ST2110OutputTtmlSender interface

ST 2110-43 TTML sender. Carries TTML2/IMSC1.2 caption documents over RFC 8759 on a dedicated RTP session at 90 kHz. Wire is fundamentally different from ST2110OutputAncillarySender (different SDP, different RFC) so this is its own sender shape.

codecs is the IMSC profile short code (e.g. "im2t" for IMSC1 Text profile, see https://www.w3.org/TR/ttml-profile-registry/) advertised via the SDP a=fmtp:<pt> codecs=<short> parameter — mandatory per RFC 8759 §11.2.

Signature:

export interface ST2110OutputTtmlSender

Properties

Property Type Description

Property	Type	Description
codecs	string	IMSC profile short code (`"im1t"`, `"im2t"`, etc.).
frameRate	{ frames: number; seconds: number; }	Pacing rate for MTL’s tasklet — typically the matching video session’s frame rate. Actual TTML emission rate is driven by upstream cue arrival, not by this field.
payloadType?	number	(Optional) Defaults to Norsk’s TTML default (114).
rtpRingSize?	number	(Optional) RTP ring size; must be a power of two. Defaults to 1024 (plenty for typical TTML cue rates, which are 1s+ apart).
ssrc?	number	(Optional)
type	"ttml"

codecs

string

IMSC profile short code ("im1t", "im2t", etc.).

frameRate

{ frames: number; seconds: number; }

Pacing rate for MTL’s tasklet — typically the matching video session’s frame rate. Actual TTML emission rate is driven by upstream cue arrival, not by this field.

payloadType?

number

(Optional) Defaults to Norsk’s TTML default (114).

rtpRingSize?

number

(Optional) RTP ring size; must be a power of two. Defaults to 1024 (plenty for typical TTML cue rates, which are 1s+ apart).

ssrc?

number

(Optional)

type

"ttml"