) comprises a chroma quantization parameter.

6. A method as described in claim 1 wherein said at least one quantization parameter (QP) comprises a luma quantization parameter.

7. A method as described in claim 1 wherein said at least one quantization parameter (QP) comprises a chroma quantization parameter for each chroma channel.

8. A method as described in claim 1 wherein said at least one quantization parameter (QP) comprises a chroma quantization parameter for each chroma channel and a luma quantization parameter.

9. A method for dequantization and inverse transformation, said method comprising:

(a) receiving a matrix of quantized coefficient levels (QCL matrix);

(b) receiving a quantization parameter (QP);

(c) calculating a scaling matrix using a weighting matrix scaled by a dequantization matrix selected using QP % P;

(d) determining a reconstructed transform coefficient (RTC) matrix wherein said QCL matrix is scaled by said scaling matrix;

(e) computing scaled reconstructed samples (SRS) by performing an inverse transformation on said RTC matrix values; and

(f) computing reconstructed samples, by normalizing the SRS values with a constant shift operation.

10. A method as described in claim 9 further comprising shifting said RTC matrix values by a value dependent on QP/P before said computing scaled reconstructed samples.

11. A method for dequantization and inverse transformation, said method comprising:

(a) fixing a limited set of scaling matrices, wherein each of said scaling matrices in said limited set of scaling matrices is dependent on an associated quantization parameter QP and an associated constant parameter P according to the relation QP % P;

(b) receiving a quantized coefficient level (QCL) matrix;

(c) determining a reconstructed transform coefficient (RTC) matrix wherein each value in said quantized coefficient level matrix is scaled by a value in a scaling matrix that is selected from said limited set of scaling matrices;

(d) computing scaled reconstructed samples (SRS) by performing an inverse transformation on said RTC matrix values; and

(e) computing reconstructed samples, by normalizing the SRS values.

12. An apparatus for dequantization and inverse transformation, said apparatus comprising:

(a) a QCL receiver for receiving a matrix of quantized coefficient levels (QCLs);

(b) a QP receiver for receiving at least one quantisation parameter (QP);

(c) a processor, wherein said processor is capable of determining a reconstructed transform coefficient (RTC) matrix wherein each value in said quantized coefficient level matrix is scaled by a value in a scaling matrix which is dependent on QP % P, where P is a constant value;

(d) said processor comprising a further capability of computing scaled reconstructed samples (SRS) by performing an inverse transformation on said RTC matrix values; and

(e) said processor comprising the capability of computing reconstructed samples, by normalizing said SRS values.

13. A computer-readable medium encoded with computer executable instructions for dequantization and inverse transformation, said instructions comprising:

(a) receiving a matrix of quantized coefficient levels;

(b) receiving at least one quantization parameter (QP);

(c) determining a reconstructed transform coefficient (RTC) matrix wherein each value in said quantized coefficient level matrix is scaled by a value in a scaling matrix which is dependent on QP % P, where P is a constant value;

(d) computing scaled reconstructed samples (SRS) by performing an inverse transformation on said RTC matrix values; and

(e) computing reconstructed samples, by normalizing the SRS values.

14. A non-transitory computer-readable medium encoded with executable instructions for a video decoder comprising one or more processors, said instructions comprising:

(a) receiving a matrix L of quantized coefficient levels by a decoder;

(b) receiving at least one quantization parameter (QP);

(c) determining a transform coefficient matrix K, wherein an element K[i][j] of the matrix K is determined by scaling an element L[i][j] in said matrix L of quantized coefficient levels according to the following equation:

K[i][j]=L[i][j]×B(QP mod P)[i][j]×2B0+QP/P, where B(QP mod P)[i][j] is a mantissa portion that is a function of the quantization parameter QP and P is a constant value;

(d) inverse transforming the transform coefficient matrix K to generate reconstructed pixel samples; and

(e) generating a portion of an image based on the reconstructed pixel samples.

Assignments (1)

Continuity (10)