Method

IMSC subtitle conformance

IMSC1 / IMSC1.1 subtitle conformance, W3C TTML2

What we measure and how

Parses IMSC1 (text profile, used by IMF and HbbTV) and IMSC1.1 (image profile) timed-text documents and validates structure, region / style references, image resource resolution, and the timing model (tick / frame / clock-time metrics with drop-frame awareness). A rules engine then applies the active delivery profile (e.g. Netflix) to enforce reading speed, line length, line count, region count, minimum cue duration and gap, and language tagging. Cross-checks reconcile cues against the CPL Subtitle Sequence window and MXF subtitle descriptor. Findings are emitted as namespaced `imsc.<area>.<rule>` rule IDs.

Provenance

Standards

W3C TTML2 · W3C IMSC1 · W3C IMSC1.1 · SMPTE ST 2067-2 (subtitle sequence)

Method identifier: imsc_subtitle_conformance