Method and an apparatus for processing an audio signal

An apparatus for processing an audio signal, comprising:

• a receiving unit configured to receive a downmix signal comprising at least one normal object signal, and a bitstream including object information determined when the downmix signal is generated;
• an extension type identifier extracting part configured to extract an extension type identifier indicating whether the downmix signal further comprises a multi-channel object signal, from an extension part of the bitstream;
• a first spatial information extracting part configured to:
• extract first spatial information from the bitstream when the extension type identifier indicates that the downmix signal further comprises the multi-channel object signal, and
• generate second spatial information using the object information and mix information when mode information indicates that the multi-channel object signal is to be suppressed;
• and
• a multi-channel object transcoder configured to transmit one of the first spatial information and the second spatial information,
• wherein the first spatial information is determined when a multi-channel source signal is downmixed into the multi-channel object signal,
• wherein the second spatial information is generated using the object information and mix information, and
• wherein the mix information is to control an object position or object level of the normal object signal.

A non-transitory computer-readable medium having instructions stored thereon, which, when executed by a processor, causes the processor to perform operations, comprising:

• receiving a downmix signal comprising at least one normal object signal, and a bitstream including object information determined when the downmix signal is generated;
• extracting an extension type identifier indicating whether the downmix signal further comprises a multi-channel object signal, from an extension part of the bitstream;
• extracting first spatial information from the bitstream when the extension type identifier indicates that the downmix signal further comprises the multi-channel object signal;
• generating second spatial information using the object information and mix information when mode information indicates that the multi-channel object signal is to be suppressed;
• and
• transmitting one of the first spatial information and the second spatial information, wherein the first spatial information is determined when a multi-channel source signal is downmixed into the multi-channel object signal,
• wherein the second spatial information is generated using the object information and mix information, and
• wherein the mix information is to control an object position or object level of the normal object signal.