API to control capture on Intensity Pro 4K or DecLink

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Andrew Charlton

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API to control capture on Intensity Pro 4K or DecLink

PostWed Apr 27, 2016 1:53 pm

First, please note that I do not yet have any Blackmagic products -- I am investigating them with the view to possibly using them in a product (this means that at the moment any understanding I can have of the DeckLink API SDK can be purely theoretical; I cannot at present experiment to see what things do). Second, I am entirely new to the field of video capture, so I am not entirely sure what the questions are that I should be asking and I may not quite have the correct terminology.

The scenario is as follows: I am working on a training device that will present an instructor with 6 - 8 displays of what students are doing / seeing on the training device. (All these displays are generated via a Windows 10 PC at the instructor station.) One of the screens will be an Ultra HD display. During a training exercise we need to record the screens plus an audio channel so that the instructor can play back (including rewind / fast forward / jump to markers etc) after the training exercise to review it with the students.

To implement this record and playback functionality we are thinking of using a number of Intensity Pro 4K or DeckLink cards. We are intending to use an API to control recording and playback via the cards. Looking at the SDK documentation I saw that there are "IDeckLinkDeckControl::StartCapture" and "IDeckLinkDeckControl::CrashRecordStart" methods (section 2.5.26.28 and 2.5.26.31). However I notice that at the start of 2.5.26 that the IDecLinkDeckControl is for controlling interfaces via RS422 (which is not applicable for the cards I am considering). Can I use these methods to set these cards recording and if not what methods should I be using?

It could be that I am completely up the wrong tree, if so please can someone point me in the right direction for what I am trying to achieve.

Many thanks,
Andrew Ch.
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Matt Jefferson

Blackmagic Design

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Re: API to control capture on Intensity Pro 4K or DecLink

PostThu Apr 28, 2016 6:35 am

HI Andrew -
I know it can be daunting to come into the forum and ask questions here. Thanks for being interested in our products. First, the RS 422 is for the tape deck control using the Sony 9 pin RS422 deck controlling a card. This was one of the key functions of a capture card in the day so our SDI 4K, Studio4K, and Extreme family of cards continue to have this capability on our PCIE cards. It is not a function supported on Intensity Pro 4K nor Multi channel cards to start capture from 6 to 8 remote computers.

For example with your scenario, we do have the Decklink Quad 2 at $995 MSRP which via one card can capture 8 simultaneous captures from 8 different sources. If for example, the computers or laptops output a compatible 1920x1080 signal via HDMI you could use 8 of our new Microconverter HDMI to SDI with full size HDMI to SDI converters which are less than $100 retail.

Recommend the capture introduction section of the SDK manual which outlines the SDK approach for capturing.
2.4.1 Capture section is on page 26 of the SDK manual. BMD SDK does not provide multi channel SDK sample but it would possible to use capture preview sample and code to extend to more input channels.

Finally, see the contact for developer support email is on page 15.
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Andrew Charlton

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Re: API to control capture on Intensity Pro 4K or DecLink

PostThu Apr 28, 2016 8:28 am

Hello Matt,

Thank you for the advice. I had looked at the Intensity Pro 4K because it was advertised as "Incredible PCIe capture and playback...", which I understood to mean that it could capture and playback video -- so I am bit confused now. (I had envisioned using 6-8 of these in a single industrial PC).

So, with the Decklink Quad 2, would it be possible to configure it such that:
- it could pass through 4 inputs direct to 4 outputs
- programmatically control the inputs for recording (but still pass them through to the outputs at the same time)
- for playback, override the output with the playback video.

I realise that we would need 2 such devices in the PC to accomplish 8 channel recording.

(BTW just to clarify, I am not talking about remote computers. I am talking about a single computer driving 6-8 displays, and capture / playback of those displays. I am not sure if that makes a difference. I had thought the that each video output of the PC would then feed into a capture and playback device, the output of the device would then go onto the display monitor. From your description, it sounds like that topology would not work?)

Thanks again,
Andrew.
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Andrew Charlton

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Re: API to control capture on Intensity Pro 4K or DecLink

PostThu Apr 28, 2016 9:30 am

Hello Matt,

Just to clarify my last reply. Here is the sort of topology I was anticipating:

Image

(Although I am open to better suggestions).

Regards,
Andrew.
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Matt Jefferson

Blackmagic Design

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Re: API to control capture on Intensity Pro 4K or DecLink

PostThu Apr 28, 2016 11:11 pm

HI Andrew
PM me please your details and we can discuss the architecture of a solution. I believe a solution could be possible but we should talk about video input / output cards versus display (graphics cards)

I suggested a multichannel card here instead 8 Intensity Pro 4K is because a PC that would have 48 Lanes (8 cards slots of PCIE x4 for the intensity Pro 4K and a GPU usually x16 ) is pretty expensive. It could exceed the processing capabilities of most motherboards.

Matt
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Richard Clayton

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Re: API to control capture on Intensity Pro 4K or DecLink

PostWed May 04, 2016 9:11 am

Hi

I work with Andrew so can help to contribute to this discussion.

We need to record a total of 6 PC monitors driven from 6 graphics outputs on a single Windows 10 PC.

5 of the monitors are 1920 x 1080 (HD) and the 6th is 3840 x 2160 (4K)

The recordings need to be synced together so that as the instructor reviews the training with the student he can fast forwarded and rewind the scenario (different aspects of which are shown on the different monitors) and all the data recorded for the different monitors stays synchronised with each other.

Thanks
Richard
Last edited by Richard Clayton on Thu May 05, 2016 4:20 pm, edited 1 time in total.
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Andrew Charlton

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Re: API to control capture on Intensity Pro 4K or DecLink

PostWed May 04, 2016 9:33 am

Hello Matt,

Thanks for the reply. I did try to PM you through this site, but the message is sitting in my Outbox with no obvious way to make it go any further! I will watch it for a while and if it still does not go I will try and send you another message.

Andrew.

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