Apple wants to improve the audio of videos make with your iPhone and iPad. The company has filed for a patent (number 20200137489) for “spatially biased sound pickup for binaural video recording.”
In the patent filing, Apple notes that binaural recording of audio facilitates a means for full 3D sound capture–in other words, being able to reproduce the exact sound scene and giving the user a sensation of “being there.” This can be accomplished through spatial rendering of audio inputs using head related transfer functions (HRTF), which modifies a sound signal in order to induce the perception in a listener that the sound signal is originating from any point in space.
However, Apple says that while this approach is compelling for, for example, full virtual reality applications, in which a user can interact both visually and audibly in a virtual environment, in traditional video capture applications three dimensional sounds can distract the viewer from the screen. In contrast, monophonic or traditional stereophonic recordings may not provide a sufficient sense of immersion. Apple wants to change this
Here’s the (rather technical) summary of the patent filing: “A method for producing a target directivity function that includes a set of spatially biased HRTFs. A set of left ear and right ear head related transfer functions (HRTFs) are selected. The left ear and right ear head HRTFs are multiplied with an on-camera emphasis function (OCE), to produce the spatially biased HRTFs. The OCE may be designed to shape the sound profile of the HRTFs to provide emphasis in a desired location or direction that is a function of the specific orientation of the device as it is being used to make a video recording.”