Question 1

My recorder lost power and the file shows 0:00. Is the recording gone?

Accepted Answer

Usually not. The sound was written to the card as it was recorded; only the length in the header was never filled in, which happens when you press stop. Drop the file here and the length is worked out from the file's size. Anything recorded in the last moments before the power went may be missing, as the recorder had not written it yet.

Question 2

The file is 0 bytes. Can it be repaired?

Accepted Answer

No: a file of 0 bytes holds nothing, because the card's file table was never updated with where the sound went. The sound may still be on the card itself. Stop recording to that card, and run a recovery program such as PhotoRec on it; the recovered pieces can then be repaired here, including ones that come back without a header.

Question 3

How do I know the right sample rate when the header is gone?

Accepted Answer

By listening. The bit depth and the number of channels can be worked out from the sound itself, but any rate plays - just at the wrong speed and pitch. Start with 48 kHz, which most recorders use; if voices are slow and deep, choose a higher rate, if they are fast and squeaky, a lower one. 44.1 kHz is usual for music made on a computer.

Question 4

Why is the repaired file RF64 rather than WAV?

Accepted Answer

A WAV header holds the length in 4 bytes, so it cannot describe more than 4 GB - about 6 hours of 24-bit stereo at 48 kHz, or much less for multitrack. Recordings longer than that are saved as RF64, the broadcast standard for long WAV files, which has room for the true length. Audition, Reaper, Pro Tools, Logic, Audacity and VLC open it; some simpler players do not.

Question 5

Does it fix clicks, noise or distortion?

Accepted Answer

No: it repairs the file, not the sound in it. To take out background noise, use Remove Background Noise; to cut a recording, the Audio Trimmer. For an .m4a recording from a phone that will not play, use Video Repair, which repairs those too.

Repair a WAV recording that will not play

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