Video-encoding method, video-decoding method, and apparatus implementing same
The present invention relates to an inter-layer prediction method and to an apparatus implementing the method. The method may comprise the steps of generating a first block constituted by the value obtained by up-sampling the reconstruction value of a reference block of a reference layer corresponding to the current block; generating a second block constituted by a prediction value derived from intra-prediction mode of the current block; and generating a prediction block of the current block by combining sample values of the first block and the second block. Thus, intra-prediction on the current layer can be performed using the intra-prediction mode information of another layer.
1. A video decoding method comprising:
receiving a bitstream comprising information on a random access point picture, leading pictures, and normal pictures, wherein the leading pictures precede the random access point picture in output order and the normal pictures follow the random access point picture in output order;
decoding the random access point picture;
decoding at least one of the leading pictures or the normal pictures; and
outputting the decoded random access point picture and the normal pictures,
wherein the random access point picture is a clean random access (CRA) picture or an instantaneous decoding refresh (IDR) picture,
wherein the leading pictures are not used as reference pictures of the normal pictures,
wherein a leading picture associated with the CRA picture is not output if the random access point picture is the CRA picture and a random access happens to the CRA picture, and
wherein a leading picture associated with the IDR picture is decoded by using at least one of the IDR picture or another leading picture as a reference picture if the random access point picture is the IDR picture and the random access happens to the IDR picture.
2. The video decoding method of claim 1 , wherein the leading picture associated with the CRA picture is discarded from the bitstream when the random access point picture is the CRA picture and the random access happens to the CRA picture.
3. The video decoding method of claim 1 , wherein the leading picture associated with the CRA picture contains references to pictures that are not present in the bitstream and the leading picture associated with the CRA picture is not decodable when the random access point picture is the CRA picture and the random access happens to the CRA picture.
4. The video decoding method of claim 3 , wherein pictures that follow the leading picture associated with the CRA picture, in decoding order, are decoded after a predetermined delay time.
5. The video decoding method of claim 3 , wherein types of leading pictures comprise a non-decodable picture type and a decodable picture type, and the leading picture is the non-decodable picture type.
6. The video decoding method of claim 1 , wherein the leading picture associated with CRA picture has the non-decodable picture type and the leading picture associated with the IDR picture has the decodable picture type.
7. The video decoding method of claim 3 , wherein the leading picture associated with the CRA picture refers to a reference picture that is not present in the bitstream.
8. The video decoding method of claim 3 , further comprising receiving flag information indicating that the at least one reference picture for the leading picture associated with the CRA picture is unavailable.
9. The video decoding method of claim 8 , further comprising outputting error information of the bitstream and decoding pictures after the leading picture associated with the CRA picture when the at least one reference picture for the leading picture associated with the CRA picture is determined to be unavailable through the flag information.
10. The video decoding method of claim 3 , wherein the bitstream is determined not to satisfy predetermined conformance when the at least one reference picture for the leading picture associated with the CRA picture is unavailable.
11. The video decoding method of claim 10 , further comprising outputting error information of the bitstream and decoding pictures that follow the leading picture associated with the CRA picture in decoding order.
12. The video decoding method of claim 8 , wherein the flag information is received through a sequence parameter set, and
wherein the flag information corresponds to a broken_link_leading_pics_enable_flag syntax element in the sequence parameter set.
13. The video decoding method of claim 3 , wherein the leading picture associated with the CRA picture is not output when the random access point picture is the CRA picture and flag information is set to 1 as to represent the leading picture associated with the CRA is not output, and
wherein the flag information is set based on properties of the leading picture associated with the CRA picture obtained from the bitstream.