Video encoding method and apparatus, storage medium, and device

Patent metadata

Field	Value
Publication number	US-11388403-B2
Application number	US-202016996443-A
Country	US
Kind code	B2
Filing date	Aug 18, 2020
Priority date	Apr 27, 2018
Publication date	Jul 12, 2022
Grant date	Jul 12, 2022

Abstract

In a video encoding method, a to-be-encoded video is obtained. The video includes at least two video frames arranged in sequence. A quantization parameter and a quantization parameter threshold of an ith video frame is calculated, where i is a positive integer greater than or equal to 2. A coding resolution of the ith video frame is determined according to the quantization parameter and the quantization parameter threshold. The coding resolution is a first coding resolution in a case that the ith video frame is sampled, and the coding resolution is a second coding resolution in a case that the ith video frame is downsampled. Then the ith video frame is encoded at the coding resolution.

First claim

What is claimed is:

1. A video encoding method, comprising:
obtaining, by circuitry of a terminal, a to-be-encoded video, the video including at least two video frames arranged in sequence;
calculating, by the circuitry of the terminal and for an i th video frame in the at least two video frames, a quantization parameter and a quantization parameter threshold of the i th video frame, i being a positive integer greater than or equal to 2;
determining, by the circuitry of the terminal, a coding resolution of the i th video frame according to the quantization parameter and the quantization parameter threshold, the coding resolution being a first coding resolution or a second coding resolution, the first coding resolution being a resolution in a case that the i th video frame is sampled, and the second coding resolution being a resolution in a case that the i th video frame is downsampled; and
encoding, by the circuitry of the terminal, the i th video frame at the coding resolution,
wherein, in a case that there are two threshold sets and the two threshold sets correspond to different coding resolutions, the determining, comprises:
determining a quantization parameter according to a coding cost ratio between a first coding cost based on the i th video frame being an I frame and a second coding cost based on the i th frame being a P frame, the two threshold sets, and the first coding resolution in a case that the coding resolution of the i th video frame is assumed to be the first coding resolution during calculation of the quantization parameter; and
determining the quantization threshold parameter according to the coding cost ratio, the two threshold sets, and the second coding resolution in a case that the coding resolution of the i th video frame is assumed to be the second coding resolution during calculation of the quantization parameter.

2. The method according to claim 1 , wherein the calculating a quantization parameter of the i th video frame comprises:
reading a specified quantization parameter;
determining the quantization parameter as the quantization parameter of the i th video frame in a case that a coding mode of the i th video frame is a fixed-quality coding mode;
calculating a quantization parameter of a first coding block in the i th video frame; and
determining the quantization parameter of the first coding block as the quantization parameter of the i th video frame in a case that the coding mode of the i th video frame is a fixed-bit-rate coding mode.

3. The method according to claim 2 , wherein the calculating comprises:
calculating, in a case that an (i−1) th video frame is an I frame and the (i−1) th video frame is encoded at the second coding resolution, an average value of actual quantization parameters of all coding blocks in the (i−1) th video frame, obtaining a first offset and a second offset, determining a sum of the average value, the first offset and the second offset as the quantization parameter of the first coding block;
calculating, in a case that an (i−1) th video frame is an I frame and the (i−1) th video frame is encoded at the first coding resolution, the average value of actual quantization parameters of all coding blocks in the (i−1) th video frame, obtaining the second offset, and determining a sum of the average value and the second offset as the quantization parameter of the first coding block;
calculating, in a case that an (i−1) th video frame is a P frame and the (i−1) th video frame is encoded at the first coding resolution, the average value of actual quantization parameters of all coding blocks in the (i−1) th video frame, and determining the average value as the quantization parameter of the first coding block; and
calculating, in a case that an (i−1) th video frame is a P frame and the (i−1) th video frame is encoded at the second coding resolution, the average value of actual quantization parameters of all coding blocks in the (i−1) th video frame, obtaining the first offset, and determining a sum of the average value and the first offset as the quantization parameter of the first coding block,
wherein the first offset is an offset between a quantization parameter corresponding to the first coding resolution and a quantization parameter corresponding to the second coding resolution, and the second offset is an offset between quantization parameters of the I frame and the P frame.

4. The method according to claim 1 , wherein the calculating comprises:
dividing the first coding cost by the second coding cost to obtain a coding cost ratio; and
determining the quantization parameter threshold according to the coding cost ratio, the coding cost ratio being in a positive correlation with the quantization parameter threshold.

5. The method according to claim 4 , wherein the calculating the first coding cost comprises:
dividing the i th video frame into at least two coding blocks;
performing intra-frame prediction coding on the coding blocks to obtain intra-frame coding costs; and
determining a sum of the intra-frame coding costs as the first coding cost.

6. The method according to claim 4 , wherein the calculating the second coding cost comprises:
dividing the i th video frame into at least two coding blocks;
performing inter-frame prediction coding on the coding blocks to obtain inter-frame coding costs; and
determining a sum of the inter-frame coding costs as the second coding cost.

7. The method according to claim 1 , wherein the determining the quantization threshold parameter according to the coding cost ratio, the two threshold sets and the first coding resolution comprises:
searching for a threshold set corresponding to the first coding resolution in the two threshold sets; and
searching for the quantization threshold parameter in the threshold set according to the coding cost ratio.

8. The method according to claim 1 , wherein the determining the quantization threshold parameter according to the coding cost ratio, the two threshold sets and the second coding resolution comprises:
searching for a threshold set corresponding to the second coding resolution in the two threshold sets; and
searching for the quantization threshold parameter in the threshold set according to the coding cost ratio.

9. The method according to claim 1 , wherein the determining comprises:
determining that the coding resolution of the i th video frame is the first coding resolution in a case that the quantization parameter is less than or equal to the quantization parameter threshold; and
determining that the coding resolution of the video frame is the second coding resolution in a case that the quantization parameter is greater than the quantization parameter threshold.

10. The method according to claim 9 , wherein, in a case that there is one threshold set and the threshold set corresponds to the first coding resolution, before the determining a coding resolution of the video frame according to the quantization parameter and the quantization parameter threshold, the method further comprises:
determining the quantization parameter as a final quantization parameter in a case that the coding resolution of the i th video frame is assumed to be the first coding resolution during calculation of the quantization parameter; and
adding a first offset to the quantization parameter to obtain the final quantization parameter in a case that the coding resolution of the i th video frame is assumed to be the second coding resolution during calculation of the quantization parameter.

11. The method according to claim 9 , wherein, in a case that there is one threshold set and the threshold set corresponds to the secon

Assignees

• Tencent Tech Shenzhen Co Ltd

Inventors

• Mao Xunan
• Guo Licai
• Shi Yongfang
• Gao Anlin
• Gao Xinwei
• Zhang Tao
• Deng Haibo
• Gu Chenchen
• Lv Jing

Classifications

• H04N19/33

  in the spatial domain · CPC title

• H04N21/4788

  communicating with other users, e.g. chatting {(arrangements for providing for computer conferences, e.g. chat rooms, to substation in data switching networks H04L12/1813; distributed application using peer-to-peer [P2P] networks H04L67/104)} · CPC title

• H04N19/147

  according to rate distortion criteria (rate-distortion as a criterion for motion estimation H04N19/567) · CPC title

• H04N19/154

  Measured or subjectively estimated visual quality after decoding, e.g. measurement of distortion (use of rate-distortion criteria H04N19/147) · CPC title

• H04N19/115

  Selection of the code volume for a coding unit prior to coding · CPC title