38499-70 701531471561_sub_f_1532161730.mp4 -

: A unique identification number, often the serial number of the recorder or a specific event ID.

The primary feature of this file is that it is a of a security recording. Because it is a "Sub-stream" file, it will have a smaller file size and lower image quality compared to the primary recording, making it easier to share or upload. 38499-70 701531471561_Sub_f_1532161730.mp4

The filename indicates it is likely a video file recorded by a DVR or NVR security system (often associated with brands like Hikvision or Dahua ). Meaning of the Filename Parts: : A unique identification number, often the serial

: Typically represents a system ID or a specific camera group code. : A unique identification number

: Often signifies the recording type, such as "File" or "Full" (continuous recording).