The hyphen suggests the first number might be a User ID or Channel ID , while the second number represents a specific Session or Video ID . How to Identify or Open the File
If you have this file and are trying to determine its content or fix a playback issue: 582563926479-5516659793871.mp4
If the video won't play, ensure the .mp4 extension hasn't been added to a different format, such as a .264 raw stream from a security system . The hyphen suggests the first number might be