: If you didn't download this file yourself, be cautious. Randomly named .mp4 files can sometimes be used to disguise malware. Before opening it, run it through a scanner like VirusTotal to ensure it is a legitimate media file and not an executable script.

: The suffix _source often indicates that this is the original high-resolution version of a file before it was compressed for streaming. The random string ddgrinch5vg4a is likely a unique ID assigned by a server (common with sites like Discord or Twitter/X).

Do you have about where you found this file or a description of what happens in the video?

mp4box with growing .mp4 source · Issue #1692 · gpac/gpac - GitHub