Method and apparatus for signaling image information, and decoding method and apparatus using same
The present invention relates to a method for signaling image information and to a decoding method using same. The method for signaling image information according to the present invention comprises: a step of performing inter-prediction for a current picture; and a step of signaling information including the result of said inter-prediction and reference picture information indicating reference pictures usable in said inter prediction, wherein said reference picture information contains pieces of picture order count (POC) information of said usable reference pictures. The POC information of said usable reference pictures in said reference picture information is configured such that POCs for the pictures existing before said current picture in terms of a POC sequence are located at the front, and POCs for the pictures existing after said current picture in terms of a POC sequence are located following the POCs located at the front.
1. A video decoding method performed by a decoding apparatus, the method comprising:
receiving picture order count (POC) information;
deriving POC values of the reference pictures based on the POC information;
constructing a reference picture list based on the POC values of the reference pictures, and
performing an inter prediction on a current block based on the reference picture list to derive a predicted sample of the current block,
wherein a POC value of an i-th reference picture is derived based on a POC difference derived from the POC information,
wherein 0-th reference picture is an initial reference picture,
wherein the POC difference specifies a difference between the POC values of the current picture and the i-th reference picture based on the i-th reference picture being a firstly-ordered reference picture specified by the POC information, and
wherein the POC difference specifies a difference between the POC values of the i-th reference picture and an (i−1)-th reference picture based on the i-th reference picture being a secondly-ordered reference picture or a subsequent reference picture specified by the POC information.
2. The method of claim 1 , wherein deriving the POC values includes
deriving POC differences for the reference pictures previous to the current picture in the POC order, in the descending order of the POC order, and
deriving the POC differences for the reference pictures subsequent to the current picture in the POC order, in the ascending order of the POC order.
3. The method of claim 1 , wherein POC differences for the reference pictures previous to the current picture in the POC order have a negative sign, and
wherein POC differences for the reference pictures subsequent to the current picture in the POC order have a positive sign.
4. A video encoding method performed by an encoding apparatus, the method comprising:
deriving POC values of the reference pictures which are used for inter prediction of a current picture;
deriving POC information of the reference pictures, wherein the POC information is related to POC differences for the reference pictures based on the derived POC values; and
encoding video information including the POC information,
wherein 0-th reference picture is an initial reference picture,
wherein the POC difference specifies a difference between the POC values of the current picture and the i-th reference picture based on the i-th reference picture being a firstly-ordered reference picture specified by the POC information, and
wherein the POC difference specifies a difference between the POC values of the i-th reference picture and an (i−1)-th reference picture based on the i-th reference picture being a secondly-ordered reference picture or a subsequent reference picture specified by the POC information.
5. The method of claim 4 , wherein deriving the POC values includes
deriving POC differences for the reference pictures previous to the current picture in the POC order, in the descending order of the POC order, and
deriving the POC differences for the reference pictures subsequent to the current picture in the POC order, in the ascending order of the POC order.
6. The method of claim 4 , wherein POC differences for the reference pictures previous to the current picture in the POC order have a negative sign, and
wherein POC differences for the reference pictures subsequent to the current picture in the POC order have a positive sign.
7. A non-transitory decoder-readable storage medium storing the encoded video information generated by a video encoding method, the method comprising: deriving POC values of the reference pictures which are used for inter prediction of a current picture; deriving POC information of the reference pictures, wherein the POC information is related to POC differences for the reference pictures based on the derived POC values; and encoding video information including the POC information, wherein 0-th reference picture is an initial reference picture, wherein the POC difference specifies a difference between the POC values of the current picture and the i-th reference picture based on the i-th reference picture being a firstly-ordered reference picture specified by the POC information, and wherein the POC difference specifies a difference between the POC values of the i-th reference picture and an (i−1)-th reference picture based on the i-th reference picture being a secondly-ordered reference picture or a subsequent reference picture specified by the POC information.