Apparatus, method and computer program for encoding an audio signal or for decoding an encoded audio scene

Apparatus for processing an encoded audio scene comprising, in a first frame, a first soundfield parameter representation and an encoded audio signal, wherein a second frame is an inactive frame, the apparatus comprising:

• an activity detector for detecting that the second frame is the inactive frame;
• a synthetic signal synthesizer for synthesizing a synthetic audio signal for the second frame using the parametric description for the second frame;
• an audio decoder for decoding the encoded audio signal for the first frame;
• and
• a spatial renderer for spatially rendering the audio signal for the first frame using the first soundfield parameter representation and using the synthetic audio signal for the second frame.

Method of processing an encoded audio scene comprising, in a first frame, a first soundfield parameter representation and an encoded audio signal, wherein a second frame is an inactive frame, the method comprising:

• detecting that the second frame is the inactive frame;
• synthesizing a synthetic audio signal for the second frame using the parametric description for the second frame;
• decoding the encoded audio signal for the first frame;
• and
• spatially rendering the audio signal for the first frame using the first soundfield parameter representation and using the synthetic audio signal for the second frame, or generating a meta data assisted output format comprising the audio signal for the first frame, the first soundfield parameter representation for the first frame, the synthetic audio signal for the second frame, and a second soundfield parameter representation for the second frame.