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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.

Here is the command and output:

ffmpeg -f dshow -list_devices true -i dummy -hide_banner
[dshow @ 0000000004efa5a0] DirectShow video devices (some may be both video and audio devices)
[dshow @ 0000000004efa5a0]  "Integrated Webcam"
[dshow @ 0000000004efa5a0]     Alternative name "@device_pnp_\\?\usb#vid_0c45&pid_641d&mi_00#7&11c87d18&0&0000#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\global"
[dshow @ 0000000004efa5a0]  "Decklink Video Capture"
[dshow @ 0000000004efa5a0]     Alternative name "@device_sw_{860BB310-5D01-11D0-BD3B-00A0C911CE86}\{44A8B5C7-13B6-4211-BD40-35B629D9E6DF}"
[dshow @ 0000000004efa5a0] DirectShow audio devices
[dshow @ 0000000004efa5a0]  "Microphone (2- High Definition Audio Device)"
[dshow @ 0000000004efa5a0]     Alternative name "@device_cm_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\wave_{11A03288-DE6D-4A21-A66E-DC9303E838FA}"
[dshow @ 0000000004efa5a0]  "Decklink Audio Capture"
[dshow @ 0000000004efa5a0]     Alternative name "@device_sw_{33D9A762-90C8-11D0-BD43-00A0C911CE86}\{AAA22F7E-5AA0-49D9-8C8D-B52B1AA92EB7}"
dummy: Immediate exit requested

and when I use "Decklink Audio Capture" to identify its options, here is the output:

ffmpeg -f dshow -list_options true -i video="Decklink Video Capture" -hide_banner
[dshow @ 000000000388a660] Unable to BindToObject for Decklink Video Capture
[dshow @ 000000000388a660] Could not find video device with name [Decklink Video Capture] among source devices of type video.
video=Decklink Video Capture: Input/output error
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3
  • Which binary are you using?
    – Gyan
    Mar 14, 2016 at 14:33
  • Did you tried it with the UUID? ffmpeg -f dshow -list_options true -i video=@device_sw_{860BB310-5D01-11D0-BD3B-00A0C911CE86}\{44A8B5C7-13B6-4211-BD40-35B629D9E6DF} Also, are you sure that you installed the blackmagic drivers?
    – Gergely Lukacsy
    May 20, 2016 at 7:55
  • @Mulvya I used static builds which are downloadable on link. @ Gergely Lukacsy I tried UUID of devices and result is the same. I also installed blackmagic drives because I can use it by MXPTiny as i mentioned in my question !
    – Dave_A
    Jun 11, 2016 at 4:32

2 Answers 2

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I know this is pretty old BUT as far as I know ffmpeg and Blackmagic Gear, you will have to set your input options according to the Stream it gets from the H-264 encoder.

So you need to tell ffmpeg that it gets H-264 encoded video and AAC encoded audio - then it should work.

This is not an issue with the DeckLink cards as they output raw video data. You might give it a shot...

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1
  • As far as I know, there in no direct support for BM H264Pro in ffmpeg "decklink" input device. They just support decklink pci cards with raw video production. I should first retrieve H264 output in some way the pipe it to ffmpeg for processing and transcoding.
    – Dave_A
    Aug 11, 2016 at 7:18
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It seems that Ffmpeg has a dedicated input mechanism for decklink devices, maybe give that a shot?

https://www.ffmpeg.org/ffmpeg-devices.html#decklink

Sounds as if it might be necessary to recompile Ffmpeg with decklink support though.

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2
  • Also see this thread where someone mentions you need to additionally specify the exact input format since it doesn't seem to be auto detected: ffmpeg.zeranoe.com/forum/viewtopic.php?t=1126
    – Hans Meiser
    Mar 14, 2016 at 14:02
  • I will try to compile last ffmpeg version with decklink support but all current static versions have(support) this option now. I also tried the link you mentioned and there was a compiled version here but the result is same as before.
    – Dave_A
    Jun 11, 2016 at 4:59

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