Binaural rendering apparatus and method for playing back of multiple audio sources

A method of generating a binaural headphone playback signals given the multiple audio source signals with an associated metadata and binaural room impulse response (BRIR) database, wherein the audio source signals can be channel-based, object-based, or a mixture of both signals, the method comprising:

• computing instant head-relative positions of the audio sources with respect to a position of user head and facing direction;
• grouping the source signals according to the instant head-relative positions of the audio sources in a hierarchical manner;
• parameterizing BRIR to be used for rendering;
• dividing each source signal to be rendered into a number of blocks and frames;
• averaging the parameterized BRIR sequences identified with a hierarchically grouping result;
• and
• downmixing the divided source signals identified with the hierarchically grouping result.