VIDEO ENCODING METHOD AND DEVICE AND DECODING METHOD AND DEVICE

• US 20180310026A1
• Filed: 07/02/2018
• Published: 10/25/2018
• Est. Priority Date: 09/28/2010
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: HONG, Yoon-Mi, HAN, Woo-Jin, CHEON, Min-Su, CHEN, Jianle
• Granted Patent: US 10,455,252 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 17/147 Discrete orthonormal transforms, e.g. discrete cosine transform, discrete sine transform, and variations therefrom, e.g. modified discrete cosine transform, integer transforms approximating the discrete cosine transform G06F17/145 takes precedence
• 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 19/60 using transform coding
• CPC Class Codes: H04N 19/625 using discrete cosine transform [DCT]

Abstract

A video encoding method, a video encoding apparatus, a video decoding method, and a video decoding apparatus are provided. The video encoding method includes producing a fast transform matrix based on a transform matrix which is used for frequency transformation on a block which has a predetermined size; producing a transformed block by transforming the block having the predetermined size by using the fast transform matrix; and performing scaling with respect to the transformed block in order to correct a difference between the transform matrix used for the frequency transformation and the fast transform matrix.

Claims

1. A video decoding apparatus comprising a processor configured to:

receive a quantized transform block which has a predetermined size,

determine a scaling constant for scaling of transform coefficients included in the quantized transform block based on a quantization parameter,

scale the transform coefficients by using the scaling constant, and

inverse-transform the transform block that includes the scaled transform coefficients,

wherein, where i denotes a remainder after the quantization parameter is divided by 6, the scaling constant for i=0 is 40, the scaling constant for i=1 is 45, the scaling constant for i=2 is 51, the scaling constant for i=3 is 57, the scaling constant for i=4 is 64, and the scaling constant for i=5 is 72, and

the transform block is inverse-transformed by using discrete cosine inverse-transform or discrete sine inverse-transform.

2. A video encoding apparatus comprising a processor configured to:

obtain a transform block by transforming a residual block indicating differences between a current block and a predicted block of the current block,

determine a scaling constant for quantization of transform coefficients included in the transform block based on a quantization parameter,

quantize the transform coefficients in the transform block based on the scaling constant,

entropy-code the quantized transform block, and

output a bitstream including quantized transform block information indicating the quantized transform block,

wherein, where i denotes a remainder after the quantization parameter is divided by 6, the scaling constant for i=0 is 40, the scaling constant for i=1 is 45, the scaling constant for i=2 is 51, the scaling constant for i=3 is 57, the scaling constant for i=4 is 64, and the scaling constant for i=5 is 72.

3. A video encoding method comprising:

obtaining a transform block by transforming a residual block indicating differences between a current block and a predicted block of the current block;

determining a scaling constant for quantization of transform coefficients included in the transform block based on a quantization parameter;

quantizing the transform coefficients in the transform block based on the scaling constant;

entropy-coding the quantized transform block; and

output a bitstream including quantized transform block information indicating the quantized transform block,

wherein, where i denotes a remainder after the quantization parameter is divided by 6, the scaling constant for i=0 is 40, the scaling constant for i=1 is 45, the scaling constant for i=2 is 51, the scaling constant for i=3 is 57, the scaling constant for i=4 is 64, and the scaling constant for i=5 is 72, and

the transform block is transformed by using discrete cosine transform or discrete sine transform.

4. A video encoding apparatus comprising a processor configured to:

obtain a transform block by transforming a residual block indicating differences between a current block and a predicted block of the current block,

determine a scaling constant for quantization of transform coefficients included in the transform block based on a quantization parameter,

quantize the transform coefficients in the transform block based on the scaling constant,

entropy-code the quantized transform block, and

output a bitstream including quantized transform block information indicating the quantized transform block,

wherein, where i denotes a remainder after the quantization parameter is divided by 6, the scaling constant for i=0 is 40, the scaling constant for i=1 is 45, the scaling constant for i=2 is 51, the scaling constant for i=3 is 57, the scaling constant for i=4 is 64, and the scaling constant for i=5 is 72, and

the transform block is transformed by using discrete cosine transform or discrete sine inverse-transform.

5. A video encoding method comprising:

obtaining a transform block by transforming a residual block indicating differences between a current block and a predicted block of the current block;

determining a scaling constant for quantization of transform coefficients included in the transform block based on a quantization parameter;

quantizing the transform coefficients in the transform block based on the scaling constant;

entropy-coding the quantized transform block; and

output a bitstream including quantized transform block information indicating the quantized transform block,

wherein, where i denotes a remainder after the quantization parameter is divided by 6, the scaling constant for i=0 is 40, the scaling constant for i=1 is 45, the scaling constant for i=2 is 51, the scaling constant for i=3 is 57, the scaling constant for i=4 is 64, and the scaling constant for i=5 is 72, and

a transform matrix includes elements that are integers.

6. A non-transitory computer-readable recording medium comprising a bitstream, the bitstream comprising:

quantized transform block information indicating a quantized transform block of a current block;

quantization parameter information indicating a quantization parameter; and

prediction mode information indicating a prediction mode of the current block.

wherein,

the quantized transform block is derived by entropy-decoding the quantized transform block information,

transform coefficients in the quantized transform block are scaled by using a scaling constant that is determined based on the quantization parameter,

a transform block that includes the scaled transform coefficients is inverse-transformed to obtain a residual block indicating differences between the current block and a predicted block of the current block,

the predicted block of the current block is determined based on the prediction mode of the current block,

wherein, where i denotes a remainder after the quantization parameter is divided by 6, the scaling constant for i=0 is 40, the scaling constant for i=1 is 45, the scaling constant for i=2 is 51, the scaling constant for i=3 is 57, the scaling constant for i=4 is 64, and the scaling constant for i=5 is 72, and

the transform block is transformed by using discrete cosine transform or discrete sine transform.

7. A non-transitory computer-readable recording medium comprising a bitstream, the bitstream comprising:

quantized transform block information indicating a quantized transform block of a current block;

quantization parameter information indicating a quantization parameter; and

prediction mode information indicating a prediction mode of the current block.

wherein,

the quantized transform block is derived by entropy-decoding the quantized transform block information,

transform coefficients in the quantized transform block are scaled by using a scaling constant that is determined based on the quantization parameter,

a transform block that includes the scaled transform coefficients is inverse-transformed to obtain a residual block indicating differences between the current block and a predicted block of the current block,

the predicted block of the current block is determined based on the prediction mode of the current block,

wherein, where i denotes a remainder after the quantization parameter is divided by 6, the scaling constant for i=0 is 40, the scaling constant for i=1 is 45, the scaling constant for i=2 is 51, the scaling constant for i=3 is 57, the scaling constant for i=4 is 64, and the scaling constant for i=5 is 72, and

the transform matrix includes elements that are integers.

8. A non-transitory computer-readable recording medium comprising a bitstream, the bitstream comprising:

quantized transform block information indicating a quantized transform block of a current block;

quantization parameter information indicating a quantization parameter; and

prediction mode information indicating a prediction mode of the current block.

wherein,

the quantized transform block is derived by entropy-decoding the quantized transform block information,

transform coefficients in the quantized transform block are scaled by using a scaling constant that is determined based on the quantization parameter,

a transform block that includes the scaled transform coefficients is inverse-transformed to obtain a residual block indicating differences between the current block and a predicted block of the current block,

the predicted block of the current block is determined based on the prediction mode of the current block,

wherein, where i denotes a remainder after the quantization parameter is divided by 6, the scaling constant for i=0 is 40, the scaling constant for i=1 is 45, the scaling constant for i=2 is 51, the scaling constant for i=3 is 57, the scaling constant for i=4 is 64, and the scaling constant for i=5 is 72,

the transform block is transformed by using discrete cosine transform or discrete sine transform and includes elements that are integers.

9. A non-transitory computer-readable recording medium comprising a bitstream, the bitstream comprising:

quantized transform block information indicating a quantized transform block of a current block;

quantization parameter information indicating a quantization parameter; and

prediction mode information indicating a prediction mode of the current block.

wherein,

the quantized transform block is derived by entropy-decoding the quantized transform block information,

transform coefficients in the quantized transform block are scaled by using a scaling constant that is determined based on the quantization parameter,

a transform block that includes the scaled transform coefficients is inverse-transformed to obtain a residual block indicating differences between the current block and a predicted block of the current block,

the predicted block of the current block is determined based on the prediction mode of the current block,

wherein, where i denotes a remainder after the quantization parameter is divided by 6, the scaling constant for i=0 is 40, the scaling constant for i=1 is 45, the scaling constant for i=2 is 51, the scaling constant for i=3 is 57, the scaling constant for i=4 is 64, and the scaling constant for i=5 is 72,

the transform block is transformed by using discrete cosine transform or discrete sine transform and includes elements that are integers,

the prediction information indicates an intra mode or an inter mode.