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Gear / Technical Help => Post-Processing, Computer / Streaming / Internet Devices & Related Activity => Topic started by: seethreepo on November 09, 2021, 10:19:41 AM

Title: zero byte files / .chk
Post by: seethreepo on November 09, 2021, 10:19:41 AM
 https://drive.google.com/drive/folders/1MTUk69_buDvxPhfAEpBiezTaTiV5mTJF?usp=sharing

above is a folder of CHk files. I recorded a show but had battery problems and files didnt save correctly.  I read and re read the zero byte threads but cant get anything to work.  Could someone who is a little more savvy try and write new wav headers to these files for me? 
The files are  48k 24bit wavs. 

any help super appreciated!
Title: Re: zero byte files / .chk
Post by: if_then_else on November 09, 2021, 11:37:16 AM
I've tried a couple of repair tools (fixwav, qwavheaderdump on Linux, Audacity's raw import feature and Samplitude's dump import feature on Windows) and none of them worked.
Closer inspection of some of the CHK files with a hex editor revealed that their contents are all zeroes. Many 0's, actually. You might want some ones in between.  ;)

https://dilbert.com/strip/2005-05-08 (https://dilbert.com/strip/2005-05-08)
Title: Re: zero byte files / .chk
Post by: beatkilla on November 09, 2021, 11:41:23 AM
I also tried several ways with no luck.

Audacity RAW opened it but there was no sound or waveform?
Title: Re: zero byte files / .chk
Post by: if_then_else on November 09, 2021, 11:46:24 AM
Like I wrote: The content has been wiped. The binary files contain nothing but zeroes.

The copy process (from your SD card to disk) might not have worked as expected. Maybe use a low-level copy tool like dd to clone the content of the SD card before you try again. Assuming the SD card hasn't been formatted yet.
Title: Re: zero byte files / .chk
Post by: seethreepo on November 09, 2021, 02:05:11 PM
Thanks for the efforts  everyone. I truly appreciate it.  Not the outcome I was hoping for   but I guess I'll chalk it up to stuff happens. 
If anyone wants the parts I was able to record /successfully save.  I'm happy to upload.   
Title: Re: zero byte files / .chk
Post by: if_then_else on November 09, 2021, 02:22:50 PM
I wouldn't throw in the towel yet.

(1) Clone your SD card to an img or iso file (using dd on Linux or a tool like Win32Imager on Windows). That way you do not risk your master files by trying to salvage them.
E.g.: https://beebom.com/how-clone-raspberry-pi-sd-card-windows-linux-macos/ (https://beebom.com/how-clone-raspberry-pi-sd-card-windows-linux-macos/)
(2) Mount the cloned img file in your OS (like you'd do with a DVD or CD)
(3)  Try to fix them there. E.g. using Audacity's RAW import feature or fixwav.
(4) Whatever you do, don't mess with the original files on your CD card.

I think the problem with the files you've uploaded on Google is that not only the file headers are missing but that the copy process itself has rendered the copied files useless.
Title: Re: zero byte files / .chk
Post by: rigpimp on November 09, 2021, 04:27:51 PM
These ARE NOT .wav files.  .chk files are fragments of corrupted data.  It is not likely that the homegrown utility we have used here will work since it is not a headerless .wav file.

I would try a couple of things but as noted above clone/image the card first. so you have a backup image of the whole thing.

Then working with the card I would personally try an NTFS/FAT disk recovery solution.  Your goal here is to restore the data to your card first.  Simple free tools I have has success with include, but are certainly not limited to, Recuva.  Man, that program alone saved my ass as the estate archivist about 8 or 9 years ago.  I am also a HUGE fan of Stellar Phoenix NTFS/FAT tools, not cheap but also found files deleted 6 months prior.

You can find some tools online that will take the bits of corrupted data (.chk's) and turn it back into a common file type like .jpeg, etc.  UnChk is one that is pretty commonly used.  It helps to have the entire FOUND.000 folder, intact.

Good luck!