Sony FX3 XAVC Corrupted — Recover the Recording

The Sony FX3 (and the smaller-sensor FX30, plus the new FX2 released May 2025 — slotting between FX30 and FX3 with a built-in EVF and improved audio) is a documentary and indie cinema workhorse. It's also a camera people push hard — long takes, cold mornings, hot afternoons, dual CFexpress cards under pressure. The single most common failure mode is the same one that affects every modern camera: the recording stops without finalising the container, and the file ends up unreadable.

This page is about recovering FX3 XAVC files specifically.

What's in an FX3 file when it breaks

The FX3 records to MP4 (XAVC S, XAVC S-I) or MOV-style XAVC HS containers. The codec is H.264 or H.265 depending on mode (S vs HS), and All-I or Long GOP depending on the menu. Whichever combination, the container's MOOV atom is finalised at the moment recording stops cleanly.

When the FX3 doesn't get there, the file looks like:

[ftyp]   ← XAVC declaration, intact
[mdat]   ← H.264 / H.265 frames + LPCM audio interleaved
[????]   ← MOOV / metadata that should be here is missing

The frames are there. The map is gone.

FX3-specific causes we see

• Long-form documentary recording that runs into thermal throttling and a hard cutoff.
• CFexpress Type A card pulled before stop. Type A cards are small and tempting to remove without ejecting — common cause.
• Battery exhaustion during interview / event work without a power adapter.
• Hot-swap dual-card mistake during a recording.
• S-Log3 / S-Cinetone files behaving the same as standard recordings (no codec difference; same failure mode).

What you can try first

1. Sony Catalyst Browse / Catalyst Prepare. Sony's free tool understands its own XAVC variants. If the file's only issue is metadata-related, Catalyst sometimes opens it directly.
2. untrunc (open-source). Excellent at this exact failure pattern. Needs a healthy reference file from the same FX3 in the same recording mode.
3. ffprobe to verify what FFmpeg sees. If FFmpeg returns useful stream info, the file is more recoverable than average.
4. Try Resolve / Premiere directly. Some XAVC-aware editors are more permissive than QuickTime. A 30-second test costs nothing.

If those don't work, automated container reconstruction is the next path.

How our recovery handles FX3 XAVC

• No reference clip required. Codec parameters from the first valid IDR frame in mdat.
• XAVC S, XAVC S-I, and XAVC HS all supported. Codec is detected from the actual frame data — H.264 vs H.265 distinction is automatic.
• All-I and Long GOP both handled. The frame detection registers individual frames regardless of GOP structure.
• LPCM audio recovered correctly. FX3 audio is 24-bit 48 kHz LPCM. Endianness, sample rate, and channel layout are all detected from the actual data.
• co64 for files over 4 GB. FX3 long takes routinely cross 4 GB; we use 64-bit chunk offsets by default to avoid the silent overflow that breaks tools using stco.
• S-Log3, S-Cinetone, HLG metadata preserved through the codec data.

What you do

1. Upload the FX3 file. Up to 50 GB.
2. ~1 minute later, free 5-second preview.
3. Pay only if it works. Adjust or escalate if not.

FAQ

Does this work on the FX3 and FX30? Yes. Both share the XAVC codec family and container behaviour.

My FX3 was set to record proxy + main. Should I upload both? Yes if both are broken; if only the main is broken and the proxy is fine, upload the proxy as well — it gives us a known-good reference for resolution and frame rate.

Does this work on FX2 (May 2025), FX6, FX9, BURANO, and VENICE 2 files? Yes — the entire Sony Cinema Line (FX2, FX3, FX30, FX6, FX9, BURANO, VENICE 2) uses the same XAVC container family with similar All-I / Long GOP options. Same recovery path. BURANO files in the new X-OCN 16:9 mode (added in the March 2025 firmware) are partially supported — X-OCN-specific metadata may need manual reconfirmation but structural recovery works. The Cine Elite Codec (16-bit) recordings from VENICE 2 / BURANO are handled at the container level the same way.

Will S-Log3 / Cine EI gamma come back correctly? The colour profile is part of the codec data. The rebuilt file inherits it. S-Log3 footage comes back as S-Log3.

My file plays the first chunk and then breaks. Different failure mode — likely mid-file corruption rather than missing MOOV. Often still recoverable, sometimes by salvaging only the intact section. The diagnostic on upload tells us.

My recording was interrupted on dual cards (relay or backup mode). Both cards have broken files. Upload both. The two cards usually have offset cuts — between them, often you can stitch most of the take.

Is my footage safe? Server in France, auto-deleted after 48 hours, never used to train anything or shared. Privacy policy.

Related

• Sony A7S III corrupted MOV (similar XAVC family)
• What "MOOV atom not found" means
• How our recovery engine works

Upload your FX3 file →