Problems receiving VideoInputFrameArrived callback

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  • Joined: Thu Mar 28, 2019 1:24 pm
  • Real Name: Marco Kaldenbach

Problems receiving VideoInputFrameArrived callback

PostThu Mar 28, 2019 1:55 pm


While developing an application (under Linux with the C++ Software Developers Kit) to pass through video frames, receiving from a BlackMagic DeckLink Quad 4 card, I have a weird problem. The problem I have is that sometimes I'm not receiving callbacks from an input (I use 6 inputs and 2 outputs). The problem occurs, most of the times, only on 1 input but sometimes on multiple inputs at the same time. The input number which is not returning the callback is different every time. When an input does not return a callback it will not return a callback until I kill the whole application and restart it. After restarting the application it works either just fine or an other input does not return its callback.
I use the VideoInputFrameArrived callback to pass the video frame to the output. It looks like something goes wrong while initializing the input. However I logged every value I set and all the values and response codes are the same for all of the inputs during initialization.
If I log the available video frame count and the audio sample frame count from the IDeckLinkInput object, which is having troubles giving a callback, I receive this:
AvailableVideoFrameCount = 0
AvailableAudioSampleFrameCount = 48000
So it does look like I am receiving audio samples.

I enable both Audio and Video. If the input gives a callback as expected, then everything works totally fine.

Do you have any idea how it comes that the inputs are not giving a callback?

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