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Thread: NDI SDK and PTZ control

  1. #1
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    NDI SDK and PTZ control

    It's been noted that the PTZ controls in Studio Monitor are vastly better than what's possible using third party apps like vMix.

    When I approached the vMix user community to inquire about this, I found that they are currently limited by the inability to ascertain the camera position via the SDK. So, I'd like to ask that the SDK be extended to support this functionality.

    Third party apps should be able to have smooth, fluid control of a PTZ camera...not just quick reposition, which is all that's currently possible.

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    NewTek Engineering ACross's Avatar
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    Quote Originally Posted by mjgraves View Post
    It's been noted that the PTZ controls in Studio Monitor are vastly better than what's possible using third party apps like vMix.
    When I approached the vMix user community to inquire about this, I found that they are currently limited by the inability to ascertain the camera position via the SDK. So, I'd like to ask that the SDK be extended to support this functionality.
    Third party apps should be able to have smooth, fluid control of a PTZ camera...not just quick reposition, which is all that's currently possible.
    Being the person who actually wrote the Studio Monitor code, I can 100% assure you that there is nothing we are doing that is special at all. It literally makes direct calls to the NDI SDK and does not in any way do anything that the SDK does not support - it actually uses it. The only thing I did is spend quite a bit of time messing with the "feel" of the controls in terms of their sensitivity (their response to mouse movement is actually non linear, etc...)

    To the extent that any vendor (even competitors) wants help in knowing what set of commands we use, I would be very happy to share.

    Andrew

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    Dr Cross,

    Thanks for the reply. That's very interesting. I'll certainly relay this to Martin Sinclair at vMix. It may point to some more fundamental differences in how they implement PTZ remote control.

    Thanks again,
    Michael Graves

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    Quote Originally Posted by mjgraves View Post
    It's been noted that the PTZ controls in Studio Monitor are vastly better than what's possible using third party apps like vMix.

    When I approached the vMix user community to inquire about this, I found that they are currently limited by the inability to ascertain the camera position via the SDK. So, I'd like to ask that the SDK be extended to support this functionality.

    Third party apps should be able to have smooth, fluid control of a PTZ camera...not just quick reposition, which is all that's currently possible.
    Development of PTZ Support in Sienna NDI Monitor went through the same sort of challenge - initially it used absolute PTZ positioning - which only makes sense when you know the start position.
    Sienna NDI Monitor then added relative camera positioning mode, which is also what NewTek's NDI Monitor uses. This can provide a more predictable behaviour. Both control modes remain in the product to serve different needs.

    http://www.sienna-tv.com/ndi/ndimonitor.html

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    NewTek Engineering ACross's Avatar
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    Quote Originally Posted by livepad View Post
    Development of PTZ Support in Sienna NDI Monitor went through the same sort of challenge - initially it used absolute PTZ positioning - which only makes sense when you know the start position.
    Sienna NDI Monitor then added relative camera positioning mode, which is also what NewTek's NDI Monitor uses. This can provide a more predictable behaviour. Both control modes remain in the product to serve different needs.
    http://www.sienna-tv.com/ndi/ndimonitor.html
    FWIW ... I have spent 10+ years working with different PTZ cameras for our products and all of our implementations started out relying on absolute PTZ positions (and the ability to query them back from the camera). After spending years battling with getting this to work right and looking how the really good implementations of hardware PTZ controllers worked we realized that the assumption that we had been making was just wrong and that realistically most cameras have very poor performance and accuracy on positional queries and because you do not know when they might still be in motion that even working out whether your "current position" was even currently valid was a problem that ended up causing one hack on-top of another. We got it working well for some cameras but there where at least an equal number that did not feel right at all. When we moved to controlling the speed instead of the position (which is what real world PTZ controllers do) the end result was much better ... and what Studio Monitor does. This is also why we implemented the NDI SDK commands as we did. We can look at extending those commands however in my experience it does not result in better control.

    A.

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