Figure 3 show a flow diagram of the operation of the metadata encoder as shown in Figure 2 according to some embodiments; 

Figure 4 shows schematically the metadata decoder according to some embodiments; 

Figure 5 show a flow diagram of the operation of a metadata decoder as shown in Figure 4 according to some embodiments; and 

Figure 6 shows schematically an example device suitable for implementing the apparatus shown. 

## Embodiments of the Application 

The following describes in further detail suitable apparatus and possible mechanisms for the provision of effective spatial analysis derived metadata parameters. In the following discussions multi-channel system is discussed with respect to a multi-channel microphone implementation. Flowever as discussed above the input format may be any suitable input format, such as multi-channel loudspeaker, ambisonic (FOA/FIOA) etc. It is understood that in some embodiments the channel location is based on a location of the microphone or is a virtual location or direction. Furthermore the output of the example system is a multi-channel loudspeaker arrangement. Flowever it is understood that the output may be rendered to the user via means other than loudspeakers. Furthermore the multi- channel loudspeaker signals may be generalised to be two or more playback audio signals. 

The metadata consists at least of elevation, azimuth and the energy ratio of a resulting direction, for each considered time/frequency subband. The direction parameter components, the azimuth and the elevation are extracted from the audio data and then quantized to a given quantization resolution. The resulting indexes must be further compressed for efficient transmission. For high bitrate, high quality lossless encoding of the metadata is needed. 

The concept as discussed hereafter is to combine a fixed bitrate coding approach with variable bitrate coding that distributes encoding bits for data to be compressed between different segments, such that the overall bitrate per frame is 

