Intensity Pro Analog Audio Input is Not Working Without the Presence of any Analog Video Input

[Chad Pearson]

When you capture audio using the card are you also trying to capture video at the same time (ie through the HDMI or some other input)? Or are you just trying to use it as an audio capture device? In your Blackmagic control panel what is set for your Input Source? HDMI + Analog Audio, Composite + Analog Audio, Component + Analog Audio?

[Malik Yusuf]

No, we are not trying to capture the video (not through the HDMI/Composite/Component) in this case, we are trying only to capture the audio from our audio console through the analog RCA port of the Intensity Pro Card. In terms of ingesting/Capturing we are trying to use the BM Intensity Pro card as an audio capture device, not the video in this case.

Our Blackmagic Control Panel’s Input setting is set as “Composite + Analog Audio”. Even we have tried the “Component + Analog Audio” settings, but no input audio is found until I connect any composite or Component Y connection to the Green RCA Video input port.

So I think that the Intensity Pro Card is using the video signal to initiate the capture process, and if it can’t detect any video signal on its green video input port, it assumes that the ingest process is not required at all, which was not an issue when we were using our Matrox cards for such purpose. Thats the problem.

Chad Pearson, it would be great if you could point me some more hints, thanks.

[Ericbowen]

The Blackmagic cards function as a standalone audio output device but not an input device. The Blackmagic cards require a video signal to bring in the audio signal. If you just want an audio input then you require a real audio interface. I would suggest looking at the Steinberg UR22 or UR44. Both are USB audio interfaces with good quality A/D converters for the price.

Eric-ADK
Tech Manager
support@adkvideoediting.com

[Malik Yusuf]

Eric Bowen,
Now I know that you are absolutely right, The Blackmagic cards require a video signal to bring in the audio signal. So if I just want an audio input then I require a real audio interface. I think that’s the only option I should implement to solve this odd problem. I hate Blackmagic for this situation but the truth is unveiled at least. Thanks again.

[Jim Sustacek]

It shouldn’t need to be an analog video source — you can use HDMI video + Analog RCA audio too.

So, if your computer’s video card can output HDMI, you could send that into the Intensity Pro (might have to adjust the resolution to get it to work). You might have to use another output on your video card if you want to have a monitor connected (VGA? DVI?). Or if you have another Blackmagic device with an unused HDMI output, or any other HDMI output device, you could route that into the Intensity Pro too.

[Jimmy See]

Hi Eric

I realise this post is several years old now and also that you do not represent Blackmagic, but this is one of the few places around where the fact you pointed out, that blackmagic products do not support audio input without accompanying video input, is actually clearly stated.

I ask you, but I guess the internet in general and hopefully blackmagic can see this, WHY!? Is this a technical limitation of how the cards work or some kind of decision to deliberately restrict users in this fashion? It is actually really not made clear at all to people who are buying this product in any obvious way. I’ve actually looked and forum posts are the only place where I’ve seen this spelled out in black and white. If it is documented somewhere, it’s obscure enough that people are unlikely to discover it by chance and I could not find it even by looking. I can’t see the justification for making the products behave in this manner. I’m not aware of any blackmagic audio-only capture devices so it doesn’t seem like a cutthroat strategy to force people to buy two products, I can’t see it making much sense from a piracy prevention standpoint either if it’s somehow related to that. I thought perhaps they were trying to force people to purchase higher end models with the capability but this post https://forum.blackmagicdesign.com/viewtopic.php?f=3&t=32050 seems to imply that no blackmagic products will do it. Also if they did, surely they would be making sure people were well aware of the limitation/feature so that they could persuade people to buy their more expensive models which did have the functionality.

I discovered this limitation and stumbled on this thread trying to help a TV editor with their system. They wanted to record temporary narration with a microphone plugged in to a mixing deck going in their intensity pro 4k card. This, I suspect is a very common setup for broadcast editors, certainly it is the standard arrangement I’ve seen on older systems which used matrox hardware for I/O prior to blackmagic entering the market. We were left scratching our heads why this couldn’t work until finding this and some other forum posts reiterating this limitation, I found it nowhere on Blackmagic’s website or in the Blackmagic desktop video manual which appeared to be the only form of manual they offered for this hardware. It makes very little sense and I think if things HAVE to be this way, they could at least signpost this a lot earlier given many of their customers would likely be film and TV editors who will likely encounter this very situation.

[Chad Pearson]

This answer is a gross simplification of how device drivers work.

When you write a hardware driver for a specific operating system, like Windows or MacOS, you have to tell the operating system what type of device is at the other end of the connection. The operating system defines the possible choices, and the capabilities of each choice. Now, Blackmagic chose to declare itself as a video capture device, and according to the operating system, a video capture device can pass both video and audio. But not just audio.
Looking at the video signals themselves, unless you are still using analog, the audio is actually interleaved into each video frame. That means to capture audio, you have to start with a video signal and extract the audio from it.

Now, it is technically possible for Blackmagic to write a driver that declares the device as a sound card instead of a video capture device (or a hybrid device, or some other kind of device) and shove the audio down the cable in a non-video signal format, however it would undoubtedly increase the cost of developing their drivers. So they choose not too.

Many would argue that users who want an audio only capture device would be much better served with an actual USB sound card. They have far less latency, support higher sample rates (Blackmagic is limited to 48khz since that is the TV industry standard), have better quality pre-amps, and come with a combination of balanced, unbalanced, digital and optical connections.