Binaural rendering produces a two-channel signal specifically for headphones, designed to recreate the directional cues a listener would experience from real sources in space. It works by filtering each virtual sound through the HRTFs for its direction, so the brain hears the time, level, and spectral differences that say 'this is above me and to the left'. Done well, sources seem to exist around and outside the head — externalization — rather than stuck between the ears as ordinary stereo does. It is how object and scene-based formats (Dolby Atmos, Ambisonics) collapse to earbuds, and adding head tracking, so the scene stays fixed as you turn, makes the illusion markedly more convincing.
The book · Volume 5 of 7
Audio for Video: A Complete Guide to Sound in Video Products: From Jitter Buffers and Lip Sync to Atmos, Quality Metrics, and Neural Codecs
Binaural rendering is how most people will hear spatial audio, on ordinary headphones, and generic HRTFs make it sound vague for many listeners. Volume 5 covers binaural rendering in detail within spatial audio: HRTF, ambisonics, Dolby Atmos, object-based sound and keeping the rendered scene in sync with picture. Written by Nikolay Sapunov, CEO at Fora Soft.
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