Head motion prediction for spatial audio applications

1. A method comprising:

obtaining, using one or more processors, motion data from a source device and a headset;

obtaining, using the one or more processors, transmission delays from a wireless stack of the source;

estimating, using the one or more processors, relative motion from the relative source device and headset motion data;

calculating, using the one or more processors, a first derivative of the relative motion data;

calculating, using the one or more processors, a second derivative of the filtered relative motion data;

forward predicting, using the one or more processors, the estimated relative motion over the time delays using the first derivative and second derivative of relative motion;

determining, using a head tracker, a head pose of a user based on the forward predicted relative motion data; and

rendering, using the one or more processors and the head pose, spatial audio for playback on the headset.

2. The method of claim 1 , wherein rendering, using the one or more processors and the head pose, spatial audio for playback on the headset comprises:

rendering audio channels in an ambience bed of a three-dimensional virtual auditory space, such that a center channel of the audio channels is aligned with a boresight vector that originates from a headset reference frame and terminates at a source device reference frame, wherein the center channel is aligned with boresight vector by rotating a reference frame for the ambience bed to align the center channel with boresight vector, and wherein the boresight indicates a relative position between the source device and the headset.

3. The method of claim 1 , wherein the motion data is obtained over a Bluetooth™ communication channel between the headset and the source device.

4. The method of claim 1 , wherein the source device is a mobile device are configured to present visual content synchronized with spatial audio played through the headset.

5. The method of claim 1 , wherein the time delays includes a return delay from the source device to the headset that is measured by a wireless communication stack on the headset and sent back to the source device with the headset motion data.

6. The method of claim 5 , wherein time delays include a first time delay to decode packets carrying the motion data and a second time delay to access and read buffers storing the motion data.

7. The method of claim 5 , wherein the return delay is predicted or estimated based on an average of return time delays that are accumulated by at least one of the headset or the source device.

8. The method of claim 1 , further comprising:

filtering, using the one or more processors, the first derivative of the relative motion data to remove outlier data.

9. The method of claim 1 , wherein the filtering includes filtering using a median filter.

10. The method of claim 1 , wherein the motion data includes relative position data and rotation data, the first derivative of the relative position is relative velocity, the first derivative of the rotation data is rotation rate, the second derivative of relative velocity is relative acceleration and the second derivative of rotation rate is rotational acceleration.

11. A system comprising:

one or more processors;

memory storing instructions that when executed by the one or more processors, cause the one or more processors to perform operations comprising:

obtaining motion data from a source device and a headset;

obtaining transmission delays from a wireless stack of the source;

estimating relative motion from the relative source device and headset motion data;

calculating a first derivative of the relative motion data;

calculating a second derivative of the filtered relative motion data;

forward predicting the estimated relative motion over the time delays using the first derivative and second derivative of relative motion;

determining, using a head tracker, a head pose of a user based on the forward predicted relative motion data; and

rendering, using the head pose, spatial audio for playback on the headset.

12. The system of claim 11 , wherein rendering, using the one or more processors and the head pose, spatial audio for playback on the headset comprises:

rendering audio channels in an ambience bed of a three-dimensional virtual auditory space, such that a center channel of the audio channels is aligned with a boresight vector that originates from a headset reference frame and terminates at a source device reference frame, wherein the center channel is aligned with boresight vector by rotating a reference frame for the ambience bed to align the center channel with boresight vector, and wherein the boresight indicates a relative position between the source device and the headset.

13. The system of claim 11 , wherein the motion data is obtained over a Bluetooth™ communication channel between the headset and the source device.

14. The system of claim 11 , wherein the source device is a mobile device are configured to present visual content synchronized with spatial audio played through the headset.

15. The system of claim 11 , wherein the time delays includes a return delay from the source device to the headset that is measured by a wireless communication stack on the headset and sent back to the source device with the headset motion data.

16. The system of claim 15 , wherein time delays include a first time delay to decode packets carrying the motion data and a second time delay to access and read buffers storing the motion data.

17. The system of claim 15 , wherein the return delay is predicted or estimated based on an average of return time delays that are accumulated by at least one of the headset or the source device.

18. The system of claim 11 , further comprising:

filtering, using the one or more processors, the first derivative of the relative motion data to remove outlier data.

19. The system of claim 18 , wherein the filtering includes filtering using a median filter.

20. The system of claim 11 , wherein the motion data includes relative position data and rotation data, the first derivative of the relative position is relative velocity, the first derivative of the rotation data is rotation rate, the second derivative of relative velocity is relative acceleration and the second derivative of rotation rate is rotational acceleration.