Methods, apparatus and systems for controlling doppler effect modelling

A method of encoding parameters for use in modelling a Doppler effect when rendering audio content for a 6 degrees of freedom, 6DoF, environment, the method comprising:

• determining first parameter values of one or more first parameters indicative of an allowable range of pitch modification values, wherein the one or more first parameters comprise parameters indicative of upper and/or lower limits of the allowable range of pitch modification values;
• determining a second parameter value of a second parameter indicative of a desired strength of the to-be-modelled Doppler effect;
• encoding indications of the first and second parameter values,
• wherein the first and second parameter values can be used for mapping a relative velocity between a listener and an audio source of the audio content to a pitch modification value based on a predefined pitch modification function, the pitch modification value being used for rendering the audio source, and the predefined pitch modification function having the first and second parameters and being a function for mapping relative velocities to pitch modification values;
• wherein the allowable range of pitch modification values reflects a processing capability of an audio renderer rendering the audio content;
• and
• wherein the second parameter controls a slope of the pitch modification function that reflects aggressiveness of the to-be-modelled Doppler effect.