How to fix a corrupted Sony video (XAVC S, XAVC HS)

By the FixMP4 engineering team · Updated October 9, 2026 · Tested on real H.264, HEVC and AAC recordings

Sony Alpha, ZV, FX and Handycam cameras record XAVC S (H.264) and XAVC HS (H.265) in MP4 files. If a clip will not open after the battery died or the card was pulled, put the card back in the same camera and power on: many Sony bodies show a "recovering data" message and close the file themselves. If that does not work, rebuild the MP4 index from a short reference clip recorded with the same file format, record setting and frame rate. The FixMP4 repair tool runs that rebuild in your browser with a free preview. AVCHD (MTS) is a different format and is not supported.

Sony video formats at a glance

Most current cameras (a7 III and IV, a7S III, a7C, a6400 to a6700, ZV-1, ZV-E10, ZV-E1, FX3, FX30) default to XAVC S or XAVC HS in MP4, which is the supported case.

Why Sony clips break

As with most cameras, Sony writes the video frames first and the MP4 index, the moov atom, when recording stops. A battery that empties (the small NP-FW50 drains quickly in 4K), an overheating stop, a card removed while the access lamp is lit, a full card, or a card too slow for the bit rate leaves a file without an index. Sony bodies also keep a database file on the card; a damaged database can make clips disappear from playback in camera even though the MP4 files are fine on a computer.

Step 1: let the camera recover

Insert the card into the same camera, power on, and wait. If the camera shows a message about recovering data or repairing the image database, let it finish completely. Power off normally and copy the PRIVATE/M4ROOT/CLIP folder (where XAVC files live) to a computer. Do not format the card yet.

Step 2: copy everything, including XML sidecars

Each XAVC clip has a matching XML file with metadata in the same folder. Copy both. The XML is not needed for repair, but editors such as Catalyst Browse and some NLEs use it.

Step 3: record a matching reference

On the same camera, record ten seconds with the same:

• File format: XAVC S 4K, XAVC S HD, XAVC S-I or XAVC HS.
• Record setting: frame rate and bit rate (for example 25p 100M, 50p 150M, or 4:2:2 10-bit).
• Picture profile / S-Log / HLG, which changes bit depth and profile on many bodies.
• Super 35 / APS-C crop if used.
• S&Q motion (slow and quick) settings if the clip was recorded in S&Q.

If you cannot remember, read the settings from an intact clip with MediaInfo or VLC's codec information. More guidance: how to choose a reference file.

Step 4: rebuild the index

1. Open the repair tool and add the broken MP4 and the reference.
2. Check the free preview: motion should be smooth and colours correct for the profile you used (S-Log footage looks flat by design).
3. Export the full repaired clip with a subscription.

Audio on Sony cameras

Many XAVC S and XAVC HS modes record linear PCM audio (LPCM), not AAC. FixMP4 rebuilds AAC audio only. With LPCM, the audio chunks sit between the video chunks and the scan has to step over them; depending on the layout the result can range from video recovered without camera audio to a repair that cannot separate the streams cleanly. The free preview shows you which case you have before you pay anything. If you also recorded audio externally or on a lavalier transmitter, sync that in your editor. Some ZV and vlogging modes and a few compact cameras record AAC; check your intact clips with MediaInfo to see which applies.

What to expect

• The video up to the moment the camera stopped writing, usually all but the last second.
• No embedded timecode or XML metadata for the rebuilt clip.
• Clips from intra-frame XAVC S-I are especially robust; damaged spots affect single frames only.

Proxy recordings

If you enabled proxy recording, the camera also wrote a small HD proxy in a SUB folder. A proxy is often closed at a different moment, and is a useful fallback or a reference for timing.

How the rebuild works

FixMP4 reads the media data of the broken MP4 directly from your disk, finds each H.264 or HEVC frame by its NAL unit structure, and measures it. It takes the parameter sets that describe the stream (resolution, profile, bit depth) from your reference clip, recreates timestamps from the frame rate, restores B-frame ordering and the keyframe table, and writes a new index in front of the untouched media data. No frame is re-encoded, so S-Log grading latitude and image quality are exactly what the camera recorded.

Common mistakes

• Using a reference recorded in XAVC S HD when the clip was XAVC S 4K, or in 8-bit when the clip was 10-bit 4:2:2.
• Formatting the card before letting the camera try its recovery.
• Repairing a file copied from the camera over USB while the camera was still writing.

Prevention

• Use V90 or CFexpress Type A cards for high bit-rate XAVC S-I and HS modes.
• Format the card in the camera, not on a computer.
• Watch the overheating setting (Auto Power OFF Temp) and battery level on long takes.
• Wait for the access lamp to go out before opening the card door.

Related guides

• Fix Canon video and fix Nikon video
• Repair an MP4 file
• All device guides

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