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Topics - schoenitz

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Chronos User Discussion / timing of external trigger
« on: September 06, 2023, 08:16:42 AM »

I'm seeing an unexpected delay when triggering externally via the BNC connector. In a test I'm recording a LED that flashes at 150 Hz for 100 ms. When it stops, I supply a trigger signal. This timing is more or less exact, I checked this with an oscilloscope.

Here's the signal I'm sending (the time axis is in expected camera frames):

The camera is set to record 2000 frames at 8245 fps. However, it doesn't seem to trigger at the time of the trigger signal but ~44 ms (~360 frames) later. The trigger timing in the camera is set to default - all 2000 frames are pre-trigger, and there are no post-trigger frames.

Here's what the camera is actually recording:

Is this expected? What to do about it? What I actually want to do is record 500 frames, and there I can't really tolerate a 360 frame mismatch.


We have a Chronos 1.4 camera, connected to a SMB share. As of now, saving an entire video file (H.264) takes close to 10 minutes. Saving to a SD card is not faster, and adds the overhead of then transferring the file. Saving in other formats (TIFF, DNG) is much slower.

I'm imagining that if the video encoding would produce monochrome data, the file could be considerably smaller, and saving would be faster. Does this make sense? Is it possible to do? I think one could change the color matrix to effectively produce monochrome output, but as long as the video format carries RGB, the file size would not be affected.

The context is that we're watching an object and would like to make decisions based on a video recording while the object exists. The object exists for maybe up to 20 min, sometimes much less.  Right now we can act on the video information once every 10+ minutes (not even counting the time needed to evaluate the video).  It'd be great if this time could be cut in half , or shortened even more.

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