During last year's WWDC keynote, Apple's SVP (SVP) of software engineering, Craig Federighi, introduced Spatial Audio for FaceTime which can be seen in the video snippet below.

Today the U.S. Patent and Trademark Office officially granted Apple a patent for this feature, making it yet another patent fulfilled.

However, there seems to be an added dimension to their invention that allows a couple, for example, being in a grocery store. When the couple FaceTime each other, while in different parts of the store, the spatial audio will direct the couple to hear areas of the store each are in, like the milk or frozen food aisle.  Meaning, the spatial audio goes beyond the FaceTime UI of the iPhone and will allow a user with AirPods to audibly sense the area of the store that the other FaceTime participant is speaking from.  Of course, that would be great to use at a concert or sporting event when you're trying find your friends. That's a pretty cool application for spatial audio. 

In Apple's granted patent summary, they note that there is a need for audio output devices and in some embodiments associated electronic devices with improved methods and interfaces for spatializing audio during communication sessions and communication session that include a visual component (e.g., a video call). Such methods and interfaces optionally complement or replace conventional methods for stereo and mono audio output modes in communication sessions. Such methods and interfaces reduce the number, extent, and/or nature of the inputs from a user and produce a more efficient human-machine interface. For battery-operated systems and devices, such methods and interfaces conserve power and increase the time between battery charges.

Apple's patent FIG. 10D below illustrates how prominence of a participant may alternatively or in addition be indicated by the proximity of a participant's video representation to a predefined position in user interface #500, such as a center position. In FIG. 10D, participant three is the most active participant as indicated in activity chart #1006. Accordingly, video representation #1014 of participant three is displayed closest to the center of in-focus region #1002 (e.g., as compared to video representations #1001, #1003, and #1018 of participants one, two, and four, respectively) and overlapping on top of video representations (1001, 1003, and 1018) of participants one, two, and four, respectively, in user interface #500.

Apple's patent FIG. 6G below is a more advanced example. It illustrates audio properties that change when the users are at a large distance away from each other in a store, for example (e.g., and typically, out of visual contact with each other). In this example, because user #636 has moved further away from user #634 than was the case in FIG. 6F. This change in position of user 636 is indicated by mini-map #642 in FIG. 6G, which shows second user's position #640 separated further from first user's position #638 than in FIG. 6F.

The mini-map in FIG. 6G also illustrates audio waves (e.g., waves #660 and waves #662) emanating from the simulated spatial location of each user's position (e.g., first user's position #638 and second user's position #640), and the audio waves locations have been updated (relative to the ones shown in FIG. 6F) to reflect the change in position of the earbuds in physical space.

For more details, review Apple's granted patent US 11523243 B2 which was officially filed in September 2021, three months after introducing the initial phase of this invention at WWDC21.