VIDEO DECODER WITH REDUCED DYNAMIC RANGE TRANSFORM WITH QUANTIZATION MATRICIES

• US 20120230395A1
• Filed: 03/11/2011
• Published: 09/13/2012
• Est. Priority Date: 03/11/2011
• Status: Abandoned Application

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Kerofsky, Louis Joseph, Misra, Kiran, Segall, Christopher Andrew
• Application Number:
  US13/046,514
• Publication Number:
  US 20120230395A1
• Time in Patent Office: Days
• US Class Current: 375/240.03
• CPC Class Codes: H04N 19/122 Selection of transform size, e.g. 8x8 or 2x4x8 DCT; Selection of sub-band transforms of varying structure or type
• CPC Class Codes: H04N 19/126 Details of normalisation or weighting functions, e.g. normalisation matrices or variable uniform quantisers
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/184 the unit being bits, e.g. of the compressed video stream
• CPC Class Codes: H04N 19/42 characterised by implementation details or hardware specially adapted for video compression or decompression, e.g. dedicated software implementation H04N19/635 takes precedence
• CPC Class Codes: H04N 19/44 Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• CPC Class Codes: H04N 19/61 in combination with predictive coding

Abstract

A method for decoding video comprising receiving quantized coefficients representative of a block of video representative of a plurality of pixels. The quantized coefficients are dequantized and applying a modification to the dequantized coefficients based upon a quantization matrix. Then inverse transforming the dequanized coefficients to determine a decoded residue.

Claims

1. A method for decoding video comprising:

(a) receiving quantized coefficients representative of a block of video representative of a plurality of pixels;

(b) dequantizing said quantized coefficients;

(c) applying a modification to said dequantized coefficients based upon a quantization matrix;

(d) inverse transforming said dequanized coefficients to determine a decoded residue.

2. The method of claim 1 wherein said dequantizing is based upon a coefficient index, a bit increment, a transform size, and said quantization matrix.

3. The method of claim 1 wherein said modification is based upon a coefficient index, a bit increment, a transform size, and said quantization matrix

4. The method of claim 1 wherein said modification is based upon 2^(QP/6+B), where QP is a quantization matrix, and B relates to a transform size.

5. The method of claim 1 wherein said modified dequantized coefficients are clipped prior to storing in a memory and said clipped coefficients are read from said memory for said inverse transforming.

6. The method of claim 1 wherein said dequantization and said modification of said dequantized coefficients are jointly based upon said quantization matrix.

7. The method of claim 6 wherein said modification is a shift operation.

8. The method of claim 7 wherein said dequantized coefficients are clipped prior to said modification.

9. The method of claim 8 wherein said modification is based upon a single value based upon said quantization matrix.

10. The method of claim 9 wherein said single value is based upon a minimum function.

11. The method of claim 10 further comprising another modification operating on said dequantized coefficients based upon said quantization matrix and the resulting data is subsequently said clipped.

12. The method of claim 1 wherein said dequantized coefficients are further modified as a result of an adjustment mechanism.

13. The method of claim 12 wherein said adjustment mechanism is a variable dependent on transform size.

14. The method of claim 12 wherein said adjustment mechanism is a function of at least one of a received quantization parameter and a transform size.