Capture video from one mac on another mac via blackmagic intensity



  • Hi everybody,
    I have just bought a Blackmagic Intensity Extreme video card, because it says on their website that :

    "Blackmagic Desktop Video products with HDMI inputs can capture from the DVI or HDMI outputs of a graphics card, providing the source is not HDCP protected.To capture from a graphics card, the output must be set to a supported resolution of the Blackmagic Desktop Video product you are capturing to. For example if you want to capture 720p50, the graphics card’s output would need to be set to 1280x720 @ 50Hz."

    So I have tried to send 1920x1080/24f video from Mac 1 to the Blackmagic Intensity, and from their to go into Isadora on Mac 2 and capture the video.
    However, in the input settings in Isadora the Blackmagic card is recognized, but the preview just shows a black window.

    Any help would be greatly appreciated!



  • I have been doing this between a Windows 7 machine into a Macbook Pro.

    The settings have to be exactly right.
    I have had best luck using the 1920p 30 settings. . . but you have to make sure the setting are correct on the sending computer as well. (check the refresh rate in the advanced settings on a Windows machine to make sure you are sending the number of htz for your desired frame rate. . . . Right now I am actually sending a 24htz progressive signal from my displaying computer to get a 24fps signal that the BM can see. . .)
    Run the Media Express software that came with the Blackmagic and you will be able to monitor in the input. Once you get the settings right on both your sending and receiving side the signal will just pop up in the log and capture screen without much fanfair.


  • Thanks Alex.
     Can't get it to work with the exact same settings on my old (2009) MacBook Pro, and my new Retina (2013). Guess Neither Media Express nor Isadora recognize the signal sent from the 2009 MAcBook Pro - however, the video beamer does with no problems...
    seems to have to do with the refresh rate, which I can't set (in the system preferences they don't appear under displays/scaled, as usual) for the BM.
    Will have to keep on testing, tomorrow with a friend's Windows machine.



  • What resolution are you using? I had problems with a similar age macbook pro. The inputs of the blackmagic gear are very picky. Many TV's and projectors are much more lax with standards. I had no problems running my 2009 mbp in 1920x1080 50i but other resolutions were not supported by the graphics card properly. The selection for this resolution was also not clear on the laptop, (if I remember there were 2 listings for the same resolution but only one was interlaced. Depending on the video card switch res-x may help you to get the exact resolution and refresh rate, there is a free trial of this. Also the input of the blackmagic gear supports only YUV not RGB over HDMI.

    If you try plugging the retinas output into the capture box (it has enough ports) you should get all the proper resolutions listed in details and functioning - remember you also have to set the input and standard on the blackmagic settings in the systems preferences. Some versions of the blackmagic drivers and firmware also have different capabilities. There is a user forum for blackmagic on their site, you will find a lot mroe information there. If it is not a setting or limitation of your graphics card you may find it could be solved by a driver upgrade/downgrade to a specific version
    Fred


  • @aolis: Today I have tried your setup (Windows 7 machine sending to a MBP Retina). It didn't work, because the Windows machine would not even recognize the BM as an external device/monitor, so we couldn't set anything in the advanced settings. How did you get your BM to recognize the Windows machine?

    @Fred: Thanks a lot for all the advice! I will take my time to work through the suggestions. Today I have tried the Switch-Res X demo (great tool!), and it did in fact recognize the BM as a second monitor. But even with the identical settings and refresh rates all I got in Media Express and Isadora, was a black window...



  • Hmmmm. Not sure what I did specifically but windows machine did see the BM device as a BM device and provided the proper settings on it. Might have something to do with the graphics cards but bit sure. Will be working on this again tomorrow and will see what the windows machine says.



  • Great, thanks!



  • what resolution are your trying with?


  • Tech Staff

    @stj

    The 2 resolutions that always worked for me with BM devices are either 720@50p / 720@60p or 1080@50i / 1080@60i.

    Best
    Michel



  • @Fred @Michel
    I have tried almost every resolution, including 720@50p and 1080@50i, but could neither capture from the Windows 7 machine, nor the MBP 2009 to my retina MBP 2013.
    However, capturing from my Panasonic camcorder at 1080@50i works like a breeze...

    I guess for my upcoming show  (end of March) I will go for the AirServer solution to mirror one screen on another machine. Have worked on this yesterday as well, and works perfectly, no noticeable lag (thanks @Rainbow).

    Thank you everyone for your help!



  • In our windows machine we are using a Quadro5000 graphics card. Sending at 1920x1080 at 24 htz. In the Black Magic I am capturing HD 1080: Blackmagic HD 1080p 24 - 10 Bit. .. Works great. . .


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