Recorded frames from USB Camera don't match number of timestamps in the block

Tech Note: TN0987
Product: Synapse
Version: All
Date Added: 2018-06-11


The number of frames in the avi video file is greater than the number of timestamps in the block of data.


The camera timer runs in software, specifically on the Cam1 tab that you see during a Synapse recording. This has two noticeable effect:

  1. At the beginning of the recording, the frame timer doesn't start until the interface is created, which can happen after the hardware trigger initiates recording. You can give the interface more time to create before the recording begins by setting the Persistence Load Delay option longer in the Menu → Preferences → Advanced tab. You should see a shorter delay between when the recording starts and when the camera triggers begin.

  2. At the end of the recording, the hardware stops receiving data, but the camera tab is still open for a short time and is still collecting frames, which creates extra frames at the end.

The frame timestamps that you have in your TDT recorded block will always match the frames recorded in the video, starting from the first frame and timestamp. If a frame was missed during the recording, there won't be a timestamp in the tank for it either. There may be some extra frames in the video but these will always occur at the end.