MP4 and MOV internals: the moov atom, keyframes, codecs and repair methods.
October 9, 2026 · 7 min read · How it works
Should your phone, GoPro or drone record HEVC (H.265) or H.264? What changes in file size, playback compatibility, editing, and recovering a broken file.
October 8, 2026 · 6 min read · How it works
What fast start (moov before mdat) means for streaming, why cameras put the index at the end, and why that placement makes interrupted recordings unplayable.
October 7, 2026 · 6 min read · How it works
How the three kinds of video repair tools work, what they cost in time, money and privacy, and how to choose one without getting burned.
October 6, 2026 · 6 min read · How it works
What I-, P- and B-frames are, how a GOP works, why corrupted spots smear until the next keyframe, and what that means for repaired recordings.
October 6, 2026 · 6 min read · How it works
MP4 and MOV share the same box structure. What differs (brands, codecs, metadata, compatibility), when renaming works, and why both break the same way.
October 2, 2026 · 6 min read · How it works
Quick ways to test whether a video is healthy, truncated or missing its index: VLC, MediaInfo, ffprobe and a full ffmpeg decode test, with what each result means.
October 2, 2026 · 6 min read · How it works
A reference file supplies the codec settings a broken video lost. Here is how to pick or record one for iPhone, Android, GoPro, DJI and OBS.
October 1, 2026 · 5 min read · How it works
What fragmented MP4 (fMP4) is, how moof and mdat fragments work, why it survives crashes, where it is used (OBS, HLS, DASH), and its trade-offs.
October 1, 2026 · 5 min read · How it works
Why uploading private footage to online repair sites is a risk, how in-browser processing keeps files on your device, and how to verify that nothing is uploaded.
October 1, 2026 · 6 min read · How it works
A plain-English tour of the MP4 file format: ftyp, mdat and moov, and why a missing moov atom makes a perfectly good recording unplayable.