# US 2019/0320175 A1 · Video coding method, computer device, and storage medium

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- Number: US 2019/0320175 A1
- Document ID: US20190320175A1
- Status: Published application
- Kind: A1
- Application number: 16/450,705
- Filed: 2019-06-24
- Published: 2019-10-17
- Earliest claimed: 2017-11-21
- Assignees: Tencent Technology (Shenzhen) Company Limited
- Applicants: Tencent Technology (Shenzhen) Company Limited
- Inventors: Xunan MAO
- Web page: https://patentgrep.com/patent/US20190320175A1

## CPC

- H04N 19/126: Details of normalisation or weighting functions, e.g. normalisation matrices or variable uniform quantisers
- H04N 19/14: Coding unit complexity, e.g. amount of activity or edge presence estimation (H04N19/146 takes precedence)
- H04N 19/114: Adapting the group of pictures [GOP] structure, e.g. number of B-frames between two anchor frames (H04N19/107 takes precedence)
- H04N 19/124: Quantisation
- H04N 19/146: Data rate or code amount at the encoder output
- H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
- H04N 19/172: the region being a picture, frame or field
- H04N 19/187: the unit being a scalable video layer
- H04N 19/463: by compressing encoding parameters before transmission
- H04N 19/573: Motion compensation with multiple frame prediction using two or more reference frames in a given prediction direction
- H04N 19/577: Motion compensation with bidirectional frame interpolation, i.e. using B-pictures
- H04N 19/30: using hierarchical techniques, e.g. scalability (H04N19/63 takes precedence)
- H04N 19/31: in the temporal domain
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

A video coding method can include receiving, by processing circuitry of a coding device, a current picture in a group of pictures (GOP) of a layered coding structure in video sequence. The current picture can have two reference pictures. A current layer of the current picture in the layered coding structure can be determined. A current quantization parameter (QP) offset of the current picture can be determined according to the current layer of the current picture. Reference QPs corresponding to the two reference pictures of the current picture can be determined. A current QP of the current picture can be determined according to the reference QPs and the current QP offset. The current picture can be coded according to the current QP.

## Claims

### Claim 1

A video coding method, comprising:
receiving, by processing circuitry of a coding device, a current picture in a group of pictures (GOP) of a layered coding structure in video sequence, the current picture having two reference pictures;
determining, by the processing circuitry, a current layer of the current picture in the layered coding structure;
determining, by the processing circuitry, a current quantization parameter (QP) offset of the current picture according to the current layer of the current picture;
determining, by the processing circuitry, reference QPs corresponding to the two reference pictures of the current picture;
determining, by the processing circuitry, a current QP of the current picture according to the reference QPs and the current QP offset; and
coding the current picture according to the current QP.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the two reference pictures are B frames, and the determining the current QP of the current picture comprises:
determining a first distance between a first reference picture of the two reference pictures and the current picture, and a second distance between a second reference picture of the two reference pictures and the current picture;
determining a first QP based on the first and second distances and the reference QPs of the two reference pictures; and
determining the current QP of the current picture based on a sum of the first QP and the current QP offset.

### Claim 3 (depends on 2)

The method according to claim 2, wherein the determining the first QP comprises:
determining the first QP based on a weighted sum of the reference QPs of the two reference pictures based on a first weight and a second weight,
wherein the first weight corresponds to the first reference picture, and is a first ratio of the second distance to a sum of the first and second distances, and
the second weight corresponds to the second reference picture, and is a second ratio of the first distance to the sum of the first and second distances.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the two reference pictures are I frames, and the determining the current QP of the current picture comprises:
determining an average of the reference QPs of the two reference pictures;
determining a second QP that is a sum of the average and a predetermined value; and
determining the current QP of the current picture based on a sum of the second QP and the current QP offset.

### Claim 5 (depends on 1)

The method according to claim 1, wherein a first reference picture of the two reference pictures is an I frame, and a second reference picture of the two reference pictures is a P frame or B frame, and the determining the current QP of the current picture comprises:
determining a third QP that is the QP of the second reference picture; and
determining the current QP of the current picture to be a sum of the third QP and the current QP offset.

### Claim 6 (depends on 1)

The method according to claim 1, wherein the determining the reference QPs comprises:
determining a type and a QP of a first reference picture of the two reference pictures, the type being one of I frame, P frame, and B frame; and
determining the reference QP of the first reference picture according to the type and the QP of the first reference picture, the reference QP of the first reference picture being one of the reference QPs.

### Claim 7 (depends on 6)

The method according to claim 6, wherein the determining the reference QP of the first reference picture comprises:
when the type of the first reference picture is B frame,
determining a layer of the first reference picture in the layer coding structure;
determining a reference QP offset corresponding to the first reference picture according to the layer of the first reference picture; and
determining the reference QP of the first reference picture based on a difference between the QP of the first reference picture and the reference QP offset of the first reference picture.

### Claim 8 (depends on 6)

The method according to claim 6, wherein the determining the reference QP of the first reference picture comprises:
when the type of the first reference picture is I frame or P frame,
determining a QP of the first reference picture to be the first reference QP.

### Claim 9 (depends on 1)

The method according to claim 1, wherein the coding the current picture comprises:
determining a current quantization step corresponding to the current picture according to the current QP; and
coding the current picture frame according to the current quantization step to obtain a current bit rate corresponding to the current picture.

### Claim 10 (depends on 9)

The method according to claim 9, further comprising:
determining a quantization offset parameter of the current layer of the current picture with respect to a unidirectionally predicted picture in the GOP;
determining a complexity update value according to the current bit rate of the current picture and the quantization offset parameter; and
determining an updated picture complexity parameter according to a picture complexity parameter of a preceding picture frame of the current picture frame and the picture complexity update value.

### Claim 11 (depends on 10)

The method according to claim 10, further comprising:
determining a type of a subsequent picture that is coded after the current picture; and
when the subsequent picture is a non-bidirectionally predicted picture, determining a QP corresponding to the subsequent picture according to a bit rate control model and the updated picture complexity parameter.

### Claim 12 (depends on 1)

The method according to claim 1, wherein the determining the current QP offset comprises:
determining a quantization offset parameter of the current layer with respect to a unidirectionally predicted picture in the GOP; and
determining the current QP offset according to the quantization offset parameter.

### Claim 13 (depends on 12)

The method according to claim 12, wherein a first layer in the layered coding structure that is higher than a second layer in the layered coding structure has a higher quantization offset parameter.

### Claim 14

An apparatus of video coding, comprising circuitry configured to:
receive a current picture in a group of pictures (GOP) of a layered coding structure in video sequence, the current picture having two reference pictures;
determine a current layer of the current picture in the layered coding structure;
determine a current quantization parameter (QP) offset of the current picture according to the current layer of the current picture;
determine reference QPs corresponding to the two reference pictures of the current picture;
determine a current QP of the current picture according to the reference QPs and the current QP offset; and
coding the current picture according to the current QP.

### Claim 15

A non-transitory computer-readable medium storing a program executable by a processor to perform a method, the method comprising:
receiving a current picture in a group of pictures (GOP) of a layered coding structure in video sequence, the current picture having two reference pictures;
determining a current layer of the current picture in the layered coding structure;
determining a current quantization parameter (QP) offset of the current picture according to the current layer of the current picture;
determining reference QPs corresponding to the two reference pictures of the current picture;
determining a current QP of the current picture according to the reference QPs and the current QP offset; and
coding the current picture according to the current QP.

### Claim 16 (depends on 15)

The non-transitory computer-readable medium according to claim 15, wherein the method further comprises:
determining a first distance between a first reference picture of the two reference pictures and the current picture, and a second distance between a second reference picture of the two reference pictures and the current picture;
determining a first QP based on the first and second distances and the reference QPs of the two reference pictures; and
determining the current QP of the current picture based on a sum of the first QP and the current QP offset.

### Claim 17 (depends on 16)

The non-transitory computer-readable medium according to claim 16, wherein the determining the first QP comprises:
determining the first QP based on a weighted sum of the reference QPs of the two reference pictures based on a first weight and a second weight,
wherein the first weight corresponds to the first reference picture, and is a first ratio of the second distance to a sum of the first and second distances, and
the second weight corresponds to the second reference picture, and is a second ratio of the first distance to the sum of the first and second distances.

### Claim 18 (depends on 14)

The non-transitory computer-readable medium according to claim 14, wherein the two reference pictures are I frames, and the determining the current QP of the current picture comprises:
determining an average of the reference QPs of the two reference pictures;
determining a second QP that is a sum of the average and a predetermined value; and
determining the current QP of the current picture based on a sum of the second QP and the current QP offset.

### Claim 19 (depends on 14)

The non-transitory computer-readable medium according to claim 14, wherein a first reference picture of the two reference pictures is an I frame, and a second reference picture of the two reference pictures is a P frame or B frame, and the determining the current QP of the current picture comprises:
determining a third QP that is the QP of the second reference picture; and
determining the current QP of the current picture to be a sum of the third QP and the current QP offset.

### Claim 20 (depends on 14)

The non-transitory computer-readable medium according to claim 14, wherein the determining the reference QPs comprises:
determining a type and a QP of a first reference picture of the two reference pictures, the type being one of I frame, P frame, and B frame; and
determining the reference QP of the first reference picture according to the type and the QP of the first reference picture, the reference QP of the first reference picture being one of the reference QPs.