ClipMend vs untrunc
untrunc is the open-source tool that pioneered rebuilding broken MP4/MOV files from their raw frames. It's genuinely good — and free. The catch on a Mac: it's command-line only, with no official Mac binary. ClipMend does the same index reconstruction as a native macOS app with one button.
Respect where it's due
untrunc (the maintained anthwlock fork, ~3.2k★, GPL-2.0) proved that a truncated or index-less MP4 can be rebuilt by reading a healthy reference and re-mapping the frames. If you're comfortable on the command line and don't mind compiling, it's a solid free option. ClipMend isn't a fork of it — it's a separate clean-room engine — but it solves the same core problem.
Side by side
| untrunc | ClipMend | |
|---|---|---|
| Price | Free (GPL-2.0) | Free public beta · no subscription, no per-file fee |
| Mac install | Compile from source (ffmpeg + build tools); no Homebrew formula, no official Mac binary | Download the app and run · Apple Silicon native |
| Interface | Command line (the GUI ships only in the Windows builds) | Native macOS UI · drag, Analyze, Rescue |
| Reference clip | Always required (broken + healthy example) | Often needed too — but self-rescue works with no reference on cameras that embed parameters (e.g. GoPro) |
| Free diagnosis first | — | Shows what's recoverable before you commit |
| Audio & B-frame order | Varies; multi-track audio issues are reported by users | Recovers AAC/PCM audio and restores B-frame display order bit-exactly |
| Batch | Scriptable (you write the loop) | Built-in batch rescue for many segments at once |
| Local / private | Yes | Yes — nothing uploaded |
Competitor details verified June 2026 from the project's GitHub and README. Open-source projects move fast — check the repo for the latest.
Where untrunc may still be the better pick
- You're on Windows or Linux — ClipMend is macOS-only.
- You want fully free and open-source, and the command line doesn't bother you.
- You need to script repairs into a larger pipeline.
Where ClipMend pulls ahead
- One button, no compiling — drop the file, Analyze, Rescue.
- Self-rescue without a reference for GoPro-class cameras, reading exact fps from the stream.
- Honest diagnosis tells you up front whether the frames are recoverable.
- Frames copied 1:1 — no re-encode, no quality loss — and it runs entirely on your Mac.
FAQ
Can ClipMend open a file untrunc couldn't?
Sometimes — different engines handle edge cases differently (fragmented MP4 from OBS, wiped headers, self-rescue without a reference). The free Analyze step tells you whether ClipMend sees recoverable frames.
Is my video uploaded anywhere?
No. Like untrunc, ClipMend runs entirely on your machine. Nothing leaves your Mac.
Try the one-click Mac alternative
ClipMend for macOS — free public beta. The analysis is free and shows what's recoverable first.
⬇ Download ClipMend