# Checking the Validity of Exported Videos

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Watermark allows users to check for validity of footage to determine whether or not any modifications were ever performed to the native footage. Any videos exported by Nx Witness (either single camera or Multi-Videos) can be checked for validity.

To check the validity of exported videos:

1.Bring the desired video onto the layout

2.Open the context menu and select Check File Watermark (shortcut Alt+C)

3.If the file is in its original state, the check will succeed:

4.If any modifications took place, the check will fail: