Method and device for processing audio signal, using metadata

An audio signal processing device rendering an audio signal including a first element signal,

• the device comprising a processor for obtaining the audio signal including the first element signal and metadata including a first element reference distance information indicating a reference distance of the first element signal and rendering the first element signal on the basis of the first element reference distance information, wherein:
• the audio signal including the first element signal is able to further include a second element signal which is able to be simultaneously rendered with the first element signal;
• the metadata is able to include second element distance information indicating the distance of the second element signal;
• the number of bits required for representing the first element reference distance information is smaller than the number of bits required for representing the second element distance information;
• a set of reference distances which is able to be represented by the first element reference distance information is a subset of a set of distances which is able to be represented by the second element distance information,
• the first element signal is a channel signal or an ambisonics signal, and the second element signal is an object signal, and
• the reference distance of the first element signal represents a radius of a circumference of a speaker layout required to render the first element signal when a listener is position in a sweet spot in a virtual space expressed by the first element signal.