Pm020.mp4

: Use the VLC Media Player to open it, as it supports almost all MP4 variants and codecs.

If you have the file and are unsure what is in it, you can safely inspect it using these methods: PM020.mp4

: Right-click the file and select Properties > Details (Windows) or Get Info (macOS) to see the date it was created, which may provide a clue to its origin. : Use the VLC Media Player to open

Many digital video recorders (DVRs) and CCTV systems use "PM" (often short for "Picture" or "Post-Meridiem") followed by a sequence number. would typically be the 20th clip in a recorded sequence. 2. Project or Media Management would typically be the 20th clip in a recorded sequence

: It almost certainly contains AAC (Advanced Audio Coding) audio.

Since the file has an .mp4 extension, it uses the container format. This means: