[FFmpeg-user] Using ffmpeg to stream to or from Blackmagic Decklink Card

Reuben Martin reuben.m at gmail.com
Tue Jun 14 05:49:44 CEST 2016

On Tuesday, June 14, 2016 1:46:52 AM CDT davood afshari wrote:
> Hello,
> I want to use blackmagic cards with ffmpeg to stream their input but there
> is a problem.
> When I use "H264 Pro" Encoder as a "decklink" or "dshow" input, I see this
> error in command line output of ffmpeg. Device is ok and I can Use it with
> other applications like MXPTiny or MXLight.

Decklink cards and the "H264 Pro" encoder box are two completely different 
things. Decklink provides uncompressed audio-video source and / or sink, while 
the little encoder box provides h264 + aac encoded video and audio in a mpeg2 
transport stream format. Just because blackmagic design supports both products 
in the same package bundle does not mean their internals are in any way 

Your encoder box will not work using the decklink API. You might be able to 
find some way to route the transport stream to ffmpeg via directshow somehow. 
I'm not sure if that's possible though

I've piped output from the encoder box to ffmpeg before using bmd-tools.


However that is Linux only and will not work on windows.

I've used Decklink card with ffmpeg for for streaming since about 2011 or 2012 
from an SDI source and it works quite well. I've also tried using that h264 
encoder box one time and I will warn you now: it is really awful. The quality 
looks like garbage, the bitrate is absurdly high, and the encoding has all 
sorts of errors. Despite the name, it is anything but "Pro".


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