If this file was recovered from an SD card (common for camera footage) and plays the "wrong" video or cuts out:

: Data recovery tools like Photorec sometimes fail to piece together fragmented videos, causing "overlapping" files. Ajb06577 mp4

: Use the "Convert / Save" feature in VLC to re-encode the file to a standard H.264 MP4 format. This often "smooths out" minor data errors. If this file was recovered from an SD