Audio decoder with dynamic adjustment of signal modification
Methods and devices for dynamically adjusting a multi-band signal-modification profile based on a psychoacoustic model are disclosed. In one arrangement, the encoding parameter side information is used to estimate encoding noise of an encoded signal. The signal spectrum of the signal is estimated. Adjustments to the multi-band signal-modification profile are determined using the estimated noise and signal spectrum and a psychoacoustic profile.
1. A method of dynamically modifying a signal-modification profile to account for noise, including:
providing an auditory perception model;
providing a multi-band audio signal-modification profile;
receiving a stream of data including an encoded audio signal and encoding parameter data;
estimating a signal spectrum of the stream of data that has been received;
estimating encoding noise based on the encoding parameter data that has been received;
determining profile adjustments for the audio signal-modification profile in one or more frequency bands based on at least the estimated signal spectrum, the estimated encoding noise and the auditory perception model;
applying the adjustments to the audio signal-modification profile in the one or more frequency bands; and
processing the encoded audio signal using the audio signal-modification profile after adiustments.
2. The method of claim 1 , wherein the auditory perception model comprises an excitation level based model.
3. The method of claim 2 , wherein the excitation model takes into account temporal masking.
4. The method of claim 1 , wherein the auditory perception model comprises a psychoacoustic model 1 or 2 of an MPEG-1 standard.
5. The method of claim 1 , wherein the multi-band audio signal modification profile comprises linear band-wise equalization.
6. The method of claim 1 , wherein the multi-band audio signal modification profile comprises an auditory profile of a particular listener.
7. The method of claim 1 , wherein the multi-band audio signal modification profile comprises an auditory profile adapted to a hearing loss.
8. The method of claim 1 , wherein the multi-band audio signal modification profile comprises an auditory profile adapted to an environmental background sound that causes masking.
9. The method of claim 1 , wherein the stream of data represents 32 or more spectral bands.
10. The method of claim 9 , wherein the stream of data complies with an MPEG standard.
11. The method of claim 9 , wherein the stream of data complies with an MPEG-1 layer 3 standard.
12. The method of claim 1 , wherein the encoding parameter data includes quantization numbers.
13. The method of claim 12 , wherein the stream of data complies with an MPEG standard.
14. The method of claim 12 , wherein the stream of data complies with an MPEG-1 layer 3 standard.
15. The method of claim 1 , wherein the determining profile adjustments applies the auditory perception model to determine an adjustment that does not promote encoding noise to audible levels.
16. The method of claim 15 , wherein the profile adjustments are determined iteratively.
17. A component device that dynamically modifies a multi-band audio signal-modification profile responsive to an auditory perception model, including:
a processor having an input, the input receiving a stream of data including an encoded audio signal and encoding parameter data;
logic operable on the processor to
estimate a signal spectrum from the stream of data that has been received;
estimate encoding noise based on the encoding parameter data that has been received;
determine profile adjustments for the multi-band audio signal-modification profile in one or more frequency bands based on the estimated signal spectrum, the estimated encoding noise and the auditory perception model; and
apply the adjustments to the audio signal-modification profile in the one or more frequency bands.
18. The device of claim 17 , wherein the auditory perception model comprises an excitation level based model.
19. The device of claim 18 , wherein the excitation model takes into account temporal masking.
20. The device of claim 17 , wherein the auditory perception model comprises a psychoacoustic model 1 or 2 of an MPEG-1 standard.
21. The device of claim 17 , wherein the multi-band audio signal modification profile comprises linear band-wise equalization.
22. The device of claim 17 , wherein the multi-band audio signal modification profile comprises an auditory profile of a particular listener.
23. The device of claim 17 , wherein the multi-band audio signal modification profile comprises an auditory profile adapted to a hearing loss.
24. The device of claim 17 , wherein the multi-band audio signal modification profile comprises an auditory profile adapted to an environmental background sound that causes masking.
25. The device of claim 17 , wherein the stream of data represents 32 or more spectral bands.
26. The device of claim 25 , wherein the stream of data complies with an MPEG standard.
27. The device of claim 25 , wherein the stream of data complies with an MPEG-1 layer 3 standard.
28. The device of claim 17 , wherein the encoding parameter data includes a number of bits used to quantize a spectral band.
29. The device of claim 28 , wherein the stream of data complies with an MPEG standard.
30. The device of claim 28 , wherein the stream of data complies with an MPEG-1 layer 3 standard.
31. The device of claim 17 , wherein the determining profile adjustments applies the auditory perception model to determine an adjustment that does not promote encoding noise to audible levels.
32. The device of claim 31 , wherein the profile adjustments are determined iteratively.