Video decoding method and device

A video decoding method performed by a video decoding device, the method comprising:

• obtaining a parameter indicating whether a multiple transform set (MTS) can be applied to a decoding block, and information on a size of the decoding block;
• determining a transform type of the decoding block based on the parameter indicating whether the multiple transform set (MTS) can be applied to the decoding block and the information on the size of the decoding block;
• and
• setting a zero-out area of the decoding block based on the parameter indicating whether the multiple transform set (MTS) can be applied to the decoding block and the information on the size of the decoding block,
• wherein whether or not syntax information with regard to a maximum transform size in which a transform process can be performed for the decoding block is signaled to the video decoding device depends on whether a block size is greater than a predetermined size.