# US 2019/0174134 A1 · Video encoding method, video decoding method, video encoding apparatus, and video decoding apparatus

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- Number: US 2019/0174134 A1
- Document ID: US20190174134A1
- Status: Published application
- Kind: A1
- Application number: 16/269,964
- Filed: 2019-02-07
- Published: 2019-06-06
- Earliest claimed: 2013-06-05
- Assignees: Sun Patent Trust
- Applicants: Sun Patent Trust
- Inventors: Kengo TERADA; Takahiro NISHI; Hisao SASAI; Satoshi YOSHIKAWA
- Web page: https://patentgrep.com/patent/US20190174134A1

## CPC

- H04N 19/146: Data rate or code amount at the encoder output
- H04N 19/105: Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction
- H04N 19/132: Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking
- H04N 19/154: Measured or subjectively estimated visual quality after decoding, e.g. measurement of distortion (use of rate-distortion criteria H04N19/147)
- H04N 19/156: Availability of hardware or computational resources, e.g. encoding based on power-saving criteria
- H04N 19/184: the unit being bits, e.g. of the compressed video stream
- H04N 19/187: the unit being a scalable video layer
- H04N 19/30: using hierarchical techniques, e.g. scalability (H04N19/63 takes precedence)
- H04N 19/31: in the temporal domain
- H04N 19/577: Motion compensation with bidirectional frame interpolation, i.e. using B-pictures
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

A video encoding method of performing scalable encoding on input video includes: determining a total number of layers of the scalable encoding to be less than or equal to a maximum layer count determined according to a frame rate; and performing the scalable encoding on the input video to generate a bitstream, using the determined total number of layers.

## Claims

### Claim 1

A video encoding method of performing scalable encoding on video, the video encoding method comprising:
determining, for the video, a total number of layers that is less than or equal to a maximum layer count based on a frame rate of the video; and
performing the scalable encoding on pictures included in the video to generate a bitstream, using a layer structure including as many layers as the total number of layers determined,
wherein a picture type of pictures included in a shallowest layer of the layers is I-picture or P-picture, the I-picture being intra-frame prediction picture, the P-picture being forward reference prediction picture.

### Claim 2 (depends on 1)

The video encoding method according to claim 1,
wherein a picture type of pictures included in a layer other than the shallowest layer of the layers is B-picture, the B-picture being bi-directional reference prediction picture.

### Claim 3 (depends on 1)

The video encoding method according to claim 1,
wherein the maximum layer count is less than or equal to four when the frame rate is less than or equal to 60 frames per second (fps).

### Claim 4 (depends on 1)

The video encoding method according to claim 1,
wherein the maximum layer count is five when the frame rate is 120 fps.

### Claim 5 (depends on 1)

The video encoding method according to claim 1, further comprising
determining a picture type of pictures included in the video from the I-picture, the P-picture, or B-picture, to make a display latency picture count less than or equal to a maximum picture count determined according to the frame rate, the display latency picture count being a total number of decoded pictures waiting for being outputted in a video decoding apparatus, the B-picture being bi-directional reference prediction picture,
wherein in the performing, the video is encoded as the pictures each having the picture type determined, and
in the determining of a picture type, the picture type of the pictures is determined from the I-picture, the P-picture, and the B-picture, to make a continuous B-picture count less than or equal to a maximum continuous count determined according to the frame rate, the continuous B-picture count being a total number of continuous bi-directional reference prediction pictures.

### Claim 6 (depends on 5)

The video encoding method according to claim 5,
wherein the maximum picture count, an encoder output latency from when the video is input to a video encoding apparatus to when the bitstream is output, and the frame rate are defined by
Maximum picture count=int(log2(encoder output latency [s]×frame rate [fps])),
the maximum continuous count, the encoder output latency, and the frame rate are defined by
Maximum continuous count=int(encoder output latency [s]×frame rate [fps]−1), and
the maximum layer count, the encoder output latency, and the frame rate are defined by
Maximum layer count=int(log2(encoder output latency [s]×frame rate [fps]))+1.

### Claim 7 (depends on 6)

The video encoding method according to claim 6,
wherein a maximum picture count [i] in each layer, the encoder output latency, and the frame rate are defined by
Maximum picture count [i]=int(log2(encoder output latency [s]×frame rate [fps]/2(n-i))), and
a maximum continuous count [i] in each layer, the encoder output latency, and the frame rate are defined by
Maximum continuous count [i]=int(encoder output latency [s]×frame rate [fps]/2(n-i)−1)
where i is an integer less than or equal to the maximum layer count and represents a layer, and n represents (the maximum layer count −1).

### Claim 8

A video decoding method of decoding a bitstream obtained by performing scalable encoding on pictures included in video using a layer structure including as many layers as a total number of layers, the video decoding method comprising:
decoding the pictures in the bitstream;
decoding first information in the bitstream, the first information indicating the total number of layers; and
reordering, using the total number of layers indicated in the first information, the pictures included in the video decoded, and outputting the pictures reordered,
wherein the total number of layers is less than or equal to a maximum layer count predetermined according to a frame rate of the bitstream of the video, and
a picture type of pictures included in a shallowest layer of the layers is I-picture or P-picture, the I-picture being intra-frame prediction picture, the P-picture being forward reference prediction picture.

### Claim 9 (depends on 8)

The video decoding method according to claim 8,
wherein a picture type of a picture included in a layer other than the shallowest layer of the layers is B-picture, the B-picture being bi-directional reference prediction picture.

### Claim 10 (depends on 8)

The video decoding method according to claim 8,
wherein the maximum layer count is less than or equal to four when the frame rate is less than or equal to 60 fps.

### Claim 11 (depends on 8)

The video decoding method according to claim 8,
wherein the maximum layer count is five when the frame rate is 120 fps.

### Claim 12 (depends on 8)

The video decoding method according to claim 8,
wherein further in the decoding of first information, second information in the bitstream is decoded, the second information indicating a display latency picture count which is a total number of decoded pictures waiting for being outputted in a video decoding apparatus, and
in the reordering, the pictures included in the video decoded are reordered using the total number of layers indicated in the first information and the display latency picture count indicated in the second information, and the pictures reordered are output.

### Claim 13 (depends on 12)

The video decoding method according to claim 12,
wherein further in the decoding of first information, third information in the bitstream is decoded, the third information indicating a continuous B-picture count which is a total number of continuous bi-directional prediction pictures, and
in the reordering, the pictures included in the video decoded are reordered using the total number of layers indicated in the first information, the display latency picture count indicated in the second information, and the continuous B-picture count indicated in the third information, and the pictures reordered are output.

### Claim 14 (depends on 13)

The video decoding method according to claim 13,
wherein a maximum picture count determined according to the frame rate, an encoder output latency from when the video is input to a video encoding apparatus to when the bitstream is output, and the frame rate are defined by
Maximum picture count=int(log2(encoder output latency [s]×frame rate [fps])),
a maximum continuous count determined according to the frame rate, the encoder output latency, and the frame rate are defined by
Maximum continuous count=int(encoder output latency [s] ×frame rate [fps]−1), and
the maximum layer count, the encoder output latency, and the frame rate are defined by
Maximum layer count=int(log2(encoder output latency [s]×frame rate [fps]))+1.

### Claim 15 (depends on 14)

The video decoding method according to claim 14,
wherein a maximum picture count [i] in each layer, the encoder output latency, and the frame rate are defined by
Maximum picture count [i]=int(log2(encoder output latency [s]×frame rate [fps]/2(n-i))), and
a maximum continuous count [i] in each layer, the encoder output latency, and the frame rate are defined by
Maximum continuous count [i]=int(encoder output latency [s]×frame rate [fps]/2(n-i)−1)
where i is an integer less than or equal to the maximum layer count and represents a layer, and n represents (the maximum layer count −1).

### Claim 16 (depends on 1)

A video encoding apparatus that encodes video, the video encoding apparatus comprising:
processing circuitry; and
storage accessible from the processing circuitry,
wherein using the storage, the processing circuitry performs the video encoding method according to claim 1.

### Claim 17 (depends on 8)

A video decoding apparatus that decodes a bitstream obtained by encoding video, the video decoding apparatus comprising:
processing circuitry; and
storage accessible from the processing circuitry,
wherein using the storage, the processing circuitry performs the video decoding method according to claim 8.