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Audio-editing software

Spiderous

pfm Member
Good morning all,
a bit of a strange one this. Amongst other crappy aspects of my job I am my employer's Data Protection Officer. My organisation records telephone calls into its Contact Centre and also supports the recording of noise nuisance for enforcement purposes. In certain circumstances these recordings (or parts of them) may be disclosable under a Subject Access Request. To disclose them I may need to redact them. Can anyone recommend any suitable software for this purpose. The only provisos are that it must be cheap, and it must be VERY easy to use.

Thanks,
Ian
 
I assume the recordings are already in digital format. Anyway look into 'Audacity'. Free and much used by all and sundry.
 
super easy to use, to redact a segment just drag select that part of the waveform and perform a gain transform to 0db.
 
super easy to use, to redact a segment just drag select that part of the waveform and perform a gain transform to 0db.
I think you mean -inf dB, i.e. set all sample values to zero. Alternatively, it should be fairly easy to overwrite the selection with a tone.
 
super easy to use, to redact a segment just drag select that part of the waveform and perform a gain transform to 0db.
Would it be possible to reconstruct the original waveform (eg, by some sort of ‘undo’ process). To ensure proper redaction, you’d want to ensure any metadata, or file history that retained the original waveform, didn’t go out with the redacted copy.

(I’ve seen too many ‘redacted’ documents where the ‘redaction’ process was simply to create black text on a black background. A simple change of either text, or background colour and, hey presto!, no more redaction...).
 
Would it be possible to reconstruct the original waveform (eg, by some sort of ‘undo’ process). To ensure proper redaction, you’d want to ensure any metadata, or file history that retained the original waveform, didn’t go out with the redacted copy.
As long as the samples in the redacted section are replaced (with zeros, a tone, or whatever) rather than attenuated or mixed with something, it will be impossible to recover the original. I've never heard of an audio file format containing a second copy of the data, but metadata could of course mention e.g. names or locations that should be kept secret. Definitely something to watch out for.
 
As long as the samples in the redacted section are replaced (with zeros, a tone, or whatever) rather than attenuated or mixed with something, it will be impossible to recover the original. I've never heard of an audio file format containing a second copy of the data, but metadata could of course mention e.g. names or locations that should be kept secret. Definitely something to watch out for.
I’m thinking of the analogy of a Word document, that retains a record of the last ‘n’ changes so you can revert to a previous version should you choose to. The file doesn’t contain multiple, nested, versions, but rather the file history of changes since it was created. These are in metadata. I’d want to be sure the recipient of a file couldn’t simply hit the ‘undo’ button repeatedly and thus recover the changes.
 
I’m thinking of the analogy of a Word document, that retains a record of the last ‘n’ changes so you can revert to a previous version should you choose to. The file doesn’t contain multiple, nested, versions, but rather the file history of changes since it was created. These are in metadata. I’d want to be sure the recipient of a file couldn’t simply hit the ‘undo’ button repeatedly and thus recover the changes.

I'm not a user of Audacity but in Cubase, you can render the .wav to effectively a new file with, in theory, no legacy metadata from the original. Perhaps it's an option in Aduacity?
 
I'm not a user of Audacity but in Cubase, you can render the .wav to effectively a new file with, in theory, no legacy metadata from the original. Perhaps it's an option in Aduacity?
There is an "export" function, if memory serves.
 
IIRC Audacity lets you remove metadata. However I can't be sure as I never add any in the first place!

And wrt redaction, I'd assumed that simply snipping out the relevant sections would do. But does the OP require blanks to indicate where parts have been removed?
 
IIRC Audacity lets you remove metadata. However I can't be sure as I never add any in the first place!

And wrt redaction, I'd assumed that simply snipping out the relevant sections would do. But does the OP require blanks to indicate where parts have been removed?
Again, it would depend on whether the snipping out could be reversed by some ‘undo’ function.
 
Again, it would depend on whether the snipping out could be reversed by some ‘undo’ function.

If saved as a wave file the data would no longer be in the file. The file would have a shorter playing duration and there might be audible 'jumps' as the cut points as when a bad tape splice has been carried out. So the question would be if these matter, or if the recipient should have the gaps as silences so they can tell where parts have been removed, and how long they were.
 
Given the question it seems logical to wonder if someone has already written a 'redact' function for use when editing with Audacity. This could simply zero the relevant series of samples. Anyone know? If not, I'd assume it would be trivial for someone who knows how to write a plug-in.
 
If saved as a wave file the data would no longer be in the file. The file would have a shorter playing duration and there might be audible 'jumps' as the cut points as when a bad tape splice has been carried out. So the question would be if these matter, or if the recipient should have the gaps as silences so they can tell where parts have been removed, and how long they were.
You would insert either silence or some other noise for the period of the redaction.
 
If you save as an Audacity project you can undo changes.

If you export the audio to a wav file (which is what you would want to do) you can't undo the edits.

I just edited a wav file in Audacity and double-checked.

I record regularly with Audacity and this is completely correct - the exported file (Aiff, mp3 etc) is in effect "original". As for meta-data / tags, this is also set by the user during the audio export process so whatever the user wants to add or remove can be done easily.
 


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