The spatial analyser 203 may thus be configured to provide at least one azimuth and elevation for each frequency band and temporal time-frequency block within a frame of an audio signal, denoted as azimuth (p(k,n) and elevation 0(k,n). The direction parameters 108 may be also be passed to a direction index generator 205. 

The spatial analyser 203 may also be configured to determine an energy ratio parameter 110. The energy ratio may be considered to be a determination of the energy of the audio signal which can be considered to arrive from a direction. The direct-to-total energy ratio r(k,n) can be estimated, e.g., using a stability measure of the directional estimate, or using any correlation measure, or any other suitable method to obtain a ratio parameter. The energy ratio may be passed to an energy ratio analyser 221 and an energy ratio combiner 223. 

Therefore in summary the analysis processor is configured to receive time domain multichannel or other format such as microphone or ambisonic audio signals. 

Following this the analysis processor may apply a time domain to frequency domain transform (e.g. STFT) to generate suitable time-frequency domain signals for analysis and then apply direction analysis to determine direction and energy ratio parameters. 

The analysis processor may then be configured to output the determined parameters. 

Although directions and ratios are here expressed for each time index n, in some embodiments the parameters may be combined over several time indices. Same applies for the frequency axis, as has been expressed, the direction of several frequency bins b could be expressed by one direction parameter in band k consisting of several frequency bins b. The same applies for all of the discussed spatial parameters herein. 

As also shown in Figure 2 an example metadata encoder/quantizer 111 is shown according to some embodiments. 

The metadata encoder/quantizer 111 may comprise an energy ratio analyser (or quantization resolution determiner) 221 . The energy ratio analyser 221 may be 

