Atomos Ninja Recording Stopped — File Won't Open

The Atomos Ninja, Ninja V, Ninja V+, Ninja Phone (2024), the new Ninja TX / Ninja TX GO / Ninja RAW family (announced 2026), and the Shogun lineup — including the recent Shogun Ultra and the rack-mounted Shogun AV-19 (Feb 2026, ships March 2026) — are the gold standard for external ProRes recording — and the gold standard for one specific failure mode. When the unit loses power mid-recording (battery dies, AC bricks out, the cable wiggles loose), the recording stops abruptly and the file on the SSD ends up large, looking healthy, and absolutely refusing to open. This page is about that file.

We've recovered a lot of these. The patterns are consistent and the fix is well-understood. The good news: in nine out of ten of these cases, the actual ProRes frames on the SSD are intact. What's missing is the QuickTime container metadata that tells your editor where the frames live.

What's on the SSD when a Ninja stops mid-record

Atomos units record ProRes (or DNxHR / DNxHD on some configurations) to MOV containers. The container is finalised at the moment you press stop. If power is interrupted before that moment, the file looks like:

[ftyp]               ← container declaration, intact
[mdat starts here]   ← all your ProRes frames + LPCM audio interleaved
... a few hundred MB to several GB of frames ...
[mdat ends abruptly]  ← no MOOV, no closing atoms

Many MOV-aware tools assume [ftyp] plus a missing or unparseable [moov] means the entire file is garbage. It's not. The frame data sitting in mdat is the take.

Why this hits Atomos units specifically

Atomos units are popular precisely because they bypass the camera's container limits — you get longer takes, higher bit-rates, and ProRes / DNx codecs the camera itself can't write internally. The trade-off is that they're also a separate device with separate power. If the camera body is fine but the Ninja's battery dies, the recording on the SSD never gets a clean stop.

Common triggers we see:

• NP-F battery exhaustion during long-form interviews / documentary work.
• D-tap cable working loose when the camera operator moves.
• AC adapter brownout in venues with iffy power.
• SSD ejected while the unit is still writing (rare, but happens with hot-swap mistakes).
• Firmware crash on older Ninja V+ firmwares — the unit reboots, the recording is lost in the same way as a power cut.

Two Atomos-specific quirks our engine handles

Most generic recovery tools will return a file that almost works. The audio is usually where they fall down. There are two specific reasons.

1. Little-endian PCM where everything else is big-endian

Atomos units write PCM audio as little-endian 24-bit. QuickTime's MOV format is historically big-endian. Many recovery tools do an unconditional byte-swap when rebuilding the audio track — which works for camera-internal audio but produces audio that sounds like static for Atomos files. We detect endianness from the actual sample distribution and don't swap unless the data tells us to.

2. Audio chunk placement within the video group

In MOV interleaving, audio chunks sit alongside video chunks in mdat. The exact position — before the video chunk in the same group, or after — affects timeline sync. Atomos files want audio chunks at the start of the video group; placing them at the end creates roughly half a second of audio drift that no amount of stretch correction fixes. We learned this on a specific Ninja V firmware revision and it turned out to apply across the line.

If you're using a generic MP4 repair tool and it returns a file with audio offset by ~0.5 s, that's almost certainly what happened.

What you can try yourself

1. Connect the SSD to your computer and copy the file off the disk before doing anything else. Never attempt recovery on the source SSD — work on a copy.
2. Atomos's own AtomOS rescue mode. Newer firmware has an "incomplete recording recovery" option that runs on the unit. Try this first — if it works, you're done in two minutes. If it doesn't, your file is in our territory.
3. untrunc (open-source). Excellent for Atomos files specifically because the failure mode (truncated, missing MOOV, otherwise intact) is exactly what untrunc was built for. You need a "good" reference file from the same Ninja unit at the same recording settings.
4. ffmpeg -i broken.mov -c copy out.mov. Won't recover but will tell you what FFmpeg sees.

If you don't have a matched reference file, untrunc can't help. That's the most common reason to use a service like ours.

How our recovery handles a Ninja file

• No reference clip required. We extract codec parameters from the first complete ProRes frame in mdat. ProRes frames carry their own width, height, and codec four-cc (apcn, apch, apcs, ap4h, etc.). That's enough to rebuild a valid stsd.
• All ProRes flavours. Proxy, LT, 422, HQ, 4444, 4444 XQ. The codec four-cc identifies the variant; the rest of the pipeline doesn't care.
• DNxHR / DNxHD also supported (Ninja and Shogun can record either).
• Audio handled correctly out of the gate (the two quirks above).
• co64 for files over 4 GB, which is most professional Ninja takes.

What you do

1. Upload the broken file. Up to 50 GB. Drag and drop.
2. ~1 minute later you get a free 5-second preview. Picture and audio. You can scrub.
3. If it looks right, pay and download the full recovered file. If it doesn't, adjust parameters interactively or escalate to a human review at no cost.

FAQ

Does this work on Ninja, Ninja V, Ninja V Plus, Ninja Phone, Ninja TX, Ninja TX GO, Ninja RAW, Shogun, Shogun Connect, Shogun Ultra, Shogun AV-19, and Sumo? Yes. The container format is the same across the line. The codec (ProRes / DNx) and audio configuration vary, but our engine identifies them from the data.

ProRes RAW recordings — supported? Partially. ProRes RAW frames are detected, but the metadata required to reconstruct the full ProRes RAW stream (camera-specific colour info, sensor metadata) is sometimes missing in the worst-corruption cases. We try and tell you fast if we can't.

My Atomos was recording from a RED / ARRI / Sony Venice — does that change anything? No. The Atomos writes ProRes / DNx regardless of source camera. The recovery is identical.

Can I recover only the audio, not the video? Yes — escalate the case after upload and ask. We can extract audio-only.

My file plays for 30 seconds and then crashes Premiere/Resolve. Different failure mode (mid-file corruption, not missing MOOV). Still recoverable in most cases. Upload it and the diagnostic will tell us which pattern it is.

Related

• What "MOOV atom not found" actually means
• Atomos Shogun ProRes corruption
• How our recovery engine works

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