Full HD live input with no lag
  • ricovilarouca
    junior Member
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    Joined: Sun Jun 12, 2011 7:25 am
    Location: Rio de Janeiro - Brazil

    Full HD live input with no lag

    by ricovilarouca » Fri Jan 31, 2014 6:35 am

    Hi guys,

    I´m planning a dance performance that uses a top camera like a live input to madmapper and been mapped and projected in screen at the same time. I´ll use a good mac pro (not the new trashcan, too expensive for that :)) and I have 2 main doubts, maybe someone can help:
    - I need a good image, since this top capture will be zoomed and the scene itself is full of colors and lots of movement. I just can have minimal (or none I hope) lag cause it´s a coreography. My first camera choice was an Canon EX1 or EX3 but it looks like a very expensive option. Had anyone use a good HD camera with an HD SDI output cheaper (but trustable) than that?
    - I was looking for a good capture device to bypass the signal to madmapper. This external ultrastudio - not the 4K, the express model - looks very good (http://www.blackmagicdesign.com/product ... olt/design), but some people believe that an internal PCI device probably will have less lag than an external device. Anyone has experience about that?

    Thanks in advance!

    Rico Vilarouca
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    Re: Full HD live input with no lag

    by NateMac » Fri Jan 31, 2014 5:46 pm

    Your biggest lag will be transcoding and MM Processing.
    Ideally you would want an uncompressed video signal from the camera into whatever your working in, but I'm not sure if MadMapper can handle an uncompressed video signal.
    If your working with a cheese-grater MacPro you would have to install a Thurderbolt card to use the hardware your looking at. I would use one of BlackMagic's DeckLink Studio cards. This can take the uncompressed signal directly into your system, but again, I'm not sure if MM will expect it, it's a lot of Bit's.

    Do you mean Sony EX1/EX3, instead of Canon????

    A high Gain or ISO can also cause lag, you'll want to shoot at a higher frame rate, preferably 60fps(but small might call less lag but more stutter, it's give and take).

    Your never gonna get 1:1 going from a Camera ->HD-SDI -> PCI Card -> (Transcoder) -> MadMapper -> HDMI -> Projector
    Just to many steps, even MadMapper needs to do some processing, it's not a pass-threw application as much as we might think.
    Best thing to do, Rent and Test.
    Hope that helps.
  • ricovilarouca
    junior Member
    Posts: 4
    Joined: Sun Jun 12, 2011 7:25 am
    Location: Rio de Janeiro - Brazil

    Re: Full HD live input with no lag

    by ricovilarouca » Fri Jan 31, 2014 11:04 pm

    Thanks for your considerations NateMac.

    Yes, I´ll have the chance to test it, but I´m looking for some entry level to put the test on.
    Something that I already know is: On the blackmagic extreme PCI the SDI input is recognized by MM. My partner already tried and it works.
    I wonder that the new thunderbolt decklinks must have a good latency since they are aiming on the new Macpro (the black trashcan) where you cannot install a PCI board.
    About the uncompressed signal nature is something you cannot escape since it´s an SDI input, can you?
    The macpro will be a bold one, already equipped with a thunderbolt.

    I couldn´t understand the problem with EX1/EX3 instead of a Canon, could explain me better?

    1:1 are relative to latency?

    And again, thanks for your attention. Helped a lot.

    If anyone have other considerations I´ll be thankfull, since I believe this post could be a a good reference in a near future now that everyone here have more and more access to better cameras, more resolutions, better capture cards and larger bandwidths of information.

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