Background noise estimation using gap confidence

One or more non-transitory media having software stored thereon, the software including instructions for controlling one or more devices to perform a method, the method comprising:

• receiving microphone output signals from a microphone of a playback environment, the microphone output signals corresponding to playback content reproduced by one or more loudspeakers and detected by the microphone, the microphone signals also corresponding to background noise in the playback environment detected by the microphone;
• receiving playback content values corresponding to the playback content;
• generating gap confidence values in response to the microphone output signals and the playback content values, where each of the gap confidence values is for a different time, t, and is indicative of a confidence that there is a gap, at the time t, in the playback content, wherein a gap denotes a time or time interval at or in which playback content is missing or has a level less than a predetermined threshold, and wherein generating the gap confidence values includes generating a gap confidence value for each time, t, including by:
• determining a minimum in the playback content values for the time, t;
• processing the microphone output signals to determine a smoothed level of the microphone output signals for the time, t;
• and
• determining the gap confidence value for the time, t, to be indicative of how different the minimum in playback content values for the time, t, is from the smoothed level of the microphone output signals for the time, t;
• and
• generating an estimate of background noise in the playback environment using the gap confidence values.

An apparatus, comprising:

• an input system configured for:
• receiving microphone output signals from a microphone of a playback environment, the microphone output signals corresponding to playback content reproduced by one or more loudspeakers and detected by the microphone, the microphone signals also corresponding to background noise in the playback environment detected by the microphone;
• and
• receiving playback content values corresponding to the playback content;
• and
• a noise estimation subsystem configured for generating gap confidence values in response to the microphone output signals and the playback content values, where each of the gap confidence values is for a different time, t, and is indicative of a confidence that there is a gap, at the time t, in the playback content, wherein a gap denotes a time or time interval at or in which playback content is missing or has a level less than a predetermined threshold, and wherein generating the gap confidence values includes generating a gap confidence value for each time, t, including by:
• determining a minimum in the playback content values for the time, t;
• processing the microphone output signal to determine a smoothed level of the microphone output signals for the time, t;
• and
• determining the gap confidence value for the time, t, to be indicative of how different the minimum in playback content values for the time, t, is from the smoothed level of the microphone output signals for the time, t;
• and
• generating an estimate of background noise in the playback environment using the gap confidence values.