Video encoding method and device and decoding method and device

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.

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.

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.

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.

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.

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.

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 and includes elements that are integers.

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 and includes elements that are integers,
• the prediction information indicates an intra mode or an inter mode.