Discovers sidecar text tracks from an HLS multivariant playlist.
Per RFC 8216 §4.3.4.2, subtitle renditions are signaled with
EXT-X-MEDIA:TYPE=SUBTITLES and (when usable as sidecar) carry a URI
attribute pointing at a media playlist or, in the simplified single-file
case, a .vtt file directly.
Closed captions (TYPE=CLOSED-CAPTIONS) are intentionally excluded - they
are delivered in-band with the video stream and are surfaced by the browser
automatically, not through a sidecar fetch.
Discovers sidecar text tracks from an HLS multivariant playlist.
Per RFC 8216 §4.3.4.2, subtitle renditions are signaled with
EXT-X-MEDIA:TYPE=SUBTITLESand (when usable as sidecar) carry aURIattribute pointing at a media playlist or, in the simplified single-file case, a.vttfile directly.Closed captions (
TYPE=CLOSED-CAPTIONS) are intentionally excluded - they are delivered in-band with the video stream and are surfaced by the browser automatically, not through a sidecar fetch.