Dynamic range control

A method for adjusting the dynamic range of an output audio signal, comprising:

• providing a dynamic range tolerance window to define a transfer function for a listening environment with a predetermined noise floor;
• computing an average value for an input audio signal over a predetermined psychoacoustic timescale;
• using the average to generate a gain value to shift the dynamic range tolerance window to align a linear portion of the transfer function with the average value;
• and
• using the input audio signal to generate the output audio signal, the output audio signal having a dynamic range substantially confined within the dynamic range tolerance window.

A system for processing an audio signal, comprising:

• a signal processor to:
• receive data representing an input audio signal;
• map the dynamic range of the input audio signal to an output dynamic range using a transfer function selected on the basis of a listening environment defining a noise floor and with a linear portion aligned to an average level of the input audio signal;
• and
• generate an output audio signal with the output dynamic range, from the input audio signal.

A computer program embedded on a non-transitory tangible computer readable storage medium, the computer program including machine readable instructions that, when executed by a processor, implement a method for adjusting dynamic range of an audio signal comprising:

• receiving data representing a user selection for a dynamic range tolerance to define a transfer function for a listening environment with a predetermined noise floor;
• determining a transfer function based on the dynamic range tolerance;
• and
• processing an input audio signal to generate an output audio signal using the transfer function by maintaining an average level of the input audio signal within a range defined by the user selection.

A computer-implemented method, comprising:

• at a device with a display:
• displaying a relative loudness level control to control the volume level of an output audio signal of the device, the relative loudness level control including a dynamic resizable window control to control dynamic range of the output audio signal;
• and
• processing an input audio signal to constrain an average value of the relative loudness level for that signal within a selected central region of the window control to control the dynamic range of the output audio signal.

A device, comprising:

• a display;
• one or more processors;
• memory;
• and
• one or more programs stored in the memory and including instructions which are configured to be executed by the one or more processors to:
• display a relative loudness level control module to control a relative loudness level and a dynamic range for an output audio signal output from the device;
• control the size and position of a dynamic range control window in response to user input;
• and
• control a dynamic range of the output audio signal on the basis of the size and position of the dynamic range control window by constraining an average value of the relative loudness level for an input audio signal within a selected central region of the control window.