Live video connectivity



  • I'm in the middle of show previews and am having some inconsistency with our live video feed.  I sure could use some feedback and input.

    I'm running izzy on a macbook pro 10.8.5  2.7GHz i7 16GB  izzy version 1.30f24
    Black Magic Ultra Studio mini recorder is my video input card via thunderbolt.  We are using a JVC gz-ex355bu camera and its hdmi mini output to a video extender over cat 6\.   Izzy is outputting to front and rear projection via 1 thunderbolt to vga and 1 usb to vga.
    When we check live video feed before our house opens everything is fine.  We get a the preview window in live capture settings no problem.  However, by the time we get to act 2, when the live feed is finally used, we are not getting the live feed any more.  The box in live capture settings is black but doesn't receive video.  It should be noted, do to staging issues, the camera is unplugged from the setup until about 2 minutes before it is used.  We have had some success stopping capture, scan for devices, and then restarting live capture.  But not always.  Currently the video input is uncompressed.  I am wondering if I should compress the live feed to Photo-JPEG but am worried if we do this I will need to reset actor values in the scene to retune the projected image.  Also, restarting izzy seems to help get the live feed back up and running but this really isn't an option mid-show.  What am I missing that I can do to make sure our live input is consistent.  Thanks in advance and let me know if you need further information to help me diagnose.


  • I would for start use the latest release of Isadora 1.31f06.

    Secondly I would not touch the camera cables during the show. To me it is call for trouble. Maybe I would activate live capture few minutes before the live feed. Just to avoid possible problem biuld-up. Also I would check the Console for possible error messages at the time of lost connectivity.
    Make sure you have the latest BM Studio drivers(I do not know if there are any to run this device). 
    And maybe test the the extender before anything. These devises are capricious sometimes, specially cheaper ones.
    So in short run a test before the show until you get no live feed . Then troubleshoot from step to step starting with Cat6 extender.


  • I just spoke to an izzy guru friend of mine.  He suggests that because the camera is disconnected for so long that the BM Ultra Studio recorder goes into a standby or sleep mode.  I'm now inserting the 'capture control' actor into a handful of scene prior to the live feed scene in hopes to wake up the BM card.  I'll see if this works for our matinee today.  Any other suggestions?



  • Thank you, Vanakaru.  I didn't realize there was a newer build of Izzy - I'll update and will heed your additional advice!



  • we had problems experimenting with the blackmagic interface due to heat issues, after a while it get's really hot and they just switch off

    if you look inside that little box you see that they have no heatsink on the chip it is a really poor design 
    we solved it by installing a hugh heatsink on top of the case with some thermal paste
    additionally i would recommend to use a hdmi -> sdi converter instead of the cat6 extenders much more reliable


  • @bartersound

    I'm not sure why the video feed is stopping. Perhaps it could be the heat issue mentioned by @m_theater, but perhaps it is Isadora. I have not tested a long-term capture with a Blackmagic device myself.
    I wonder if other users have had problems capturing for a long time from HDMI/Thunderbolt input.
    Has anyone else had similar experiences?
    Best Wishes,
    Mark


  • you could use the black syphon app

    this would show you if you have a problem with the interface or just with the way isadora handles the blackmagic / interact with your drivers
    i heard a lot of people [complaining](http://forum.blackmagicdesign.com/viewforum.php?f=11&sid=e35116300d4bafc0ebf39d94c95fa8ba) about the 10.x decklink drivers perhaps you have to go back to 9.x
    anyway because of the native sdk access through blacksyphon you should gain a better timing / less delay
    and if you have a thermal problem the connection will be lost regardless what app you use
    hope this helps
    best clemens


  • Hi everyone.  It's been a while since I followed up on this tread...time flies when you are busy.  Here is an update on where this problem lead us.

    The show is now closed and we came up with a couple technices to allow us to get video signal thru the mini recorder with little to no problems.  After speaking with a guru friend of mine he suggested that because we were not using the mini recorder in act 1 it likely had gone into a hibernation mode and needed to be woken up.  Again, because of the back stage circumstances we test the video at preshow and then the camera is disconnected not used until act 2\.  My friend suggested putting an 'input control' actor in the a scene before we needed the live feed.  We also did a second video check at intermission.  Together it seemed to help keep the video input online until we needed to use it.  There were only 2 or 3 instances during our 60 show run when the feed did not come in.  At this point our video op simply toggled the 'start live capture' once or twice and live video began to flow.
    Thanks for the information about Black Syphon.  We will be using live video again this fall so I will be experimenting more with it.  My overall experience with the BM mini recorder was great when said and done.  Affordable and great quality with minimal delay (about 150ms) from input to projector output.

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