Corrupted wav files

[patchworkmusic]

Hi All,

I have been having a nightmare with a recent session. I was recording in a Mac equipped studio, then editing at home on my PC. This was done using a Lacie drive, working on a mac (HFSJ) partition.

When i got the latest session home, i started work on it before i'd backed it up (silly mistake). Some errors stared appearing in pro tools, so i immediately backed up, but it was too late. Lots of files had gone missing from the drive.

After much panicing, searching the web and trying various different recovery software, i found one that worked, and i managed to salvage most of my files.

However, i now have a problem with at least 2 of my wav files, and of course these are the improvised, never can be repeated, vocals...

the files looked fine when first opened in pro tools, but when played back, there were glitches which consisted of full volume white noise over part of the files. When i either try to consolidate or open the files in another programme, the blocks of white noise become obvious, but in the original pt project, the wav images are fine.

has anyone come across a problem like this?

Is there any way i can salvage these files??

Thanks

[Chris Lambrechts]

start by deleting the wavecache file in the original session folder and regenerate the waveforms. If the file is corrupted it should show in the original session folder as well.

Create a new session and import the files - make sure you copy them on import to create new audio files.

Start there - it may not solve your issues but it will tell you a bit more on wether you can recover the original audio files or not.

Good luck

Chris

[patchworkmusic]

Thanks for the advice. The file seems to be corrupted on the drive. I don't suppose there's a way of restoring it?
Pro Tools still has the image of the uncorrupted wav, can this be used to help rebuild it?? Although i guess the image doesn't contain anywhere near enough data

Thanks

Toby

[Chris Lambrechts]

Hi Toby,

unfortunately it doesn;t work that way. The waveform display is cached (during recording or upon import or opening the files for the first time. All this cache does is make it easier on the system to open up the session the next time you need it. Kinda like the cache of your web browser for example.

Now it doesn't work the other way around. You cannot use that cached waveform display to recreate a waveform - even though in this case it would be nice

I would leave everything alone - matter of not doing more damage and bring the drive with the files back to the original system. See if you can still open them up over there.

Chris

[patchworkmusic]

I thought so.

I've tried on the original machine, and they're no different on there.

Seems I've lost those files.

What would cause this to happen, and is there any way of avoiding it in the future??

[albee1952]

Why it happened? Can't be sure but maybe the drive was disconnected while it was still writing something(which can happen even after Pro Tools is closed due to some OS message). Here's a "possible" solution. Create a new session but at a different sample rate(IOW, if the original session is at 48K, make the new one at 44.1K). Then Import Session Data and grab all the tracks from the original session. The Sample Rate Conversion on the way into the new session MIGHT iron out the wrinkles(its worth a try anyway as it has worked for me twice in the last year or so).

[GuinessCrowley]

Has any one found the cause of this "white noise burst" or "hash burst" file corruption issue? I've seen it before back in the day when Pro Tools still had Fade Files. The face files themselves would get corrupted. I also recall seeing it in 2014 in a mix for a film, and now I'm seeing it again.

Files are just randomly appearing with a loud burst of hash in them. Sometimes over audio, sometimes in the silence of a file. I've been trying to find a way to scan a drive for these files based on peak levels and the like and have had some positive results but the process takes too long to be used in a time sensitive situation. It's also not bullet proof enough to swear by.

As we would very much like to NOT have these files play back at our mix, especially when the Clients are there, I have been racking my brain trying to find the cause and also find a way to screen for these little audio time bombs.

At this point I am fairly certain that the files are corrupted during transfer, not locally by any program. If they are being corrupted by a program accessing and modifying them I think it's because it's still happening during transfer.... if that' s even possible.

Whether from drive to drive, from server to drive... any transfer is suspect. But is it the cable? Is it a drop in transfer speed between two devices? Is it a sudden burst of speed, can that happen? Is it a momentary drop in the connection altogether and the system fills in the gap with HASH instead of stopping transfer and alerting the user? I don't know.

Up until a few days ago I have only seen the short burst, about a second or two. But we downloaded a 17 min guide track and it was all HASH. And not a continuous bar of HASH, but a intermittent seres of segments. I should have checked to see if the Hash matched the actual wave forms of the good file but was rushed to solve the problem.

We deleted that HASHY guide track and re downloaded it from the server only to have the same thing happen. After that we went and downloaded the file on sever other systems to try and repeat the issue. All other system on the job downloaded a good file and were fine. We then went back to the original system and tried again. This time the file was fine.

I have no idea what causes this, but it is a HUGE problem. I'm not the only person I work with that has seen these files and no one seems to have clue about how to deal with them, save finding a good version of the file to replace the bad one.

Just a note, once you replace the file you session will sound find, however you either need to throw out your wave cache or redraw the waveform from within the session to make the HASH BRICK disappear from your files waveform. Even though you session is referencing a good file it is still using the old cached waveform data in the .wfm file. That's the other horrible thing about this issue. Pro tools can't tell the difference between them. The corruption process does not seem to change the files unique ID. This works both ways. You can see the HASH BRICK in your audio file on your track but it sounds fine, or the file can look fine but you will hear the HASH, an won't see the HASH BRICK until you redraw the files waveform manually.

Anyone know what cause this? I'm going to bring it to Avid Tech support next week and see if they can shed some light on it. Thanks.