v10/internal/design/spf/features/5.1-surround-selection.md

status, date, definition

status	date	definition
draft	2026-05-20	technical

5.1 surround selection

Select an audio rendition the browser can decode while respecting the user's channel preference and preserving a stereo fallback.

Proposed direction

• Model channel count and codec as track capabilities, not language identity.
• Filter unsupported renditions before applying a preference for surround or stereo.
• Reuse the normal audio-track switch and buffer-flush path.
• Keep automatic device-output detection out of the first implementation.

Before implementation

Define the browser capability test, fallback order, and behavior when a midstream switch requires a codec change. Verify stereo-only, surround-capable, and misdeclared manifests.

Related

Capability probing and multi-language audio.