My company currently uses many different Black Magic cards including but not limited to the Decklink SDI and the Decklink HD Extreme.
Please note that in this article I simplified the terms to 608 or 708 captions, but you will often see these terms referred to as EIA-608 or EIA-708 after its developer Electronic Industries Alliance. A LITTLE BIT ABOUT 608 CAPTIONS (LINE 21 CAPTIONS).
Eia-608/708
We need to be able to pass EIA-608 closed captions through the card, into an SDI to Analog mini converter and finally into a TV via the AV video port.- Closed Captions - Displays EIA-608 708 and Tele Text Captions for LV5350 Software Leader LV5350-SER21 is a software option that enables CLOSED CAPTIONS - Displays EIA-608, 708 and TELETEXT captions for the LV5350 waveform monitor.
- Demuxing of the 608 Caption Caption Data from 436M was added with commit ef23ed6fe96e4ec8d11c82f8be19a2877f9737ee. Description is that the 608 Data is extracted but I believe it may be the 608+708. If the resulting caption data can be passed through to MPEG-2 and x264 encoders as ASTC A/53 caption data then that would meet this feature request.
- EIA-608 are standard CC subtitles with the black bar background, while EIA-708 are typically SDH.
- EIA-608 CEA-708 EIA-708 If your input captions have both embedded captions and SCTE-20 captions, and you want both types in your outputs, set up separate input captions selectors for the SCTE-20 and the embedded captions tracks.
What's Closed Captions Eia 608 & 708
In an attempt to understand the decklink SDK and EIA-608 closed captions I changed the code in the VancOutput.cpp. Since this is the official SDK I feel it should serve as a good baseline for my development, however I have had no success displaying the closed captions on the TV.
For our software to continue to use decklink devices it is of the highest priority that I get this to work. Once I can prove that the VancOutput example works with 608 closed captions I can move on to the real coded solution.
I have uploaded a copy of the code file, according to the email support I received from Blackmagic developer support the code looks correct however it still continues to only display a blue screen without subtitles.
I have tried every closed caption channel, CC 1-4 and Text 1-4, without any luck.
Am I missing some important key factor?
Regards,
Nick Hanshaw
Comments are closed.