When you record a video on a smartphone or security camera, the device often assigns a sequential name if no title is provided. "456-1" likely represents: The 456th file in a specific folder or session.
A free tool that reveals the technical metadata (codec, resolution, and creation date) without needing to play the file. 456-1.mp4
In tools like youtube-dl , format code 456 might refer to a specific combination of video quality (e.g., 240p) and audio encoding. When you record a video on a smartphone
For web developers and power users, "456" is sometimes a specific used by platforms like YouTube. 456-1.mp4