Ndi genlock aximmetry

Eifert@Aximmetry

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Hi,

Could you specify what you want to synchronize with the NDI 5 source?
Note that, for example, a receiving device or software cannot command NDI sources to enable genlock and synchronize with each other.

Warmest regards,

rubendesnoo

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When we use trackman, stype etc we can sync our engine with genlock right? To make sure we dont get framedrops.

I use a ptz camera without a reference input...But, I can use a NDI sync source in my camera to get the FreeD and Videosignal from this PTZ synced with each other. This is just a ndi 5 stream, and this sends also a timecode signal in the protocol.

The last step in this system should be syncingb the unreal scene(aximmetry engine) with the same NDI sync source right? I know for example this works like that in other software and I would love to test this in aximmetry. Unfortunately I cannot find the NDI source as a option for syncing in the aximmetry settings.

Best regards

Eifert@Aximmetry

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Hi,

The PTZ's FreeD tracking and video are likely already synchronized, operating on the same clock, whether or not the system supports NDI genlock.
When using non-PTZ cameras, where the tracking device and the camera are two separate units, genlock provides the advantage of synchronizing these devices according to genlock's clock. However, in the case of PTZ cameras, there is no such advantage since it is a single device generating both the tracking and video signals.

Also, note that while the Tracking Delay should remain consistent over time, genlock doesn't ensure there will be no delay between the FreeD and video signals. More on the topic here: https://aximmetry.com/learn/tutorials/for-studio-operators/syncing-and-genlock/

Unfortunately, the Free-D protocol does not allow embedding a timecode, so you cannot use Timecode Sync with it. (Also, currently, Aximmetry cannot extract timecode from an NDI stream.) These mean that you have to adjust the Tracking Delay manually in this case (or use Detect Delay).

Currently, Aximmetry cannot be synced to an NDI genlock. If you are interested, I can add this feature to our request list. Note that implementing this feature would synchronize Aximmetry's output to match the NDI output of the PTZ camera, ensuring that all frames end up being utilized in Aximmetry from the PTZ camera.

Warmest regards,

JohanF

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@ rubendesnoo: I think you’ve misunderstood how genlock works in a system like this. Genlock won’t prevent frame drops (that’s a performance issue) and you don’t genlock the engine itself. You genlock the camera and tracking system to the same clock source and optionally the output of your capture card. If your FreeD data is generated in your PTZ camera, it would (hopefully) already be genlocked, without any need for external sync. Genlocking your capture card won’t make any difference to tracking sync or frame drops, since the capture card output is buffered on the card. When you genlock the output, you simply remove the need for any frame re-synchronization in your downstream vision mixer, which will earn you a frame or two less delay in the mixer, since it won’t have to buffer and re-clock the signal. Visually you won’t see a difference.
I don’t think using NDI as a sync source is a good idea. Any dropped frames due to network lag would cause the whole rendering to stutter. Sending the timing variable NDI signal into Aximmetry where it’s buffered and clocked to the internal system clock sounds like a better plan. I don’t know how Aximmetry currently handles NDI signals, but if buffersing is correctly implemented you wouldn’t see any dropped frames as long as your network can keep up.
Out of curiosity, what software currently uses the NDI Genlock? I haven’t come across it and I can find very little information on it.

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