Audio control using auditory event detection
In some embodiments, a method for processing an audio signal in an audio processing apparatus is disclosed. The method includes receiving an audio signal and a parameter, the parameter indicating a location of an auditory event boundary. An audio portion between consecutive auditory event boundaries constitutes an auditory event. The method further includes applying a modification to the audio signal based in part on an occurrence of the auditory event. The parameter may be generated by monitoring a characteristic of the audio signal and identifying a change in the characteristic.
1. A method for processing an audio signal in an audio processing apparatus, the method comprising:
receiving the audio signal, the audio signal comprising at least one channel of audio content;
dividing the audio signal into a plurality of subband signals with an analysis filterbank, each of the plurality of subband signals including at least one subband sample;
deriving a characteristic of the audio signal, wherein the characteristic is a power measure of the audio signal;
smoothing the power measure to generate a smoothed power measure of the audio signal;
detecting a location of an auditory event boundary by monitoring the smoothed power measure, wherein an audio portion between consecutive auditory event boundaries constitutes an auditory event,
generating a gain vector based on the location of the auditory event boundary;
applying the gain vector to a version of the plurality of subband signals to generate modified subband signals; and
synthesizing the modified subband signals with a synthesis filterbank to produce a modified audio signal,
wherein the detecting further includes applying a threshold to the smoothed power measure to detect the location of the auditory event boundary,
wherein the detecting further includes comparing the smoothed power measure with a second smoothed power measure of the audio signal,
wherein the power measure or the second power measure is based on a difference measure,
wherein auditory event is associated with a transient, and
wherein the audio processing apparatus is implemented at least in part with hardware.
2. The method of claim 1 wherein the characteristic further includes loudness.
3. The method of claim 1 wherein the characteristic further includes perceived loudness.
4. The method of claim 1 wherein the characteristic further includes phase.
5. The method of claim 1 wherein the characteristic further includes a sudden change in signal power.
6. The method of claim 1 wherein the audio signal includes two or more channels of audio content and the auditory event boundary is identified by examining changes in the characteristic between the two or more channels.
7. The method of claim 6 wherein the characteristic includes interchannel phase difference.
8. The method of claim 6 wherein the characteristic includes interchannel correlation.
9. The method of claim 1 wherein the auditory event boundary coincides with a beginning or end of a block of data in the audio signal.
10. The method of claim 1 further comprising adjusting the auditory event boundary to coincide with a boundary of a block of data in the audio signal.
11. A non-transitory computer-readable storage medium encoded with a computer program for causing a computer to perform the method of claim 1 .
12. An audio processing apparatus, the apparatus comprising:
an input interface for receiving the audio signal, the audio signal comprising at least one channel of audio content;
an analysis filter bank for dividing the audio signal into a plurality of subband signals, each of the plurality of subband signals including at least one subband sample;
a processor that:
derives a characteristic of the audio signal, wherein the characteristic is a power measure of the audio signal;
smooths the power measure to generate a smoothed power measure of the audio signal;
detects a location of an auditory event boundary by monitoring the smoothed power measure, wherein an audio portion between consecutive auditory event boundaries constitutes an auditory event,
generates a gain vector based on the location of the auditory event boundary, and
applies the gain vector to a version of the plurality of subband signals to produce modified subband signals; and
a synthesis filterbank that combines the modified subband signals to produce a modified audio signal,
wherein the detecting further includes applying a threshold to the smoothed power measure to detect the location of the auditory event boundary,
wherein the detecting further includes comparing the smoothed power measure with a second smoothed power measure of the audio signal,
wherein the power measure or the second power measure is based on a difference measure,
wherein auditory event is associated with a transient.