Blackmagic Forum

Has anyone experienced drop out with their files? Not dropped frames, horizontal blocks (kind of like DV tape dropout). This is with pro-res and DNXHD. I don't think it's the camera, I think it's when I copy files onto my computer - like the ssd isn't reading the file properly, or the data is getting a bit corrupted during the transfer (I've copied the same file multiple times and the drop-out occurs on different frames). I'm using an intel 335 ssd from the approved list.
Any advice welcome.

Try using a program like shot put pro to do checksums to see if the data is being copied correctly.

Or you can do an MD5 hash on the source and destination file manually to see if the files are exactly the same.

Just out of interest sake, does the corrupt image look like this ?

https://www.dropbox.com/s/cn23kn87pyrij ... 1%20AM.png

Hi both, thanks for responses.

will try checking files as you suggest.

My "drop-out" isn't as extreme as that - it's usually a thin bar (maybe 10-15 pixels deep), sometimes black, sometimes like a negative version or shifted horizontally, occasionally it has a kind of digital noise pattern like you used to get with dirty heads on a DV deck???

carthorseDC wrote:...occasionally it has a kind of digital noise pattern like you used to get with dirty heads on a DV deck???

This may not relate but I wanted to throw in my 2 cents-

I experienced something similar to this in FCPX with another camera and it turned out it was bad RAM on my computer. I was transferring footage from an SD card and it would drop a series of frames randomly.

I guess the theory here is that the footage is caching through the memory first and hitting these snags because of failed blocks, etc.

EDIT- for the record, I can't see the dropbox file as I'm at work so I'm basing this purely off conjecture. Feel free to flame me if I'm off base.

Well I did the checksum test - the files when transferred are indeed different to the original on the ssd, and also if I transfer the same file twice, they are different to each other.

Thanks for your suggestion Dustin, but I have tried transferring on both a PC and a mac with similar results, so for the moment I would probably discount bad RAM...

At the moment I'm thinking either some kind of problem with the SSD, or possibly a dodgy dock.

I'm going to try round-tripping a file - to the SSD and back again and do the checksum test with these files.

Have now tried transferring files (using USB2 sata dock) on two computers at work -

Mac pro with 10.6 and a pc running windows 7 (my home computers are pc running XP and a PPC G5 running 10.5) -

SSD formatted ex-fat: Home Pc (XP) - lots of errors, Work Pc (W7) -lots of errors, Work Mac (intel 10.6) - only one error on one clip, that I could determine...

SSD formatted HFS+: Home Pc (XP) - lots of errors, Home Mac (PPC 10.5) - lots of errors

My thoughts are that it might be to do with USB drivers in conjunction with the SATA dock??

I would appreciate any further thoughts or suggestions anyone might have...

By the way, other than this frustration I am loving the camera - even using the compressed formats the image is both superb and "malleable" in post...

Just to update this - I think it was the dock that was causing the problem.

They say "buy cheap, buy twice" but paradoxically I tried with a cheap SATA to usb cable from amazon (£7) and everything copied flawlessly...

thanks to everyone for their suggestions.

We had a similar issue with a bad dock. Although we weren't getting any weird images, we were just getting extremely slow read write times and crashes and copy failures. Checksums were not matching. At first we thought it was problems with the drive, but then switched docks and everything was fine.

It was a U-speed e-sata & USB 3 dock. We had one that we had used with no issues, had just bought a second identical model which was the culprit. They exchanged our defective dock immediately without argument and both have worked flawlessly since.