Image encoding/decoding method and device for determining sub-layers on basis of required number of sub-layers, and bit-stream transmission method

An image decoding method performed by an image decoding apparatus, the image decoding method comprising:

• determining at least one layer in an output layer set (OLS);
• and
• determining a number of sublayers for the at least one layer,
• wherein a number of sublayers for a current layer in the OLS is determined based on a maximum number of needed sublayers for a direct referencing layer which is a layer capable of directly referencing the current layer.

An image encoding method performed by an image encoding apparatus, the image encoding method comprising:

• determining at least one layer in an output layer set (OLS);
• and
• determining a number of sublayers for the at least one layer,
• wherein the number of sublayers for a current layer in the OLS is determined based on a maximum number of needed sublayers for a direct referencing layer which is a layer capable of directly referencing the current layer.

A method for transmitting a bitstream generated by an image encoding method, the image encoding method comprising:

• determining at least one layer in an output layer set (OLS);
• and
• determining a number of sublayers for the at least one layer,
• wherein the number of sublayers for a current layer in the OLS is determined based on a maximum number of needed sublayers for a direct referencing layer which is a layer capable of directly referencing the current layer.