scc
What is a .scc file?
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SCC (Scenarist Closed Captions, .scc) is the broadcast interchange format for CEA-608 captions. Each line is an SMPTE timecode followed by pairs of hexadecimal bytes that are the literal 608 control codes and characters, so caption positioning, roll-up versus pop-on style, and italics are all encoded as byte pairs rather than as markup. It is plain ASCII, but it is not human-readable prose.
How to use a .scc file
Use an example .scc file to test broadcast caption ingest, CEA-608 decoders, and conversion to SRT or WebVTT. It is the format that exposes decoders which assume captions are text — parity bits, double-byte control codes, and drop-frame timecodes all have to be handled.
Download example .scc files
- SCC — Broadcast CEA-608 CaptionsBroadcast closed captions as Scenarist SCC: SMPTE timecodes followed by hexadecimal CEA-608 byte pairs, with odd parity set on every byte as the standard requires. Uses pop-on mode — RCL to load, ENM to clear non-displayed memory, a preamble address code for row 15, the character pairs, then EOC to display. This is the fixture that exposes decoders which treat captions as text: the parity bits, the two-byte control codes and the frame-accurate timecodes all have to be handled.
- SCC — Intentionally Corrupt: Wrong Parity BytesAn intentionally corrupt SCC file whose first caption is valid but whose second carries byte pairs with the wrong parity. CEA-608 requires odd parity in bit 7 of every byte, and broadcast decoders use it to detect transmission errors. Tests whether a decoder checks parity at all, and whether it drops just the bad caption or the whole file.