opus_custom(3) on Linux
The text 7e1a55b5921c, as Debian 13 (Trixie) shipped it. The page shows this text now.
Opus Custom - Opus Custom is an optional part of the Opus specification and reference implementation which uses a distinct API from the regular API and supports frame sizes that are not normally supported. Use of Opus Custom is discouraged for all but very special applications for which a frame size different from 2.5, 5, 10, or 20 ms is needed (for either complexity or latency reasons) and where interoperability is less important.