Closed captions support in MPlatform

With its most recent update, MPlatform supports capturing of CEA-608 (analogue) and CEA-708 (digital) closed captions - in addition to playback, which has been available with Closed Captions lib earlier.

As closed captioning (or CC) is an important part of broadcast TV and is mandatory in the United States, Canada, Europe, Asia and Latin America, we have had multiple requests from customers to have this feature fully supported.

So far, we have tested the playback and ingest of CC data with Blackmagic devices. Most of the cards in the DeckLink family do support SDI metadata - this includes the new DeckLink Studio 4K and DeckLink SDI 4K.


Today, MPlatform supports the playback of CEA-608 (NTSC) and CEA-708 (digital television) closed captions data stored in a number of ways, such as in MPEG user data (MPEG TS, MPEG PS, MPEG-4, MXF, GXF), a separate track in .MOV and .MP4 files and as VBI or VANC data in .MXF and .LXF files.

Decoder lib and Closed Captions lib are required for playback of closed captions data. More technical information:


The MWriter object will automatically capture CC data into an external file, if it is available in the stream. CEA-608 data is captured in .SCC files. For CEA-708 we have, for now, implemented a custom file format (.ACC). If you have any thoughts or suggestions about a file format to use (.MCC maybe?), please let us know.

Encoder lib and Closed Captions lib are needed for the CC capturing use case. More information with technical details: