Fast checksum with Red Drive...

[Etienne Caron]

If I plan to have 2 Red Drive on a small set and everytime that one do 30 minutes of shooting, i plan to go checking if the content is there with a laptop (without transfering). What kind of check can i do to make sure that everything is ok ? The crew is still shooting with the other Red drive and i'm gonna do the same procedure when this one reach 30 minutes of shooting. Data is transfered during lunch break and at wrap.

What kind of checksum (or what do you suggest) can i do to make sure that everything is ok on a RedDrive and without taking any longuer than 10 minutes to do ?

The goal is to detect problems before its too late during the day...

thanks

[Dylan Reeve]

Using a Mac or a PC?

I believe that RsyncX on OS X will perform a write verification as it copies, verifying that what was written is the same as what was read. There is possibly the chance of read errors, although interface-level disk checksum should catch that.

[Dj Joofa]

If you just want to compare files then you can use utilities such as sum/cksum and md5sum that come by default with OSX, and easily installed on a Windows based PC.

[Etienne Caron]

(ive change the title of the thread to make it more clear... my mistake, sorry)

My plan is NOT to copy. My goal is to do a check of the footage to make sure that everything is alright on the Red drive. It might be double-checking for frame drop (i think RedOne do it on camera) and do a visual check to make sure that the images is clean. It might be a check in Redcine by outputting a single .tiff of each shoot to make sure that the camera did well on capturing.

In resume, i have to do the part of the DIT's job that concern "checking the quality of the footage" without taking the consuming time of copying...

Copy will occure during lunch and at wrap (with write verification software).

thanks

[Dylan Reeve]

Well, nothing I'm aware of to do that yet. The RED camera knows when it dropped a frame. Beyond that, I don't know what you'd check. You have no known-good checksums to compare with anyway, so there's really nothing to compare.

Perhaps RED (or a third party when the format is available for others developers) may make a verification app that will verify the integrity of the actual data to conform to the format standard.

[Mike Prevette]

IMHO by "checking" your clips on a laptop you are opening yourself up to a greater possibility of failure, and mistakes to happen. I would just do the copy at that point as well, and alleviate a percentage of the failure that could happen.

[Etienne Caron]

Totally agreed with you Mike.

Have to see if there is a way to lock the Red Drive to be only written by the RedOne.

[donatello b]

(or what do you suggest) can i do to make sure that everything is ok on a RedDrive and without taking any longuer than 10 minutes to do ?"

how about you playback the shots after your shoot them ( using camera playback)?
or just play back the good takes ?

[Steen Dongo]

If you're on a Mac I believe you've allready got the right tools for doing a checksum. Use Disk Utility :)

Mount your disk on the Mac, open disk utility, click the proper icon in the left pane to select the disk and go to the "Images" menu. There you can select "Checksum" to test the validity of your data.

Actually I've been wondering if it isn't a good idea to convert the copied content from the CF cards to disk images (.dmg) ? That way you'd have a read only image for backup while making sure it's not possible to accidentally mess with the data ? Any thoughts ?

[Dylan Reeve]

Making images of the CF cards could be a very good idea, but it makes the data a little less accessible, unless you want to copy the data and images the cards.

Also you can perform a checksum of the drive, but with nothing to compare the checksum too, there is no way to get any idea of data validity. Also no way to determine the level of inaccuracy - a single bit different will completely change the checksum output without giving any indication as to what the problem is, or where it is.

[Mitch Deoudes]

Perhaps RED (or a third party when the format is available for others developers) may make a verification app that will verify the integrity of the actual data to conform to the format standard.

Or make the camera write a checksum to the media. This is apparently a planned feature - though not sure when. (Sorry, dylan - I couldn't resist. :bleh:)

In the meantime, pull up one of the smaller proxies, sit back & watch. This is actually a good argument for not shooting too long on one drive, or using CF cards.

[Etienne Caron]

in resume, just shoot no more than 30 minutes of content par Red Disk (or CF), copy only the Good take on back-up drive (or just one good take per shoot) and watch the smallest proxies to see if everything is alright (light, Red setting, etc..).

My goal is to be able to do some DIT stuff as a second assistant camera on small project and being able to run on set to do actors mark... copying all the project during lunch break and at wrap.

thanks

[Mitch Deoudes]

That sounds like a lot of work to be trying to do simultaneously with 2nd AC duties. From my experience, you probably won't have time for a visual verify of each shot if you're playing both roles. (And you don't want to be picking individual takes if you're running back and forth - just do a bulk copy & checksum.) Unless you've got enough drives to get yourself through to lunch every day, and time at lunch and at wrap for the visual verify.

Another idea: load up all the takes in RedCine at once, then watch footage a little bit at a time, pausing when you have 2nd AC work to do. It'll still be tight, but there will be a lot less thinking involved.

Of course, all of this depends on your shoot & how fast your crew is moving.

[Dylan Reeve]

Will REDCINE actually load a damanged clip, or will it throw up an error? Presumably the RED apps have the capability to verify the integrity of a file...

If that's the case then it's as simple as loading the clips into REDCINE. If they load, they are not broken - assuming of course that it does error on damaged clips.