Embed Dolby Digital (AC3) using Decklink SDK

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Eric Lariviere

  • Posts: 8
  • Joined: Wed May 25, 2016 6:51 pm

Embed Dolby Digital (AC3) using Decklink SDK

PostMon Sep 26, 2016 10:05 pm

I would like to know if it is possible to embed Dolby Digital (AC3) and/or Dolby E on Decklink Duo 2 using the SDK?

BMDAudioFormat enum currently only has bmdAudioFormatPCM, but would the card actually transform the signal if something else than PCM is scheduled instead?

If it is possible, do you have any recommendations on how to schedule frames from my AC3 stream?

Thanks in advance!

Waqqas Sharif

Blackmagic Design

  • Posts: 21
  • Joined: Tue Oct 04, 2016 1:47 am

Re: Embed Dolby Digital (AC3) using Decklink SDK

PostWed Oct 05, 2016 11:04 pm

Hello Eric,

The answer is no as currently (Desktop Video / DecLink API) only supports (48 KHz) audio (input / output) over PCM and there is no plan to add support for non-PCM audio (input / output) in near future.



  • Posts: 1
  • Joined: Tue Nov 07, 2017 12:08 am

Re: Embed Dolby Digital (AC3) using Decklink SDK

PostTue Nov 07, 2017 12:12 am

Hi, Waqqas

Is there any update on this?
Adding AC3 pass-through will significantly expand scenarios in which decklink cards could be used.


  • Posts: 3
  • Joined: Wed May 15, 2013 10:46 am

Re: Embed Dolby Digital (AC3) using Decklink SDK

PostWed Nov 29, 2017 12:10 am

Dolby E output should work - that's carried within regular 48kHz PCM audio streams. However you need to ensure a clean 24 bit (sometimes 20 bit?) path - anything that truncates to 16 bit will kill Dolby.

I've had no problems capturing or playing out Dolby E streams on a BlackMagic Decklink or Ultrastudio Express using third party NLEs (Avid MC and Prem Pro) Capture tools or Playout, but for a long time BlackMagic Media Express was 16 bit only for audio capture (though have a feeling this limitation may have gone)

See no reason why the SDK won't let you output Dolby E.

AC3 (i.e. Dolby Digital - such as is carried over HDMI) is a different kettle of fish. I've never encountered it in the SDI domain - only the HDMI one. (It would be very useful in that situation)

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