Concept for audio encoding and decoding for audio channels and audio objects

Audio encoder for encoding audio input data (101) to obtain audio output data (501) comprises an input interface (100) for receiving a plurality of audio channels, a plurality of audio objects and metadata related to one or more of the plurality of audio objects; a mixer (200) for mixing the plurality of objects and the plurality of channels to obtain a plurality of pre-mixed channels, each pre-mixed channel comprising audio data of a channel and audio data of at least one object; a core encoder (300) for core encoding core encoder input data; and a metadata compressor (400) for compressing the metadata related to the one or more of the plurality of audio objects, wherein the audio encoder is configured to operate in at least one mode of the group of two modes comprising a first mode, in which the core encoder is configured to encode the plurality of audio channels and the plurality of audio objects received by the input interface as core encoder input data, and a second mode, in which the core encoder (300) is configured for receiving, as the core encoder input data, the plurality of pre-mixed channels generated by the mixer (200)