Method and apparatus for decoding an audio signal

An apparatus for decoding an audio signal, the apparatus comprising:

• a hardware decoding device configured for:
• receiving a head-related transfer function (HRTF);
• applying the HRTF to spatial information to generate surround converting information;
• and
• outputting the surround converting information;
• wherein:
• the HRTF is used to give pseudo-surround effect to a downmix signal corresponding to a mono signal or a stereo signal;
• the surround converting information is to generate a pseudo-surround signal by being applied to the downmix signal, the pseudo-surround signal comprising a first output channel signal and a second output channel signal;
• and,
• the spatial information is determined when a plurality of channels are downmixed into the downmix signal, and used to generate a multi-channel signal from the downmix signal.