Context-based adaptive arithmetic coding and decoding methods and apparatuses with improved coding efficiency and video coding and decoding methods and apparatuses using the same

A method for performing context-based adaptive arithmetic coding on a given slice in a low-pass frame of a video signal, the method comprising:

• resetting a context model for the given slice to a context model for a slice coded temporally before the given slice;
• arithmetically encoding a data symbol of the given slice using the reset context model;
• and
• updating the context model using a value of the arithmetically encoded data symbol.

A method for performing context-based adaptive arithmetic decoding on a given slice in a high-pass frame of a video signal, the method comprising:

• resetting a context model for the given slice to a context model decoded temporally before the given slice;
• arithmetically decoding a bitstream corresponding to the given slice using the reset context model to generate a data symbol of the given slice;
• and
• updating the context model using a value of the data symbol.

A method for performing context-based adaptive arithmetic decoding on a given slice in a low-pass frame of a video signal, the method comprising:

• resetting a context model for the given slice to a context model for a slice decoded temporally before the given slice;
• arithmetically decoding a bitstream corresponding to the given slice using the reset context model to generate a data symbol of the given slice;
• and
• updating the context model using a value of the data symbol.

A video coding method comprising a method for performing context-based adaptive arithmetic coding on a given slice in a high-pass frame in a temporal level in a temporally filtered hierarchical structure, the video coding method comprising:

• subtracting a predicted image for a block in the given slice from the block and generating a residual;
• performing spatial transform on the residual to create a transform coefficient;
• quantizing the transform coefficient;
• resetting a context model for the given slice to a context model for a slice coded temporally before the given slice;
• arithmetically encoding a data symbol comprising the quantized transform coefficient using the reset context model to generate a bitstream;
• updating the context model using a value of the arithmetically encoded data symbol;
• and
• transmitting the bitstream.

A video decoding method including a method for performing context-based adaptive arithmetic decoding on a given slice in a high-pass frame in a temporal level in a temporally filtered hierarchical structure, the video decoding method comprising:

• parsing a bitstream and extracting data about a block in the given slice to be reconstructed;
• resetting a context model for the given slice to a context model for a slice decoded temporally before the given slice;
• arithmetically decoding a bitstream corresponding to the block using the reset context model to generate a data symbol of the given slice;
• updating the context model using a value of the data symbol;
• dequantizing the data symbol to generate a transform coefficient;
• performing inverse spatial transform on the transform coefficient to reconstruct a residual obtained by subtracting a predicted image from the block;
• and
• adding the predicted image reconstructed by motion compensation to the reconstructed residual and reconstructing the block.

A method of context-based adaptive arithmetic coding of a video signal, the method comprising:

• resetting a context model for a given slice to a different context model varying according to a type of a block in the given slice;
• arithmetically encoding a data symbol of the block using the reset context model;
• and
• updating the context model reset according to the type of the block.

A method of context-based adaptive arithmetic decoding of a video signal, the method comprising:

• resetting a context model for a given slice comprising a block to a different context model varying according to a type of the block in the given slice;
• arithmetically decoding a bitstream corresponding to the block using a context model corresponding to the block type to generate a data symbol of the given slice;
• and
• updating the context model according to the block type using a value of the data symbol.

A video coding method comprising:

• subtracting a predicted image for a block from the block and generating a residual;
• performing spatial transform on the residual to create a transform coefficient;
• quantizing the transform coefficient;
• resetting a context model for a given slice comprising the block to a different context model varying according to a type of the block;
• arithmetically encoding a data symbol of the block using a context model reset according to the type of the block to generate a bitstream;
• updating the context model reset according to the type of the block;
• and
• transmitting the bitstream.

A video decoding method comprising:

• parsing a bitstream and extracting data about a block to be reconstructed;
• resetting a context model for a given slice comprising the block to a different context model varying according to a type of the block in the given slice;
• arithmetically decoding a bitstream corresponding to the block using a context model corresponding to the block type to generate a data symbol of the given slice;
• updating the context model according to the block type using a value of the data symbol;
• dequantizing the data symbol to generate a transform coefficient;
• performing inverse spatial transform on the transform coefficient to reconstruct a residual obtained by subtracting a predicted image from the block;
• and
• adding the predicted image reconstructed by motion compensation to the reconstructed residual and reconstructing the block.

A video coding method comprising:

• subtracting a predicted image for a block from the block and generating a residual;
• performing spatial transform on the residual to create a transform coefficient;
• quantizing the transform coefficient;
• resetting a context model for a given slice comprising the block as a predetermined initial value;
• performing context-based adaptive arithmetic coding on a data symbol of the given slice using the context model and generating a final probability model;
• performing another context-based adaptive arithmetic coding on the data symbol of the given slice using information about the final probability model as an initial value to generate a bitstream;
• and
• transmitting the bitstream comprising information about the final probability model.

A video decoding method comprising:

• extracting an initial value of a context model in a given slice comprising a block to be reconstructed from a bitstream;
• resetting a context model for the given slice using the initial value;
• arithmetically decoding a bitstream corresponding to the block using the reset context model to generate a data symbol of the given slice;
• and
• updating the context model using a value of the data symbol;
• dequantizing the data symbol to generate a transform coefficient;
• performing inverse spatial transform on the transform coefficient to reconstruct a residual obtained by subtracting a predicted image from the block;
• and
• adding the predicted image reconstructed by motion compensation to the reconstructed residual and reconstructing the block.

A video encoder for performing context-based adaptive arithmetic coding on a given slice in a high-pass frame in a temporal level in a temporally filtered hierarchical structure, the video encoder comprising:

• a unit which subtracts a predicted image for a block in the given slice from the block and generates a residual;
• a unit which performs spatial transform on the residual to create a transform coefficient;
• a unit which quantizes the transform coefficient;
• a unit which resets a context model for the given slice to a context model for a slice coded temporally before the given slice;
• a unit which arithmetically encodes a data symbol comprising the quantized transform coefficient using the reset context model to generate a bitstream;
• a unit which updates the context model using a value of the arithmetically encoded data symbol;
• and
• a unit which transmits the bitstream.

A video decoder for performing context-based adaptive arithmetic decoding on a given slice in a high-pass frame in a temporal level in a temporally filtered hierarchical structure, the video decoder comprising:

• a unit which parses a bitstream and extracts data about a block to be reconstructed in the given slice;
• a unit which resets a context model for the given slice to a context model for a slice decoded temporally before the given slice;
• a unit which arithmetically decodes a bitstream corresponding to the block using the reset context model to generate a data symbol of the given slice;
• a unit which updates the context model using a value of the data symbol;
• a unit which dequantizes the data symbol to generate a transform coefficient;
• a unit which performs inverse spatial transform on the transform coefficient to reconstruct a residual obtained by subtracting a predicted image from the block;
• and
• a unit which adds the predicted image reconstructed by motion compensation to the reconstructed residual and reconstructs the block.

A video encoder comprising:

• a unit which subtracts a predicted image for a block to be reconstructed from the block and generates a residual;
• a unit which performs spatial transform on the residual to create a transform coefficient;
• a unit which quantizes the transform coefficient;
• a unit which resets a context model for a given slice comprising the block to a different context model varying according to a type of the block;
• a unit which arithmetically encodes a data symbol of the block using a context model reset according to the type of the block to generate a bitstream;
• a unit which updates the context model reset according to the type of the block;
• and
• a unit which transmits the bitstream.

A video decoder comprising:

• a unit which parses a bitstream and extracts data about a block to be reconstructed;
• a unit which resets a context model for a given slice comprising the block to a different context model varying according to a type of the block in the given slice;
• a unit which arithmetically decodes the bitstream corresponding to the block using a context model reset according to the type of the block to generate a data symbol of the given slice;
• a unit which updates the context model reset according to the type of the block using a value of the data symbol;
• a unit which dequantizes the data symbol to generate a transform coefficient;
• a unit which performs inverse spatial transform on the transform coefficient to reconstruct a residual obtained by subtracting a predicted image from the block;
• and
• a unit which adds the predicted image reconstructed by motion compensation to the reconstructed residual and reconstructs the block.

A video encoder comprising:

• a unit which subtracts a predicted image for a block from the block and generates a residual;
• a unit which performs spatial transform on the residual to create a transform coefficient;
• a unit which quantizes the transform coefficient;
• a unit which resets a context model for a given slice comprising the block as a predetermined initial value;
• a unit which performs context-based adaptive arithmetic coding on a data symbol of the given slice using the context model and generates a final probability model;
• a unit which performs another context-based adaptive arithmetic coding on the data symbol of the given slice using information about the final probability model as an initial value to generate a bitstream;
• and
• a unit which transmits the bitstream comprising information about the final probability model.

A video decoder comprising:

• a unit which extracts an initial value of a context model in a given slice comprising a block to be reconstructed from a bitstream;
• a unit which resets a context model for the given slice as the initial value;
• a unit which arithmetically decodes a bitstream corresponding to the block to be reconstructed using the context model to generate a data symbol of the given slice;
• a unit which updates the context model using a value of the data symbol;
• a unit which dequantizes the data symbol to generate a transform coefficient;
• a unit which performs inverse spatial transform on the transform coefficient to reconstruct a residual obtained by subtracting a predicted image from the block;
• and
• a unit which adds the predicted image reconstructed by motion compensation to the reconstructed residual and reconstructs the block.