Enhancing audio using a mobile device
Embodiments disclosed herein enable detection and improvement of the quality of the audio signal using a mobile device by determining the loss in the audio signal and enhancing audio by streaming the remainder portion of audio. Embodiments disclosed herein enable an improvement in the sound quality rendered by rendering devices by emitting an test audio signal from the source device, measuring the test audio signal using microphones, detecting variation in the frequency response, loudness and timing characteristics using impulse responses and correcting for them. Embodiments disclosed herein also compensate for the noise in the acoustic space by determining the reverberation and ambient noise levels and their frequency characteristics and changing the digital filters and volumes of the source signal to compensate for the varying noise levels.
1. A method, performed by a mobile device, for improving quality of an audio signal being played back by an audio system that includes a source device and at least one rendering device, the method comprising:
detecting a period of silence in the audio signal;
measuring ambient noise characteristics of an acoustic space responsive to detecting the period of silence;
calculating a frequency response of the ambient noise characteristics;
calculating a digital filter based on the calculated frequency response; and
communicating the digital filter to the source device, the source device being configured to perform adjustments to improve the audio signal based on the digital filter.
2. The method of claim 1 , wherein the ambient noise characteristics comprise frequency characteristics and a loudness level of noise during the period of silence.
3. The method of claim 2 , wherein the loudness level is measured using a weighting filter based at least on A-weights or C-weights.
4. The method of claim 2 , further comprising:
estimating a volume level of the audio signal based on the loudness level; and
communicating settings related to the volume level to the source device.
5. The method of claim 1 , wherein the calculating the frequency response of the ambient noise characteristics comprises calculating the frequency response using a Fast Fourier Transform (FFT) of the ambient noise characteristics.
6. The method of claim 1 , wherein the calculating the digital filter based on the calculated frequency response comprises calculating the digital filter using an inverse of the calculated frequency response.
7. The method of claim 1 , wherein the digital filter is a least one of an infinite impulse response filter or a finite impulse response filter.
8. A computer program product comprising computer executable program code recorded on a computer readable non-transitory storage medium, said computer executable program code when executed, performing a method for improving quality of an audio signal being played back on an audio system that includes a source device and at least one rendering device, the method comprising:
detecting a period of silence in the audio signal;
measuring ambient noise characteristics of an acoustic space responsive to detecting the period of silence;
calculating a frequency response of the ambient noise characteristics;
calculating a digital filter based on the calculated frequency response; and
communicating the digital filter to the source device, the source device being configured to perform adjustments to improve the audio signal based on the digital filter.
9. The computer program product of claim 8 , wherein the ambient noise characteristics comprise frequency characteristics and a loudness level of noise during the period of silence.
10. The computer program product of claim 9 , wherein the loudness level is measured using weighting filter based at least on A-weights or C-weights.
11. The computer program product of claim 9 , further comprising:
estimating a volume level of the audio signal based on the loudness level; and
communicating settings related to the volume level to the source device.
12. The computer program product of claim 8 , wherein the calculating the frequency response of the ambient noise characteristics comprises calculating the frequency response using a Fast Fourier Transform (FFT) of the ambient noise characteristics.
13. The computer program product of claim 8 , wherein the calculating the digital filter based on the calculated frequency response comprises calculating the digital filter using an inverse of the calculated frequency response.
14. A mobile device configured to obtain a digital filter for improving quality of an audio signal being played back by an audio system that includes a source device and at least one rendering device, comprising:
at least one microphone configured to detect the audio signal; and
a processing unit configured to:
detect a period of silence in the detected audio signal;
measure ambient noise characteristics of an acoustic space responsive to detecting the period of silence;
calculate a frequency response of the ambient noise characteristics;
calculate a digital filter based on the calculated frequency response; and
communicate the digital filter to the source device, the source device being configured to perform adjustments to improve the audio signal based on the digital filter.
15. The mobile device of claim 14 , wherein the ambient noise characteristics comprise frequency characteristics and a loudness level of noise during the period of silence.
16. The mobile device of claim 15 , wherein the loudness level is measured using weighting filter based at least on A-weights or C-weights.
17. The mobile device of claim 14 , wherein the processing unit is further configured to:
estimate a volume level of the detected audio signal based on the loudness level; and
communicate settings related to the volume level to the source device.
18. The mobile device of claim 14 , wherein the processing unit is further configured to:
calculate the frequency response of the ambient noise characteristics using a Fast Fourier Transform (FFT) of the ambient noise characteristics.
19. The mobile device of claim 14 , wherein the processing unit is further configured to:
calculate the digital filter using an inverse of the calculated frequency response.
20. The mobile device of claim 14 , wherein the digital filter is a least one of an infinite impulse response filter or a finite impulse response filter.