Production · sports production cards and drives
sports production: check a backup size mismatch
Why is the backup from the sports production smaller than the source?
Short answer
Often the file counts differ because of helper files: action cams write low-resolution LRV and THM thumbnail files, other cameras XML sidecars, and a copy filter may skip them. Check whether the missing bytes belong to those or to real clips by comparing names and sizes per camera, with cards and backup left unchanged.
The situation
A copy exists, but byte totals or file counts do not match the recorded cards.
A backup that weighs less than the cards is not automatically incomplete. Helper files, cluster sizes and one failed large transfer all move the total in the same direction. The number to trust is the per-file byte size, not the folder summary the file manager shows.
01 / Diagnose
Work out what actually disappeared
Three causes look identical in a folder total. Action cams write LRV proxy and THM thumbnail files that many copy tools skip by design, so the file count drops while no footage is lost. Broadcast cameras add XML sidecars inside structures such as M4ROOT. A long take that crossed the 4 GB boundary on a FAT32 destination, meanwhile, fails as a whole file and removes gigabytes at once.
Hidden sidecars, failed large files, filters and allocation errors can all change totals. For sports production, this matters because the sports production combines several sources, takes and handoff steps that must be reconciled as a set
Check the last known path, trash and backups without writing to the original device.
02 / Protect the source
Preserve the best recovery chance
- 1
Leave both sides untouched: no repeat copy onto the backup drive and no deletion on the cards until the comparison explains every missing byte.
- 2
Generate a file list with names and exact byte sizes for each card and for the backup, then diff the two lists per camera folder instead of comparing totals.
- 3
Sort the differences into helper files, sidecars and real clips; copy the missing clips again from the card to an exFAT destination that accepts files beyond 4 GB.
- 4
Re-run the list comparison afterwards and store the result next to the backup, so the next handover starts from a documented count rather than an estimate.
Do not judge the copy by the size on disk that the operating system reports, and do not delete the cards because the totals look close enough. Cluster size alone shifts folder totals by a wide margin without a single missing frame.
03 / Choose the method
Match the tool to the source
For stable, readable exFAT, NTFS and FAT16/FAT32 or uncompressed IMG, DD, RAW and BIN images.
Unconfirmed exports are marked .UNVERIFIED.
A size comparison shows what is missing, not why a transfer failed. File Recovery Hero can scan the cards and the backup drive read-only if files have already been deleted, but it does not verify checksums, repair a truncated clip or read APFS and HFS+ volumes.
04 / Verify
Check the recovered content, not just its name
The backup is sound when every clip name on the card has a partner in the backup with the identical byte size, the differences left over are only LRV, THM or XML files, and a spot check from each camera plays to the end.
Keep the source until two verified copies exist. One working preview is not enough.
Sources and technical references
FAQ
Questions about this recovery case
Can sports production cards and drives be recovered in this situation?+
A backup that weighs less than the cards is not automatically incomplete. Helper files, cluster sizes and one failed large transfer all move the total in the same direction. The number to trust is the per-file byte size, not the folder summary the file manager shows. The result still depends on what remains readable on the source.
What should I avoid before scanning?+
Do not judge the copy by the size on disk that the operating system reports, and do not delete the cards because the totals look close enough.
Does scanning write to my memory card?+
Your memory card is only read. Nothing is saved to it.