This specific naming pattern is characteristic of Samsung Galaxy or other Android smartphones . Unlike iPhones (which typically use "IMG_xxxx"), these devices generate filenames based on the exact second the recording started.
A common video container format developed by Apple, similar to MP4. Vid 20181003 131635-8m4v
The "8" and the dash before it suggest this might be a temporary file, a recovery fragment, or a file renamed by a cloud sync service (like Google Photos or Dropbox) to resolve a naming conflict or indicate a specific encoding version. Common Use Cases Files with this specific timestamp often appear in: This specific naming pattern is characteristic of Samsung
Try changing the .8m4v suffix to a standard .mp4 or .m4v . a recovery fragment