Method and device for coding image/video on basis of prediction weighted table

A video encoding method comprising:

• deriving motion information on a current block;
• performing weighted prediction on the current block based on the motion information;
• and
• encoding image information comprising a first flag, a second flag and information on the weighted prediction, wherein a third flag is comprised in the encoded image information based on the first flag or the second flag,
• wherein the first flag is related to whether weighted prediction is applied to P slices referring to a picture parameter set, the second flag related to whether the weighted prediction is applied to B slices referring to the picture parameter set, the third flag is related to whether information on the weighted prediction is present in a picture header, and the third flag is comprised in the picture parameter set based on the third flag being comprised in the encoded image information,
• wherein the information on the weighted prediction comprises a prediction weighted table syntax,
• wherein the prediction weighted table syntax is comprised in the picture header or the slice header based on the third flag,
• wherein whether L0 number information for the weighted prediction is configured to be parsed from the prediction weighted table syntax is determined based on the third flag,
• wherein whether L1 number information for the weighted prediction is configured to be parsed from the prediction weighted table syntax is determined based on the third flag,
• wherein the L0 number information represents a number of weighted reference pictures in a reference picture list 0, and
• wherein the L1 number information represents a number of weighted reference pictures in a reference picture list 1.

A transmission method of data for a video, the method comprising:

• obtaining a bitstream for the video, wherein the bitstream is generated based on deriving motion information on a current block, performing weighted prediction on the current block based on the motion information, and encoding image information comprising a first flag, a second flag and information on the weighted prediction, wherein a third flag is comprised in the encoded image information based on the first flag or the second flag;
• and
• transmitting the data comprising the bitstream,
• wherein the first flag is related to whether weighted prediction is applied to P slices referring to a picture parameter set, the second flag related to whether the weighted prediction is applied to B slices referring to the picture parameter set, the third flag is related to whether information on the weighted prediction is present in a picture header, and the third flag is comprised in the picture parameter set based on the third flag being comprised in the encoded image information,
• wherein the information on the weighted prediction comprises a prediction weighted table syntax,
• wherein the prediction weighted table syntax is comprised in the picture header or the slice header based on the third flag,
• wherein whether L0 number information for the weighted prediction is configured to be parsed from the prediction weighted table syntax is determined based on the third flag,
• wherein whether L1 number information for the weighted prediction is configured to be parsed from the prediction weighted table syntax is determined based on the third flag,
• wherein the L0 number information represents a number of weighted reference pictures in a reference picture list 0, and
• wherein the L1 number information represents a number of weighted reference pictures in a reference picture list 1.