Not really anything regarding stereo, but how to digitally recreate a 3D space and provide the resultant acoustic signature to stereo headphones? So, you could digitally model Carnegie Hall, or a warehouse, or a coffee shop, and if you know the locations of your point sources of audio you can then create what the room would sound like based on a given listener location and orientation? It sounds (a bit like) raytracing for audio, with the format allowing a standardized way to define the space.
Yes? No? For once, I think we actually need an *article* to go with this abstract, or at least a Bennet Haselton-style rant* as the summary.
*except factual, useful, and correct.
Kind of... You know how, even though you only have two ears, you can still determine whether a sound is coming from in front of you, behind you, above you, below you, etc.? You don't need 5 ears or 7 ears or whatever surround-sound standard you think of, and yet you still get a great 3D image. It has to do with some complicated math our brains are instinctively doing, measuring the interaural phase differences of low frequency signals received at each ear, and interaural timing and amplitude differences of high frequency signals. A signal from your right that gets to your right ear has to travel an additional foot and a half or so to get to your left ear, and that results in a phase difference for a signal with a long wavelength (say, below around 800 Hz) or a time and amplitude difference for signals with shorter wavelengths.
Additionally, your ears are not symmetrical, but have a small reflector at the front, a curved reflector along the top and back, etc., and these reflectors have specific reflective and absorptive bandwidths, so signals coming from different directions (above you, below you, etc.) are filtered in slightly different ways.
All of these features make up the head-related transfer function (HRTF) that acts as a filter on a signal based on its frequency and 3-dimensional position around your head.
As an aside, binaural recordings are typically done with things that look like headphones, but are actually microphones placed very close to the engineer's ears, so that the audio they pick up is affected by the HRTF. When you play the recording back over headphones, you get incredible 3D audio. And Neumann makes the KU 100 head-on-a-stick binaural microphone that actually has rubbery ears and microphones placed where eardrums would be.
This standard defines ways to store and process the HRTF so that recordings can be decoded by binaural processors for playback in earbuds or headphones. Importantly, it allows a recording to be stored in a format capable of multiple ways of decoding, so that you can have one track that you can play in surround sound from your speakers, or load up on your phone and play through ear buds, and still get a great 3D environment (binaural recordings don't work effectively through speakers, and surround sound collapses down to stereo through ear buds; this allows one file to play on both).