Is Black-Magic Support Close Caption?

Ask software engineering and SDK questions for developers working on Mac OS X, Windows or Linux.
  • Author
  • Message
Offline

pankajMahan

  • Posts: 3
  • Joined: Thu Apr 26, 2018 6:27 am
  • Real Name: Pankaj Kumar

Is Black-Magic Support Close Caption?

PostThu Apr 26, 2018 6:38 am

Hi,

Do Blackmagic provide any API in their development SDK to pass close caption alongside video or any other API to burn the close-Captions in the video? I'm using C++ develpment SDK of Blackmagic.

Thanks,
Pankaj Kumar
Offline

Cameron Nichols

Blackmagic Design

  • Posts: 442
  • Joined: Mon Sep 04, 2017 4:05 am

Re: Is Black-Magic Support Close Caption?

PostFri Apr 27, 2018 3:50 am

Hi Panjak,

Yes, it is possible to embed Closed Caption (CEA708), encoded as SMPTE 292M packets as VANC output.

Refer to:
  • DeckLink SDK Manual - 2.4.7.2 VANC Output high level overview
  • ClosedCaptions SDK sample (Mac/Win/Linux)
Regards
Cameron
Offline

pankajMahan

  • Posts: 3
  • Joined: Thu Apr 26, 2018 6:27 am
  • Real Name: Pankaj Kumar

Re: Is Black-Magic Support Close Caption?

PostMon Apr 30, 2018 6:51 am

Thanks, Cameron
Offline

pankajMahan

  • Posts: 3
  • Joined: Thu Apr 26, 2018 6:27 am
  • Real Name: Pankaj Kumar

Re: Is Black-Magic Support Close Caption?

PostWed May 02, 2018 6:05 am

Hi Cameron,

I tried ClosedCaptions SDK sample for windows. I'm using a black-magic 4K card and 4k Samsung monitor and they are connected via HDMI port. But problem is that I didn't see any closed caption on the monitor. It just shows three blue frames.

Any kind of help will be appreciated.

Thanks,
Pankaj Kumar
Offline

Cameron Nichols

Blackmagic Design

  • Posts: 442
  • Joined: Mon Sep 04, 2017 4:05 am

Re: Is Black-Magic Support Close Caption?

PostFri May 04, 2018 1:41 am

Hi Panjak,

Let me elaborate on my previous post. Closed Captions is supported on SDI as it follows the SMPTE ST 334 specification for transmitting in VANC for HD, or LINE21 for NTSC.

There is no equivalent standard for transmitting Closed Captions over HDMI, it is the responsibility of the content providers to decode Closed Captions within the Set Top Box.

Regards
Cameron
Offline

asperi

  • Posts: 16
  • Joined: Sat Nov 27, 2021 5:59 pm
  • Real Name: Matt Cavis

Re: Is Black-Magic Support Close Caption?

PostWed Dec 01, 2021 5:31 am

Is there any real way to see 608 or 708 captions out Decklink SDI? I have tried Resolve, CasparCG, Vmix, OBS, FFMPEG- successfully playing my mpeg-2 files out the SDI but never showing captions. Cannot get the SDK samples to play mpeg-2, the files have embedded 608 and 708 captions. Viewing on an SDI broadcast monitor, captions display fine on the monitor from the SDI out of a different card vender. Any guidance of how to make it work would be great, thanks!
Offline

asperi

  • Posts: 16
  • Joined: Sat Nov 27, 2021 5:59 pm
  • Real Name: Matt Cavis

Re: Is Black-Magic Support Close Caption?

PostThu Dec 02, 2021 4:12 pm

Tried Blackmagic DeckLink SDK 12.2\Win\Samples\bin\ClosedCaptions.exe
CMD window comes up - says: Playing.. Press <Return> to exit. Shows just a blue screen on the monitor. Viewing on a professional broadcast SDI monitor- JVC DT-V17G1Z, this monitor shows captions when playing out a different venders card.

In the ClosedCaptions.exe, where/ how do I specify what file to play? What even is this sample doing?

Thanks!

Return to Software Developers

Who is online

Users browsing this forum: No registered users and 18 guests