Audio control using auditory event detection
In one disclosed aspect, modifications are applied to an audio signal at least partly in response to auditory events. In another aspect, an input channel is divided into auditory events by detecting changes in a measurable characteristic of the input signal.
1. A method for processing an audio signal in an audio processing apparatus, the method comprising:
monitoring a characteristic of the audio signal;
identifying a change in the characteristic;
establishing an auditory event boundary to identify the change in the characteristic, wherein an audio portion between consecutive auditory event boundaries constitutes an auditory event; and
applying a modification to the audio signal based in part on an occurrence of an auditory event,
wherein the audio processing apparatus is implements at least in part in hardware.
2. The method of claim 1 wherein the characteristic includes loudness.
3. The method of claim 1 wherein the characteristic includes perceived loudness.
4. The method of claim 1 wherein the characteristic includes phase.
5. The method of claim 1 wherein the characteristic 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 applying a modification modifies a gain-smoothing time constant.
10. The method of claim 1 wherein the applying a modification further comprises modifying a gain gradually as the gain is applied to consecutive auditory events so that the gain is not disjoint over time.
11. The method of claim 1 wherein the applying a modification further comprises generating a second audio signal based on the audio signal, wherein the second signal is an enhanced version of the audio signal.
12. 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.
13. 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.
14. The method of claim 1 wherein a size of the auditory event includes one or more whole blocks of data.
15. A non-transitory computer-readable storage medium encoded with a computer program for causing a computer to perform the method of claim 1 .
16. A method performed in an audio processing device in which a processor of the device receives an input signal and generates an output signal, comprising:
detecting changes in a measurable characteristic of the input signal;
identifying a change in the measurable characteristic of the input signal;
classifying a location in the input signal near the change as an auditory event boundary, wherein an audio segment between consecutive auditory event boundaries constitutes an auditory event;
generating one or more parameters in response to the auditory event; and
applying a modification to the input signal based on the one or more parameters to generate the output signal,
wherein the audio processing device is implemented at least in part in hardware.
17. The method of claim 16 wherein the input signal includes two or more audio channels and the measurable characteristic is a phase difference between at least two or the two more audio channels.
18. The method of claim 16 wherein the input signal includes two of more audio channels and the measurable characteristic is a correlation between at least two of the two more audio channels.
19. The method of claim 16 wherein applying a modification further comprises smoothing a gain applied to the input signal.
20. The method of claim 16 wherein the classified location coincides with a boundary of a block of data in the input signal.
21. The method of claim 16 further comprising adjusting the classified location to coincide with a boundary of a block of data in the input signal.
22. A non-transitory computer-readable storage medium encoded with a computer program for causing a computer to perform the method of claim 16 .