Image encoding method, decoding method, encoder, and decoder

An image decoding method, comprising:

• parsing a bitstream to obtain a prediction difference parameter, a filtering parameter and an intra prediction mode of a decoding block;
• wherein the filtering parameter is determined according to an original value of an encoding block and a first prediction value of the encoding block constructed according to an intra prediction mode of the encoding block, and the filtering parameter comprises a filtering indication parameter and a filter parameter for indicating a filter coefficient of a filter in use;
• constructing a first prediction value of the decoding block according to the intra prediction mode of the decoding block;
• wherein the first prediction value is determined by using unfiltered restored pixels adjacent to the encoding block in an image in which the encoding block is located
• in a case where the filtering indication parameter indicates performing filtering processing on the first prediction value of the decoding block, performing the filtering processing on the first prediction value of the decoding block to obtain an intra prediction value;
• calculating a prediction difference of the decoding block according to the prediction difference parameter;
• calculating a sum of the intra prediction value and the prediction difference to obtain a first decoding value of the decoding block;
• and
• obtaining a decoding restored value of the decoding block according to the first decoding value;
• wherein the filtering indication parameter comprises at least one of:
• a sequence layer filtering control parameter;
• wherein the sequence layer filtering control parameter comprises at least one of:
• at least one flag bit for indicating whether the filtering processing is required to be performed on a first prediction value of an encoding block which is in a video sequence and uses the intra prediction mode;
• at least one first preset value of a size of an encoding block;
• wherein the at least one first preset value indicates that the filtering processing is required to be performed on a first prediction value of an encoding block which is in a video sequence and has a size equal to each of the at least one first preset value;
• or
• at least one second preset value of an intra prediction mode;
• wherein the at least one second preset value indicates that the filtering processing is required to be performed on a first prediction value of an encoding block which is in a video sequence and uses an intra prediction mode indicated by each of the at least one second preset value;
• an image layer filtering control parameter;
• wherein the image layer filtering control parameter comprises at least one of:
• at least one flag bit for indicating whether the filtering processing is required to be performed on a first prediction value of an encoding block which is in the image and uses the intra prediction mode;
• at least one third preset value of a size of an encoding block;
• wherein the at least one third preset value indicates that the filtering processing is required to be performed on a first prediction value of an encoding block which is in the image and has a size equal to each of the at least one third preset value;
• or
• at least one fourth preset value of an intra prediction mode;
• wherein the at least one fourth preset value indicates that the filtering processing is required to be performed on a first prediction value of an encoding block which is in the image and uses an intra prediction mode indicated by each of the at least one fourth preset value;
• a slice layer filtering control parameter;
• the slice layer filtering control parameter comprises at least one of:
• at least one flag bit for indicating whether the filtering processing is required to be performed on a first prediction value of an encoding block which is in a slice and uses the intra prediction mode;
• at least one fifth preset value of a size of an encoding block;
• wherein the at least one fifth preset value indicates that the filtering processing is required to be performed on a first prediction value of an encoding block which is in a slice and has a size equal to each of the at least one fifth preset value;
• or
• at least one sixth preset value of an intra prediction mode;
• wherein the at least one sixth preset value indicates that the filtering processing is required to be performed on a first prediction value of an encoding block which is in a slice and uses an intra prediction mode indicated by each of the at least one sixth preset value;
• or
• a block layer filtering control parameter;
• wherein the block layer filtering control parameter comprises at least one of:
• at least one flag bit for indicating whether the filtering processing is required to be performed on the first prediction value of the encoding block;
• at least one seventh preset value of a size of an encoding block, used for indicating that the filtering processing is performed on the first prediction value of the encoding block in a case where a size of the encoding block is equal to the at least one seventh preset value;
• or
• at least one eighth preset value of an intra prediction mode, used for indicating that the filtering processing is performed on the first prediction value of the encoding block in a case where the intra prediction mode of the encoding block is same as an intra prediction mode indicated by each of the at least one eighth preset value.

An encoder, comprising:

• a first processor, a first storage medium, and a first communication bus;
• wherein the first processor is connected to the first storage medium through the first communication bus;
• and the first processor calls an image encoding-related program stored in the first storage medium and performs the following steps:
• determining an intra prediction mode of an encoding block, and constructing a first prediction value of the encoding block according to the intra prediction mode;
• determining, by using a rate-distortion optimization method, a filtering parameter according to the first prediction value and an original value of the encoding block;
• wherein the filtering parameter comprises a filtering indication parameter and a filter parameter for indicating a filter coefficient of a filter in use, wherein the first prediction value is determined by using unfiltered restored pixels adjacent to the encoding block in an image in which the encoding block is located;
• in a case where the filtering indication parameter indicates performing filtering processing on the first prediction value, performing the filtering processing on the first prediction value to obtain an intra prediction value;
• calculating a prediction difference parameter according to a difference between the original value of the encoding block and the intra prediction value;
• and
• encoding the intra prediction mode, the filtering parameter, and the prediction difference parameter, and writing encoded bits into a bitstream;
• wherein the filtering indication parameter comprises at least one of:
• a sequence layer filtering control parameter, wherein the sequence layer filtering control parameter comprises at least one of:
• at least one flag bit for indicating whether the filtering processing is required to be performed on a first prediction value of an encoding block which is in a video sequence and uses the intra prediction mode;
• at least one first preset value of a size of an encoding block;
• wherein the at least one first preset value indicates that the filtering processing is required to be performed on a first prediction value of an encoding block which is in a video sequence and has a size equal to each of the at least one first preset value;
• or
• at least one second preset value of an intra prediction mode;
• wherein the at least one second preset value indicates that the filtering processing is required to be performed on a first prediction value of an encoding block which is in a video sequence and uses an intra prediction mode indicated by each of the at least one second preset value;
• an image layer filtering control parameter;
• wherein the image layer filtering control parameter comprises at least one of:
• at least one flag bit for indicating whether the filtering processing is required to be performed on a first prediction value of an encoding block which is in the image and uses the intra prediction mode;
• at least one third preset value of a size of an encoding block;
• wherein the at least one third preset value indicates that the filtering processing is required to be performed on a first prediction value of an encoding block which is in the image and has a size equal to each of the at least one third preset value;
• or
• at least one fourth preset value of an intra prediction mode;
• wherein the at least one fourth preset value indicates that the filtering processing is required to be performed on a first prediction value of an encoding block which is in the image and uses an intra prediction mode indicated by each of the at least one fourth preset value;
• a slice layer filtering control parameter;
• the slice layer filtering control parameter comprises at least one of:
• at least one flag bit for indicating whether the filtering processing is required to be performed on a first prediction value of an encoding block which is in a slice and uses the intra prediction mode;
• at least one fifth preset value of a size of an encoding block;
• wherein the at least one fifth preset value indicates that the filtering processing is required to be performed on a first prediction value of an encoding block which is in a slice and has a size equal to each of the at least one fifth preset value;
• or
• at least one sixth preset value of an intra prediction mode;
• wherein the at least one sixth preset value indicates that the filtering processing is required to be performed on a first prediction value of an encoding block which is in a slice and uses an intra prediction mode indicated by each of the at least one sixth preset value;
• or
• a block layer filtering control parameter;
• wherein the block layer filtering control parameter comprises at least one of:
• at least one flag bit for indicating whether the filtering processing is required to be performed on the first prediction value of the encoding block;
• at least one seventh preset value of a size of an encoding block, used for indicating that the filtering processing is performed on the first prediction value of the encoding block in a case where a size of the encoding block is equal to the at least one seventh preset value;
• or
• at least one eighth preset value of an intra prediction mode, used for indicating that the filtering processing is performed on the first prediction value of the encoding block in a case where the intra prediction mode of the encoding block is same as an intra prediction mode indicated by each of the at least one eighth preset value.