The object-based audio is one of the spatial audio representations providing an immersive audio experience. While it can be found in a wide variety of audio reproduction systems, its use in communication systems is very limited as it faces many constraints like the complexity of the system, short delay, or limited available bitrate for coding and transmission. This paper presents a new bitrate adaptation method to be used in object-based audio coding systems that overcomes these constraints and enables their use in 5G voice and audio communication systems. The presented method distributes an available codec bit budget to encode waveforms of the individual audio objects based on a classification of the objects’ subjective importance in particular frames. The presented method has been used in the Immersive Voice and Audio Services (IVAS) codec, recently standardized by 3GPP, but it can be employed in other codecs as well. Test results show the performance advantage of the bitrate adaptation method over the conventional uniformly distributed bitrate method. The paper also presents IVAS selection test results for object-based audio with four audio objects, rendered to binaural headphone representation, in which the presented method plays a substantial role.
