Audio · exFAT audio media
Core Audio CAF: recover after an interrupted recording
What can I do with CAF recordings after a recording interruption?
Short answer
Often yes, because CAF anticipates this: its audio data chunk may carry a size of -1, meaning the audio runs to the end of the file, so an interrupted take can still open. Copy the file first and test the copy. If the header chunks are missing, repair needs the original codec settings.
The situation
CAF recordings is missing, too short or unreadable after power loss, a card error or an unsafe stop.
The file exists but the recording ended without being closed, so the values that normally describe its length were never written. CAF handles this better than most containers, because its audio data chunk may carry an open-ended size marker meaning that the audio continues to the end of the file.
01 / Diagnose
Work out what actually disappeared
When a recording stops unexpectedly, the chunks written at the start are usually intact while the closing update is missing. A CAF whose audio data chunk holds the open-ended size of -1 still plays, because decoders simply read to the end of the file. Trouble starts when the header chunks themselves never reached the card, leaving a payload with no format description.
The payload may have been written before duration fields, indexes, directory entries or closing structures were committed. For Core Audio CAF, this matters because CAF chunks can describe long recordings and several audio codecs
Check the last known path, trash and backups without writing to the original device.
02 / Protect the source
Preserve the best recovery chance
- 1
Power the device down cleanly, remove the card and do not let the app start a new recording in the same folder.
- 2
Copy the interrupted file to a computer drive and leave the version on the card untouched as a fallback.
- 3
Open the copy in a Mac audio application first; an open-ended audio data chunk often plays without any repair at all.
- 4
If the copy stays silent, note the codec, sample rate and channel count from the app and import the payload with those values.
Do not run a repair or a conversion directly on the card version, and do not let the operating system check the volume after the failure. A write that fixes the chunk sizes wrongly can cut the recording at the point the broken header suggests.
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.
Getting a truncated CAF to play again is file repair on a copy, done in an audio application. File Recovery Hero reads the exFAT card and exports the files stored on it, but it does not rewrite chunk sizes or reconstruct a missing audio description.
04 / Verify
Check the recovered content, not just its name
The take should play from its first second to the moment of the interruption and then stop, with speech or music intact rather than sped up or distorted. A recording that runs too fast or in the wrong channel order was interpreted with a wrong sample rate or channel count.
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 exFAT audio media be recovered in this situation?+
The file exists but the recording ended without being closed, so the values that normally describe its length were never written. CAF handles this better than most containers, because its audio data chunk may carry an open-ended size marker meaning that the audio continues to the end of the file. The result still depends on what remains readable on the source.
What should I avoid before scanning?+
Do not run a repair or a conversion directly on the card version, and do not let the operating system check the volume after the failure.
Does scanning write to my memory card?+
Your memory card is only read. Nothing is saved to it.
How do I know whether the result is complete?+
The take should play from its first second to the moment of the interruption and then stop, with speech or music intact rather than sped up or distorted.