Transformation mode encoding and decoding method and apparatus

A transformation mode encoding method, comprising:

• obtaining a prediction mode of a predicted data block that corresponds to a residual data block of a video image to be encoded;
• determining a simplified candidate transformation mode set according to the prediction mode and a correspondence between a candidate transformation mode set and the prediction mode;
• selecting a transformation mode from the simplified candidate transformation mode set, wherein the transformation mode is used to minimize distortion of the video image and a reconstructed video image that is obtained by a decoding end and to minimize a quantity of encoding bits required for encoding the video image;
• performing a transformation operation on the residual data block of the video image based on the optimal transformation mode;
• and
• encoding an index of the optimal transformation mode in a code stream.

A transformation mode encoding method, comprising:

• obtaining a prediction mode of a predicted data block that corresponds to a residual data block of a video image to be encoded;
• selecting a transformation mode from a candidate transformation mode set, wherein the transformation mode is used to minimize distortion of the video image and a reconstructed video image that is obtained by a decoding end and to minimize a quantity of encoding bits required for the video image;
• determining whether the optimal transformation mode is a mode having a correspondence with the prediction mode;
• writing a determination result in a code stream;
• if the optimal transformation mode is not a mode having a correspondence with the prediction mode, then encoding an index of the optimal transformation mode in the code stream;
• and
• performing a transformation operation on the residual data block of the video image based on the optimal transformation mode.

A transformation mode decoding method, comprising:

• obtaining a prediction mode of a predicted data block that corresponds to a transformation coefficient block of an image to be decoded;
• selecting a transformation mode corresponding to the prediction mode from a candidate transformation mode set;
• and
• performing an inverse transformation operation on the transformation coefficient block of the image based on the transformation mode.

A transformation mode decoding method, comprising:

• obtaining a prediction mode of a predicted data block that corresponds to a transformation coefficient block of an image to be decoded;
• determining a simplified candidate transformation mode set according to the prediction mode and a correspondence between a candidate transformation mode set and the prediction mode;
• parsing a code stream to obtain an index of an optimal transformation mode;
• and
• performing an inverse transformation operation on the transformation coefficient block of the image based on the optimal transformation mode corresponding to the index.

A transformation mode decoding method, comprising:

• obtaining a prediction mode of a predicted data block that corresponds to a transformation coefficient block of an image to be decoded;
• parsing a code stream to obtain a determination result about whether an optimal transformation mode is a mode having a correspondence with the prediction mode;
• if the determination result is no, parsing the code stream to obtain an index of the optimal transformation mode;
• and
• performing an inverse transformation operation on the transformation coefficient block of the image based on the optimal transformation mode corresponding to the index.

A transformation mode encoding apparatus, comprising:

• a first obtaining unit, configured to obtain a prediction mode of a predicted data block that corresponds to a residual data block of a video image to be encoded;
• a first selecting unit, configured to select a transformation mode corresponding to the prediction mode from a candidate transformation mode set;
• and
• a first processing unit, configured to perform a transformation operation on the residual data block of the video image based on the transformation mode.

A transformation mode encoding apparatus, comprising:

• a second obtaining unit, configured to obtain a prediction mode of a predicted data block that corresponds to a residual data block of a video image to be encoded;
• a second determining unit, configured to determine a simplified candidate transformation mode set according to the prediction mode and a correspondence between a candidate transformation mode set and the prediction mode;
• a second selecting unit, configured to select a transformation mode from the simplified candidate transformation mode set, wherein the transformation mode is used to minimize distortion of the video image and a reconstructed video image that is obtained by a decoding end and minimize a quantity of encoding bits required for encoding the video image;
• a second encoding unit, configured to encode an index of the transformation mode in a code stream;
• and
• a second processing unit, configured to perform a transformation operation on the residual data block of the video image based on the transformation mode.

A transformation mode encoding apparatus, comprising:

• a third obtaining unit, configured to obtain a prediction mode of a predicted data block that corresponds to a residual data block of a video image to be encoded;
• a third selecting unit, configured to select a transformation mode from a candidate transformation mode set, wherein the transformation mode is used to minimize distortion of the video image and a reconstructed video image that is obtained by a decoding end and minimize a quantity of encoding bits required for encoding the video image;
• a third determining unit, configured to determine whether the transformation mode is a mode having a correspondence with the prediction mode;
• a third encoding unit, configured to encode the determination result and an index of the transformation mode in a code stream;
• and
• a third processing unit, configured to perform a transformation operation on the residual data block of the video image based on the transformation mode.

A transformation mode decoding apparatus, comprising:

• a fourth obtaining unit, configured to obtain a prediction mode of a predicted data block that corresponds to a transformation coefficient block of an image to be decoded;
• a fourth selecting unit, configured to select a transformation mode corresponding to the prediction mode from a candidate transformation mode set;
• and
• a fourth processing unit, configured to perform an inverse transformation operation on the transformation coefficient block of the image based on the transformation mode.

A transformation mode decoding apparatus, comprising:

• a fifth obtaining unit, configured to obtain a prediction mode of a predicted data block that corresponds to a transformation coefficient block of an image to be decoded;
• a fifth determining unit, configured to determine a simplified candidate transformation mode set according to the prediction mode and a correspondence between a candidate transformation mode set and the prediction mode;
• a fifth decoding unit, configured to parse a code stream to obtain an index of an optimal transformation mode;
• and
• a fifth processing unit, configured to perform an inverse transformation operation on the transformation coefficient block of the image based on the transformation mode.

A transformation mode decoding apparatus, comprising:

• a sixth obtaining unit, configured to obtain a prediction mode of a predicted data block that corresponds to a transformation coefficient block of an image to be decoded;
• a sixth determining unit, configured to determine, in a candidate transformation mode set, a transformation mode corresponding to the prediction mode;
• and
• a sixth decoding unit, configured to parse a code stream to obtain a determination result about whether an optimal transformation mode is a mode having a correspondence with the prediction mode, and an index of the optimal transformation mode;
• and
• a sixth processing unit, configured to perform an inverse transformation operation on the transformation coefficient block of the image based on the transformation mode.