# US 10,375,390 B2 · Method and apparatus of deriving intra prediction mode using most probable mode group

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 10,375,390 B2
- Document ID: US10375390B2
- Status: Granted
- Kind: B2
- Application number: 15/332,325
- Filed: 2016-10-24
- Published: 2017-02-09
- Granted: 2019-08-06
- Earliest claimed: 2011-11-04
- Assignees: Infobridge Pte. Ltd.
- Applicants: Infobridge Pte. Ltd.
- Inventors: Soo Mi Oh; Moonock Yang
- Web page: https://patentgrep.com/patent/US10375390B2

## CPC

- H04N 19/11: among a plurality of spatial predictive coding modes
- H04N 19/103: Selection of coding mode or of prediction mode
- H04N 19/117: Filters, e.g. for pre-processing or post-processing (sub-band filter banks H04N19/635)
- H04N 19/122: Selection of transform size, e.g. 8x8 or 2x4x8 DCT; Selection of sub-band transforms of varying structure or type
- H04N 19/124: Quantisation
- H04N 19/129: Scanning of coding units, e.g. zig-zag scan of transform coefficients or flexible macroblock ordering [FMO]
- H04N 19/157: Assigned coding mode, i.e. the coding mode being predefined or preselected to be further used for selection of another element or parameter
- H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
- H04N 19/176: the region being a block, e.g. a macroblock
- H04N 19/44: Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
- H04N 19/46: Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence)
- H04N 19/463: by compressing encoding parameters before transmission
- H04N 19/593: involving spatial prediction techniques
- H04N 19/61: in combination with predictive coding
- H04N 19/625: using discrete cosine transform [DCT]
- H04N 19/86: involving reduction of coding artifacts, e.g. of blockiness
- H04N 19/91: Entropy coding, e.g. variable length coding [VLC] or arithmetic coding
- H04N 19/172: the region being a picture, frame or field
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

An image encoding apparatus is presented. A differential quantization parameter is generated by subtracting a quantization parameter predictor from a quantization parameter, and is entropy-coded. If two or more quantization parameters are available among a left quantization parameter, an above quantization parameter and a previous quantization parameter of a current coding unit, the quantization parameter predictor is generated using two available quantization parameters determined according a predetermined order, and if only one quantization parameter is available, the available quantization parameter is set as the quantization parameter predictor. A transform type for inversely transforming the residual signals is selected among a discrete cosine transform (DCT)-based integer transform and a discrete sign transform (DST)-based integer transform based on a prediction mode and a size of a transform unit.

## Claims

### Claim 1

An image encoding apparatus comprising:
an intra predictor to determine an intra prediction mode of a current prediction unit and generate a prediction block using the intra prediction mode;
an inter predictor to determine motion information and generate a prediction block;
a transformer to transform residual signals generated by using an original block and the prediction block to generate a transformed block;
a quantizer to determine a quantization parameter and quantize the transformed block using a quantization matrix and the quantization parameter to generate a quantized block;
a scanner to determine a scan pattern and apply the scan pattern to significant coefficients, sign flags and levels of the quantized block;
an entropy coder to entropy-code one-dimensional coefficient information received from the scanner, intra prediction information received from the intra predictor, and motion information received from the inter predictor;
an inverse quantizer to inversely quantize the quantized block;
an inverse transformer to inversely transform the inversely quantized block to generate a residual block;
an adder to generate a reconstructed block by adding the residual block and the prediction block; and
a post-processor to remove blocking artifact in a reconstructed picture,
wherein a differential quantization parameter is generated by subtracting a quantization parameter predictor from the quantization parameter, and is entropy-coded,
wherein,
if two or more quantization parameters are available among a left quantization parameter, an above quantization parameter and a previous quantization parameter of a current coding unit, the quantization parameter predictor is generated using two available quantization parameters determined according a predetermined order among the left quantization parameter, the above quantization parameter and the previous quantization parameter,
if the left quantization parameter is not available among the left quantization parameter, the above quantization parameter and the previous quantization parameter, an average of the above quantization parameter and the previous quantization parameter is set as the quantization parameter predictor, and
if only one quantization parameter is available among the left quantization parameter, the above quantization parameter and the previous quantization parameter, the available quantization parameter is set as the quantization parameter predictor, and
wherein a transform type for inversely transforming the residual signals is selected among a discrete cosine transform (DCT)-based integer transform and a discrete sine transform (DST)-based integer transform based on a prediction mode and a size of a transform unit.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein a size of the prediction block generated by the intra predictor is equal to a size of a transform unit, and plural prediction blocks are generated by the intra predictor using the intra prediction mode if a size of the current prediction unit is larger than the size of the transform unit.

### Claim 3 (depends on 1)

The apparatus of claim 1, wherein if the left and above quantization parameters are available, an average of the left and above quantization parameters is set as the quantization parameter predictor.

### Claim 4 (depends on 1)

The apparatus of claim 1, wherein the quantization parameter is generated per quantization unit, and a minimum size of the quantization unit is adjusted per picture.

### Claim 5 (depends on 1)

The apparatus of claim 1, wherein the quantizer has a size of a coding unit equal to or larger than a reference size, and the reference size is a minimum size of a quantization unit.

### Claim 6 (depends on 5)

The apparatus of claim 5, wherein the minimum size of the quantization unit is one of allowable sizes of the coding unit.

### Claim 7 (depends on 1)

The apparatus of claim 1, wherein the scan pattern is determined by the intra prediction mode and the size of the transform unit in intra prediction.

### Claim 8 (depends on 7)

The apparatus of claim 7, wherein if the size of the transform unit is larger than 4×4, the quantized block is divided into a plurality of subsets, the scan pattern is applied to the plurality of subsets, and non-zero subset flags are determined and encoded.

### Claim 9 (depends on 8)

The apparatus of claim 8, wherein the non-zero subset flag indicates whether the subset contains non-zero coefficients or not.