Method and system for providing an excitation-pattern based audio coding scheme
View Patent ↗An improved audio compression scheme is provided. The scheme uses an excitation pattern to more efficiently provide audio signal compression. Under the scheme, an input signal is transformed to the frequency domain. Next, the excitation pattern corresponding to the transformed input signal is calculated. Bit allocation processing is then performed based on the excitation pattern. Frequencies are then coded based on the results of the bit allocation processing. Finally, bitstream packing is performed to generate the output coded audio bit stream. In one exemplary implementation, the audio compression scheme is implemented in an encoder.
1. A method for providing audio compression in an encoder, comprising:
transforming an input audio signal into a frequency domain representation to produce a transformed audio input signal;
calculating an excitation pattern representing the magnitude of an output of auditory filters in response to an input signal as a function of filter center frequency corresponding to the transformed input audio signal including replacing a magnitude spectrum of the input audio signal with the corresponding excitation pattern using simulated auditory filters whose sides are modeled as an intensity weighting function;
performing bit allocation and quantization based on the magnitudes of different bits in the excitation pattern, without using a masked threshold, to generate bit-allocation results and quantization results;
coding a plurality of frequencies based on the bit-allocation results; and
performing bitstream packing based on the quantization results and coding results to generate a compressed coded audio output signal.
2. The method of claim 1 wherein transforming the input audio signal into the frequency domain further comprises:
using a fast Fourier transform to transform the input audio signal.
3. The method of claim 1 further comprising:
transmitting the coded audio output signal; and
performing an inverse transform of the excitation pattern on the coded audio output signal to obtain a decoded audio signal.
4. The method of claim 3 wherein the inverse transform is an inverse fast Fourier transform.
5. The method of claim 1 further comprising:
transmitting the coded audio output signal;
performing a deconvolution process of the excitation pattern to generate a deconvolution process output; and
performing an inverse transform of the deconvolution process output to obtain a decoded audio signal.
6. The method of claim 5 wherein the inverse transform is an inverse fast Fourier transform.
7. A system for providing audio compression, comprising:
an integrated circuit chip configured to:
transform an input audio signal into a frequency domain representation to produce a transformed input audio signal;
calculate an excitation pattern representing the magnitude of an output of auditory filters in response to an input signal as a function of filter center frequency corresponding to the transformed input audio signal including replacing a magnitude spectrum of the input audio signal with the corresponding excitation pattern using simulated auditory filters whose sides are modeled as an intensity weighting function;
perform bit allocation and quantization based on the magnitudes of different bits in the excitation pattern, without using a masked threshold, to generate bit-allocation results and quantization results;
code a plurality of frequencies based on the bit-allocation results; and
perform bitstream packing based on the quantization results and coding results to generate a compressed coded audio output signal.
8. The system of claim 7 wherein the input audio signal is transformed into the frequency domain further using a fast Fourier transform.
9. The system of claim 7 wherein the integrated circuit chip is further configured to:
perform an inverse transform of the excitation pattern on the coded audio output signal to obtain a decoded audio signal.
10. The system of claim 9 wherein the inverse transform is an inverse fast Fourier transform.
11. The system of claim 7 wherein the integrated circuit chip is further configured to:
perform a deconvolution process of the excitation pattern to generate a deconvolution process output; and
perform an inverse transform of the deconvolution process output to obtain a decoded audio signal.
12. The system of claim 11 wherein the inverse transform is an inverse fast Fourier transform.