PLANET NVR-420 - Manual (Page 41)

You can alternatively choose to export the recorded video to JPEG images
by choosing the "Export as JPEG images" option.
Specify the Start time/End time (or export length) and click "Start" to begin
exporting. You will be notified once the process is completed successfully
41
4-CH H.264 Network Video Recorder with HDMI
User’s Manual of NVR-420