Closed Captions Format Definitions:
The Encoding.com API makes it really simple to extract, inject, mux or copy closed captions of any kind for distribution to most mobile digital video platforms. As we work together, please feel free to reach out to us through our helpdesk or via live chat to get answers to questions. You can also get direct access to these features for free on our introductory developer accounts. Just sign up for a free 1GB account.
SCC files contains captions in Scenarist Closed Caption format. An SCC sidecar file contains timing information with corresponding text data. SCC files are to the video files editors use as analog and digital captions are to the video files that play on the flatscreen in your living room. They can be shared easily.
SRT is the simplest sidecar format for subtitles. Most software video players (Mac, PC, iOS & Android) support SRT sidecars natively. Pirates, startups and small businesses often use SubRip to create SRT files. We don’t judge them.
DFXP is a sidecar format for subtitle exchange and distribution to HTML5 media players defined by the W3C. DFXP stands for Distribution Format Exchange Profile. Not to put too fine a point on it, but SCC is more common among editors and SRT is much more reliable across devices and players.
SAMI (Synchronized Accessible Media Interchange) is a subset of HTML & CSS developed by Microsoft. Many Windows-based video players support SAMI. When an SRT or SCC sidecar isn’t available, a SAMI file may be useful.
3GPP Timed Text is specified in 3GPP TS 26.245 and is the global timed text standard for all 3G multimedia services. This format is the model for MPEG-4 Part 17 (aka MPEG-4 Timed Text) as well. MPEG-4 Part 17 is the subtitle format for MPEG-4, published as ISO/IEC 14496-17 in 2006. The iOS native player supports 3GPP TT in 3GP and MPEG-4 TT in MP4 files.
CEA-608 & CEA-708 standards are the official formats for closed captions.