Technical guide
Video Metadata Explained: MP4, MOV, and QuickTime Atoms
Last reviewed: September 16, 2026
Understanding video containers and streams
A digital video file is not a single monolithic entity. Instead, it is a structured container package that bundles together one or more compressed video streams (such as H.264, H.265/HEVC, or AV1), compressed audio streams (such as AAC, MP3, or Opus), subtitle tracks, and descriptive container metadata.
The most common video container formats in consumer use are MP4 (MPEG-4 Part 14) and Apple QuickTime File Format (MOV). Both formats adhere to the standardized ISO Base Media File Format (ISO/IEC 14496-12) architecture.
The box and atom hierarchy
ISO-BMFF containers organize information into structured data units called boxes (historically termed atoms in QuickTime). Each box begins with an 8-byte header specifying its size and a 4-character identifier (FourCC code). Boxes can be nested recursively inside parent containers.
Common top-level atoms include:
- • ftyp (File Type Box): Declares file container brand compatibility and version specifications.
- • moov (Movie Box): The container holding all metadata for the presentation, including duration, timescale, and track definitions.
- • mdat (Media Data Box): Contains the raw, encoded audio and video sample payloads.
- • trak (Track Box): Sub-container within moov defining individual video, audio, or subtitle tracks.
- • udta (User Data Box): Contains user and hardware metadata, including copyright tags, camera settings, and GPS strings.
- • meta (Metadata Box): Houses structured key-value item lists (keys and ilst atoms) used by Apple and modern cameras to store location coordinates.
How location and camera data are stored in video
Apple iOS devices and modern digital cameras record location data in two primary ways: through the user data atom (udta) with a legacy coordinate string, and through the metadata item list (meta.keys and meta.ilst) using reverse-DNS keys such as com.apple.quicktime.location.ISO6709.
These strings store geographic coordinates according to ISO 6709 standards (for example, +37.7749-122.4194+015.000/). Anyone with a basic container inspector can read these coordinates and plot your recording location on a map.
Fast, lossless metadata removal
Because the media payload (mdat) is physically separate from the metadata boxes (moov/udta/meta), it is possible to clean video metadata without decompressing or re-encoding the audio/video streams. CleanMyPhoto neutralizes metadata atoms by converting them into inert blank boxes, delivering instant privacy with zero quality degradation.