How Sony video reconstruction works
The technical explanation, physical mapping, validation standards and limits.
How Sony writes video to the card
The recovery logic in plain English. No filesystem or video-container background required.
The important part: the neat MP4 you see later is assembled from information that was written to the card in a much less neat order.
Boxes and a packing list
The picture and sound are the boxes. Sony also records the sizes, order and timing needed to assemble them. When you press Stop, the finished MP4 index is written in the moov.
Sony leaves notes as it records
kkad bookkeeping is written among the video, audio and camera data. Those surviving notes can still describe the recording after the normal filesystem map is lost.
The cargo: your picture + sound
The packing list: how the recording fits together
Sony's real tables describe the exact sample sizes and order. A player uses those directions to know where one frame ends, where the next begins and how the recording should play.
The boxes are present, and the filesystem points to the finished MP4 and its packing information.
The boxes can still be present, but the normal route to the file may be gone. Finding video bytes is therefore only the first step.
Finding bytes is easy. Proving where they belong is the hard part.
The recovery engine tests candidate data against Sony's surviving bookkeeping and the complete original sample structure. Physical order can differ from playback order, and a logical piece can cross a filesystem allocation change.
Public testing: Joep van Steen (Arch Stanton on HDDGuru), of DiskTuna, supplied diagnostic bundles from his Sony ILCE-7SM3 / A7S III card during public testing. The diagnostics showed both AVC and HEVC recording layouts. AVC recordings predominantly used 820-byte kkad records and HEVC recordings 1492-byte records; those structural changes aligned with 40 AVC and 16 HEVC recordings detected independently. This is useful because it is a different body and layout mix from the FX3 HEVC recovery case. The tool detects the layout from the card; the user does not choose a camera profile.
“Can confirm it works on my Hellish card. Congrats, man!”
Joep van Steen · Arch Stanton on HDDGuru · DiskTuna
A recovered piece is accepted only when Sony's surviving recording metadata, the expected sample structure and the source bytes agree. If they do not, the candidate is rejected rather than guessed. Being nearby, codec-valid or successfully decodable is not enough.
A video that plays is not the same as a video that is proven.
Three kinds of recovery tool can look at the same formatted Sony card. The difference is what each one requires before it calls a piece of video yours.
1. Generic carving
Finds a file header and copies whatever follows it on the card. It assumes the recording sits in one solid run. Sony recordings usually do not, so the result is broken or scrambled.
Accepts: whatever is next.
2. Camera-aware fragment recovery
Disk Drill's Advanced Camera Recovery rebuilds recordings from camera metadata and matching fragments found across the card. It can recover footage that normal carving misses. See the detailed Disk Drill comparison.
CleverFiles also notes that reconstructed video can contain artifacts or missing segments. Its public documentation does not describe the same uniqueness test used here when more than one physical location fits.
Accepts: matching fragments that reconstruct the recording; preview helps verify the result.
3. Sony XAVC Recovery
Also works from Sony's own metadata, but a fit is not enough. A piece is accepted only when exactly one physical location satisfies every check below. If two locations fit, neither is called proven.
Accepts: the only possible fit. The evidence is written to a report.
And one other difference: it is free. No licence, subscription, upgrade screen or “we found 238 clips, now enter your credit card” moment. Download it, point it at a full-sector image, and use it.
Every recovered piece has to pass all of them.
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1 · Sony metadata
The piece must tie back to surviving Sony bookkeeping (kkad and moov) for a specific recording, not just look like Sony video.
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2 · Exact sample sizes
The bytes must match the recording's full list of frame and audio sample sizes, in order. Close is a failure.
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3 · Physical layout
The location must be consistent with how the card actually allocated space, including where one run ends and the next begins.
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4 · One candidate only
If a second location on the card passes the same checks, the mapping is ambiguous and is flagged Review instead of accepted. Why that differs from broader recovery.
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5 · Decoder check
The assembled video must decode correctly in context with its neighbours. This is the last check, never the only one.
A broader search may return more footage. This tool returns footage it can prove.
On some cards, a search-based product will list more video than Sony XAVC Recovery does. That is the cost of refusing to guess. Any file assembled without a uniqueness check can play and still contain frames from a different clip, a silent jump, or sound that belongs elsewhere, and a preview will not always show you where.
Here, every accepted recording comes with a CSV showing where each piece came from and why it was accepted. Anything uncertain is labelled Review or saved as .partial.mp4. For a wedding, client work or evidence, knowing which footage is certain matters as much as how much was found. About partial recoveries.
The tool is free and reads only an image, so there is no conflict in running it alongside another product and comparing results.
Source: CleverFiles, Meet the New Advanced Camera Recovery Module in Disk Drill 6.0, updated 27 May 2025. Descriptions of Disk Drill are paraphrased from that page. Disk Drill is a trademark of CleverFiles. This project is not affiliated with CleverFiles and has not tested every version of their product.
Same failure, independently.
In October 2025, Jeff Geerling documented recovering deleted Sony A6700 footage. He hit the same reconstruction problem from the other direction, without any connection to this project.
His case involved deletion, not formatting. It is cited here as independent evidence of the Sony reconstruction problem, not as evidence that a formatted card will remain recoverable.
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General recovery
PhotoRec found more than a hundred video files, but split the material into MP4 pieces and separate _moov.mov pieces. Gluing them back together did not produce playable video. Finding the pieces was not the same as reconstructing the recording.
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Video repair
He then tried untrunc with a known-good clip. It got partway: correct length, some smooth video, plenty of frozen frames. The data it was given still was not in the order the recording expected.
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What worked
A commercial product's normal deep scan still produced broken video. Its separate Sony-specific recovery mode worked. That is the useful bit: this is a Sony layout problem, not a generic MP4 carving problem.
Source: Jeff Geerling, Recovering videos from my Sony camera that I stupidly deleted, 23 October 2025. He is not affiliated with this project and has not endorsed or tested this tool.