Method and apparatus for encoding/decoding images
Disclosed are a method and apparatus for encoding/decoding images. The image-decoding method comprises the steps of: receiving a bit stream including information regarding an NAL unit type; and checking whether or not the NAL unit in the bit stream is a reference picture based on said information regarding an NAL unit type and decoding the NAL unit. The information regarding an NAL unit type indicates whether the NAL unit is a reference reading picture or not a reference reading picture.
1. An image decoding method, the method comprising:
receiving, by a decoding apparatus, a bitstream;
acquiring, by the decoding apparatus, information indicating a network abstraction layer (NAL) unit type from the bitstream;
determining, by the decoding apparatus, a NAL unit type of a leading picture as one of NAL unit types, based on the information indicating the NAL unit type, wherein the leading picture precedes an associated random access point picture in output order;
configuring, by the decoding apparatus, a reference picture list to perform inter prediction with regard to a picture which follows the leading picture in decoding order, based on the NAL unit type of the leading picture; and
performing, by the decoding apparatus, the inter prediction on at least one block in the picture based on the reference picture list,
wherein the NAL unit types includes a first NAL unit type representing referenced decodable leading picture and a second NAL unit type representing non-referenced decodable leading picture.
2. The method of claim 1 ,
wherein the NAL unit types further includes a third NAL unit type representing referenced skipped leading picture, and a fourth NAL unit type representing non-reference skipped leading picture, and
wherein if the NAL unit type of the leading picture is the second NAL unit type or the fourth NAL unit type, the leading picture is not configured in the reference picture list.
3. The method of claim 1 ,
wherein the NAL unit types further includes a third NAL unit type representing referenced skipped leading picture, and a fourth NAL unit type representing non-reference skipped leading picture, and
wherein if the NAL unit type of the leading picture is the second NAL unit type or the fourth NAL unit type, the leading picture cannot be used for inter prediction of subsequent pictures of the same temporal layer in the decoding order.
4. The method of claim 3 , wherein in the configuring of the reference picture list, the leading picture of which an NAL unit type is the first NAL unit type and the third NAL unit type is included in the reference picture list, and the leading picture is a picture which follows the random access point picture in the decoding order and precedes the random access point picture in the output order.
5. The method of claim 3 , wherein if the NAL unit type of the leading is the second NAL unit type or the fourth NAL unit type, the leading picture can be used for inter prediction of subsequent pictures of higher temporal layers.
6. The method of claim 1 ,
wherein the random access point picture in which random access occurs is an instantaneous decoding refresh (IDR) picture, and
wherein the NAL unit type of the leading picture is the first NAL unit type of the second NAL unit type.
7. The method of claim 2 ,
wherein the random access point picture in which random access occurs is a clean random access (CRA) picture or a broken link access (BLA) picture, and
wherein if the NAL unit type of the leading picture is the second NAL unit type and the fourth NAL unit type, the leading picture is not output.
8. The method of claim 1 ,
wherein the random access point picture in which random access occurs is an instantaneous decoding refresh (IDR) picture, a clean random access (CRA) picture, or a broken link access (BLA) picture, and
wherein pictures stored in a memory are marked with a non-referenced picture.
9. The method of claim 2 , wherein if random access occurs in the random access point picture and the NAL unit type of the leading picture is the second NAL unit type and the fourth NAL unit type, the leading picture is removable without having an effect on the decoding of other pictures of the same temporal layer.