Vivotek ND9542P 32-Channel 4K UHD NVR (No HDD) - Manual (Page 106)

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106 - User's Manual
7. Watermark password: Configure a password in a length of 16 to 64 characters.
You can use it to verify the authenticity of exported videos using the included video
player.
Select File > Verify Watermark.
Enter the password to verify. If the
Not match value is 0, the video is the
original and has not been tampered
with.