Method and apparatus for processing an audio signal based on an estimated loudness

1. A method for processing audio and speech signals comprising:

receiving an indication for a mode of operation of an apparatus;

receiving a first audio signal during the mode of operation;

determining a target loudness level for playback of at least one of audio and speech signals based on the mode of operation;

determining whether the first audio signal comprises speech or non-speech frames wherein said non-speech frames comprise silence or audio portions;

determining a loudness estimate, wherein the loudness estimate is generated for at least one frame when the at least one frame is determined to be speech and the loudness estimate is generated differently for the at least one frame when the at least one frame is determined to be a non-speech signal during the mode of operation;

generating at least one signal processing parameter dependent on the loudness estimate when the at least one frame is the at least one of audio and speech signals during the mode of operation; and

adjusting the first audio signal with the at least one signal processing parameter relative to the target loudness level.

2. The method as claimed in claim 1 , wherein determining a loudness estimate comprises applying at least one loudness model to the first audio signal.

3. The method as claimed in claim 2 , wherein the at least one loudness model comprises at least one of:

a digital filter; and

a parametric filter.

4. The method as claimed in claim 2 , wherein the at least one loudness model comprises a speech loudness model to be applied to the first audio signal when the first audio signal comprises a speech frame.

5. The method as claimed in claim 2 , wherein the at least one loudness model stimulates properties of a human auditory system.

6. The method as claimed in claim 1 , wherein determining the loudness estimate further comprises applying an environmental model.

7. The method as claimed in claim 6 , wherein the environmental model comprises at least one of:

a loudspeaker model comprising at least one filter simulating the audio filtering of an integrated hands free loudspeaker;

an earpiece model comprising at least one filter simulating the audio filtering of an earpiece transducer and housing;

a headset model comprising at least one filter simulating the audio filtering of a predetermined headset; and

a mechanical model comprising at least one filter simulating the mechanical acoustical response of the apparatus.

8. The method as claimed in claim 1 , wherein the at least one signal processing parameter comprises at least one of:

a gain control parameter applied to an amplifier configured to control the first audio signal;

a dynamic range parameter applied to a dynamic range processor configured to control the first audio signal; and

a dynamic level parameter applied to a dynamic level controller configured to control the first audio signal.

9. The method as claimed in claim 1 , wherein generating at least one signal processing parameter dependent on the loudness estimate comprises:

comparing the loudness estimate with a loudness input value; and

generating the at least one signal processing parameter dependent on a difference between the loudness estimate of the first audio signal and the loudness input value.

10. The method as claimed in claim 1 , wherein the first audio signal comprises different types of music genres.

11. The method as claimed in claim 1 , wherein determining the loudness estimate further comprises applying an acoustic model to estimate perceived loudness, wherein the acoustic model further considers surrounding acoustical properties.

12. The method as claimed in claim 1 , further comprising:

adaptively adjusting the at least one signal processing parameter based on the loudness estimate.

13. The method as claimed in claim 1 , further comprising:

receiving audio input from an environment to determine surrounding acoustical properties.

14. An apparatus for processing audio and speech signals comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to:

receive an indication for a mode of operation of the apparatus;

receive a first audio signal during the mode of operation;

determine a target loudness level for playback of audio and speech signals based on the mode of operation;

determine whether the first audio signal comprises speech or non-speech frames, wherein said non-speech frames comprise silence or audio portions;

determine a loudness estimate, wherein the loudness estimate is generated for at least one frame when the at least one frame is determined to be speech and the loudness estimate is generated differently for the at least one frame when the at least one frame is determined to be a non-speech signal during the mode of operation;

generate at least one signal processing parameter dependent on the loudness estimate when the at least one frame is the at least one of audio and speech signals during the mode of operation; and

adjust the first audio signal with the at least one signal processing parameter relative to the target loudness level.

15. The apparatus as claimed in claim 14 , wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to apply at least one loudness model to the first audio signal.

16. The apparatus as claimed in claim 15 , wherein the at least one loudness model comprises at least one of:

a digital filter; and

a parametric filter.

17. The apparatus as claimed in claim 15 , wherein the at least one loudness model stimulates properties of a human auditory system.

18. The apparatus as claimed in claim 14 , wherein the at least one loudness model comprises a speech loudness model to be applied to the first audio signal when the first audio signal comprises a speech frame.

19. The apparatus as claimed in claim 14 , wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to apply an environmental model.

20. The apparatus as claimed in claim 19 , wherein the environmental model comprises at least one of:

a loudspeaker model comprising at least one filter simulating the audio filtering of an integrated hands free loudspeaker;

an earpiece model comprising at least one filter simulating the audio filtering of an earpiece transducer and housing;

a headset model comprising at least one filter simulating the audio filtering of a predetermined headset; and

a mechanical model comprising at least one filter simulating the mechanical acoustical response of the apparatus.

21. The apparatus as claimed in claim 14 , wherein the at least one signal processing parameter comprises at least one of:

a gain control parameter applied to an amplifier configured to control the first audio signal;

a dynamic range parameter applied to a dynamic range processor configured to control the first audio signal; and

a dynamic level parameter applied to a dynamic level controller configured to control the first audio signal.

22. The apparatus as claimed in claim 14 , wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to:

compare the loudness estimate with a loudness input value; and

generate the at least one signal processing parameter dependent on a difference between the loudness estimate of the first audio signal and the loudness input value.

23. The apparatus as claimed in claim 14 , wherein the first audio signal comprises different types of music genres.

24. The apparatus as claimed in claim 14 , wherein determining the loudness estimate further comprises applying an acoustic model to estimate perceived loudness, wherein the acoustic model further considers surrounding acoustical properties.

25. The apparatus as claimed in claim 14 , wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus at least to perform:

adaptively adjust the at least one signal processing parameter based on the loudness estimate.

26. The apparatus as claimed in claim 14 , wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus to:

receive audio input from an environment to determine surrounding acoustical properties.