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SDI Timecode output from Ursa Mini 4K? Arduino controller

PostPosted: Tue Jul 18, 2017 6:40 pm
by felixgeen
Hi guys,

I am here to ask a question about the timecode output from Ursa Mini 4K. In previous versions of the Ursa there was a dedicated time-code SDI port but now that is gone, is there any easy way of extracting the timecode information from the SDI signal? I presume that the SDI signal is going to be full of lots of complex coded raw data and very hard to extract a time-code from without the proper hardware.

My objective is to use the timecode from the camera to very precisely fire one LED light per frame of video. I am shooting in 120 FPS and need only one LED on per-frame. I am using an Arduino to control my LED lights but unless I can read the signal from the camera I am unable to synchronise the lights to the camera shutter accurately.

Does anyone think that the Blackmagic SDI Shield for Arduino could help me? I have read people saying that this shield is only for controlling and sending signals to the camera and not for reading anything from the camera. Is this correct?

Any help would be much appreciated.
Kind regards,

Re: SDI Timecode output from Ursa Mini 4K? Arduino controlle

PostPosted: Sat Jul 22, 2017 8:20 pm
by felixgeen
Looking at page 119 of the manual ( ... Manual.pdf) it looks like the HD monitoring out will work with this piece of hardware to decode the SDI signal and provide sync pulses:

Is the frame rate of the HD Monitoring Output kept the same as the 4K recording frame rate? And when recording at 120fps 1080p cropped sensor, what frame rate will be sent through the HD Monitoring Output?

Re: SDI Timecode output from Ursa Mini 4K? Arduino controlle

PostPosted: Sun Jul 23, 2017 4:58 pm
by Howard Roll
LTC is not a sync, it's just metadata that gets recorded into the stream. If you want to sync the camera to your LED assembly use a sync generator that provides black burst or tri-level. Then you can sync the Arduino controller to the sync generator and be good to go. Trying to sync to the camera's output would be a waste of time because there is processing delay between capture and output, not to mention the camera will drift anyway if it's not sync'd to an external source. Probably a lot more info in the machine vision world than here. Good Luck.

Re: SDI Timecode output from Ursa Mini 4K? Arduino controlle

PostPosted: Fri Dec 08, 2017 1:39 am
by felixgeen
Thank you Howard!
Sorry for my slow reply.

Could you give me some more information and recommendations on what sync-generator i should look into?

Thanks again