Apparatus and method of audio stabilizing

1. A method comprising:

capturing, by a capturing apparatus, at least two video images at different time instances and at least one spatial audio signal, wherein capturing the at least one spatial audio signal comprises capturing at least one audio signal and determining, from the captured at least one audio signal, at least one audio signal source location relative to the capturing apparatus;

determining from the at least two video images a video image motion value;

deriving, based at least partially on the video image motion value, at least one of:

at least one rotational apparatus motion parameter, and

at least one translational apparatus motion parameter;

determining at least one of: a first offset based on the at least one rotational apparatus motion parameter and a second offset based on the at least one translational apparatus motion parameter; and

stabilizing the captured spatial audio signal based at least partially on at least one of:

compensating for rotational movement of the capturing apparatus based on the first offset, and

compensating for translational movement of the capturing apparatus based on the second offset.

2. The method as claimed in claim 1 , wherein determining from the at least two video images a video image motion value further comprises:

determining at least two local motion values; and

combining the at least two local motion values to generate the video image motion value.

3. The method as claimed in claim 1 , wherein stabilizing the spatial audio signal comprises applying the first offset and/or the second offset to the at least one audio signal source location relative to the capturing apparatus.

4. The method as claimed in claim 1 , wherein deriving the at least one rotational apparatus motion parameter and the at least one translational apparatus motion parameter comprises filtering the at least one rotational apparatus motion parameter and the at least one translational apparatus motion parameter to remove higher frequency values.

5. The method as claimed in claim 4 , further comprising:

determining unintentional movement of the capturing apparatus based on at least one of:

the at least one rotational apparatus motion parameter, and

the at least one translational apparatus motion parameter,

wherein stabilizing the spatial audio signal comprises compensating for the determined unintentional movement.

6. The method as claimed in claim 1 , wherein determining the first offset comprises estimating an amount of the rotational movement of the capturing apparatus based on the at least one rotational apparatus motion parameter, and estimating an angle of the at least one audio signal source location relative to the capturing apparatus following the rotational movement.

7. The method as claimed in claim 6 , wherein compensating for the rotational movement comprises applying the first offset to the estimated angle.

8. The method as claimed by claim 1 , wherein determining the second offset comprises:

determining a type of the translational movement of the capturing apparatus based on the at least one translational apparatus motion parameter,

estimating an angle of each of the at least one audio signal source location relative to the capturing apparatus following the translational movement, and

calculating, for each of the at least one audio signal source location, the second offset based on the estimated angle and the type of translational movement.

9. The method as claimed by claim 8 , wherein compensating for the translational movement comprises adjusting the estimated angle of each of the at least one audio signal source location by the respective second offset.

10. The method as claimed by claim 1 , further comprising synthesizing the stabilized spatial audio signal using a head related transfer function.

11. The method of claim 1 , wherein:

the first offset is a constant offset and the second offset is a non-linear offset.

12. The method of claim 1 , further comprising:

capturing at least one further video image at another time instance;

determining at least one further video image motion value from the at least one further video image and at least one previously captured video image;

changing the first offset and/or the second offset based at least partially on the at least one further video image motion value.

13. An apparatus comprising at least one processor and at least one memory including computer code for one or more programs, the at least one memory and the computer code configured to with the at least one processor cause the apparatus at least to:

capture, by the apparatus, at least two video images at different time instances and at least one spatial audio signal, wherein capture of the at least one spatial audio signal comprises capture of at least one audio signal and determining, from the captured at least one audio signal, at least one audio signal source location relative to the apparatus;

determine from the at least two video images a video image motion value;

derive, based at least partially on the video image motion value, at least one of:

at least one rotational apparatus motion parameter, and

at least one translational apparatus motion parameter;

determine at least one of: a first offset based on the at least one rotational apparatus motion parameter and a second offset based on the at least one translational apparatus motion parameter; and

stabilize the captured spatial audio signal based at least partially on at least one of:

compensating for rotational movement of the capturing apparatus based on the first offset, and

compensating for translational movement of the capturing apparatus based on the second offset.

14. The apparatus as claimed in claim 13 , wherein the video image motion value is determined further causes the apparatus to:

determine at least two local motion values; and

combine the at least two local motion values to generate the video image motion value.

15. The apparatus as claimed in claim 13 , wherein the apparatus is caused to stabilize the spatial audio signal further causes the apparatus to apply the first offset and/or the second offset to the at least one audio signal source location relative to the apparatus.

16. The apparatus as claimed in claim 13 , wherein the at least one rotational apparatus motion parameter and the at least one translational apparatus motion parameter are derived further causes the apparatus to filter the at least one rotational apparatus motion parameter and the at least one translational apparatus motion parameter to remove higher frequency values.

17. The apparatus as claimed in claim 16 , wherein the apparatus is caused to determine unintentional movement of the apparatus based on at least one of:

the at least one rotational apparatus motion parameter, and

the at least one translational apparatus motion parameter,

wherein stabilizing the spatial audio signal comprises compensating for the determined unintentional movement.

18. The apparatus as claimed in claim 13 , wherein determining the first offset comprises estimating an amount of the rotational movement of the apparatus based on the at least one rotational apparatus motion parameter, and estimating an angle of the at least one audio signal source location relative to the apparatus following the rotational movement.

19. The apparatus as claimed in claim 18 , wherein compensating for the rotational movement comprises applying the first offset to the estimated angle of the at least one audio signal source location.

20. The apparatus as claimed by claim 13 , wherein determining the second offset comprises:

determining a type of the translational movement of the apparatus based on the at least one translational apparatus motion parameter,

estimating an angle of each of the at least one audio signal source location relative to the apparatus following the translational movement, and

calculating the second offset for each of the at least one audio signal source location based on the estimated angle and the type of translational movement.

21. The apparatus as claimed by claim 20 , wherein compensating for the translational movement comprises adjusting the estimated angle of each of the at least one audio signal source location by the respective second offset.

22. The apparatus as claimed by claim 13 , wherein the apparatus is caused to synthesize the stabilized spatial audio signal using a head related transfer function.

23. The apparatus of claim 13 , wherein the at least one memory and the computer code are configured to, with the at least one processor, cause the apparatus to:

capture at least one further video image at another time instance;

determine at least one further video image motion value from the at least one further video image and at least one previously captured video image;

change the first offset and/or the second offset based at least partially on the at least one further video image motion value.

24. A non-transitory computer-readable medium comprising computer program code that when executed by a computer causes the computer to:

capture at least two video images at different time instances and at least one spatial audio signal, wherein capture of the at least one spatial audio signal comprises capture of at least one audio signal and determine from the captured at least one audio signal at least one audio signal source location relative to an apparatus;

derive at least one of:

at least one rotational apparatus motion parameter, and

at least one translational apparatus motion parameter;

determine from the at least two video images a video image motion value; and

stabilize the captured spatial audio signal based at least partially on at least one of:

compensating for rotational movement of the apparatus based on a first offset, and

compensating for translational movement of the apparatus based on a second offset; and wherein the apparatus motion determiner is configured to derive the at least one rotational apparatus motion parameter and the at least one translational apparatus motion parameter based at least partially on the video image motion value.

25. The non-transitory computer-readable medium as claimed in claim 24 , wherein the computer program code causes the computer to:

determine at least two local motion values; and

combine the at least two local motion values to generate the video image motion value.

26. The non-transitory computer-readable medium as claimed in claim 24 , wherein computer program code causes the computer to apply the first offset and/or the second offset to the at least one audio signal source location relative to the apparatus.

27. The non-transitory computer-readable medium as claimed in claim 24 , wherein the computer program code causes the computer to filter the at least one rotational apparatus motion parameter and the at least one translational apparatus motion parameter to remove lower frequency values.