Spatial Audio Online
A platform developed by the Lithuanian Academy of Music and Theatre (LMTA) for sharing, streaming, and archiving spatial audio compositions in Higher-Order Ambisonics and other immersive formats — rendered live in the browser with real-time binaural decoding.
Binaural Rendering
HOA signals up to 4th-order (25 channels) are decoded to binaural stereo in real time using HRIR convolution through the Web Audio API. No special hardware required beyond headphones.
Head Tracking
Gyroscope-driven head tracking works on iOS and Android, and via mouse-drag on desktop. The soundfield rotates naturally as you move your head, giving a genuine immersive experience.
360° Video
Pieces can include equirectangular 360° video. On desktop, H.264 MP4 is hardware-decoded inside a WebXR-capable equirectangular sphere. On iOS and Android, the same file is rendered via Three.js with gyroscope synchronisation.
Venue Archive
Spaces and speaker layouts are catalogued with interactive 3D visualisations. Venues can attach their Ambisonics Impulse Responses for acoustic room simulation.
Articles
A journal-like article system lets artists, composers, and researchers publish texts with rich media, embedded pieces, PDF attachments, and editorial review.
Research Archive
The platform serves as a documentation archive for LMTA's activities in spatial and immersive audio — artist profiles, academic outputs, and venue records preserved in one place.
How the audio pipeline works
Uploaded WAV files (up to 25-channel HOA) are processed server-side: normalised, then transcoded via ffmpeg into an Opus/WebM DASH stream for desktop and Android, a 4-channel AAC M4A for iOS head tracking (FOA path), and a stereo AAC M4A as a universal fallback. The browser-side HOA rendering stack (hoast360) loads HRIR filter banks, applies an Ambisonics rotation matrix based on head/viewport orientation, and decodes to binaural stereo using convolution nodes in the Web Audio API.
Funded by
