: This suggests the file was originally an .mp4 but has been converted to or wrapped in an .mkv (Matroska) container.

: Usually a sequence number or a millisecond timestamp to prevent duplicate filenames.

This filename follows a standard naming convention used by many Android camera apps, indicating it was recorded on , at 10:36:57 AM . VID : Short for Video. 20221213 : The date in YYYYMMDD format (December 13, 2022). 103657 : The time in HHMMSS format (10:36:57 AM).