When a Multivariant Playlist declares its closed-caption renditions with
EXT-X-MEDIA:TYPE=CLOSED-CAPTIONS, a player should present only the
INSTREAM-IDs it names. hls.js instead surfaces every 608 channel that happens to carry
data. Both players below load the same stream from the same manifest; only the library differs.
Read the issue →
Caption tracks appear as the players decode 608 data, so give it a few seconds of playback. Click a chip to render that channel over the video. Red chips are channels the manifest never declared.
Gated on a new filterUndeclaredClosedCaptions config option (default true).
Playlists that declare no CLOSED-CAPTIONS renditions — and single Media Playlists, which cannot declare
any — keep the old behavior, so streams that rely on undeclared channels today are unaffected.