Backup and Archive SDHC Cards

September 12, 2009

Backup and Archive SDHC

Continuing with my backup and archiving strategy, one of my goals was to get a grip on the growing number of SDHC cards I use with my video cameras; mainly my Canon HF10.  I’ve been ordering about five 4GB cards every couple months.  Besides being small and easy to lose, they are difficult to label and therefore difficult to manage from an archiving perspective.

There are a few options to deal with this.  I could import the video from the cards into iMovie or Final Cut Express and reuse the cards, but there are a few disadvantages to doing this.  First, the imported AVCHD video files are huge compared to their natural compressed state on the SDHC card.  Second, you never know when you need to get the video back on the camera in its original form.  Another option is to use iMovie’s archive feature, which copies the contents of the card to a folder on your hard drive, but I found a better solution that provides many advantages.

I theorized that I could create an image of the SDHC card so I did a quick Google search to see if someone was doing this already.  I found this post on Scoopz Blog which is exactly what I was looking to do.  The short story is, using Apple’s Disk Utility, I can make a disk image (DMG) of the SDHC card.  Here are a few advantages to this technique as opposed to iMovies archive feature:

  • Manage single DMG file versus directory structure—I’m copying the resulting DMG file over to my NAS (running FreeNAS), then letting FreeNAS copy to an additional external FireWire drive using RSYNC.  With the intricacies and caveats of multiple file systems, fewer directory structures and increased control over file naming becomes really important in backup/archive strategies.
  • Mounting image acts like SDHC card or camera—When I choose to remount the DMG file, iMovie and Final Cut Express recognize the mounted drive as if I just plugged the camera into my Mac or inserted the SDHC card into a reader.
  • Copy DMG back to SDHC card—Scoopz gives a very good reason why this is important.  In his case, his camera records 5.1 sound; however, iMovie can’t handle all of those audio tracks and reduces to stereo.  Getting the raw data back on the camera improves options for future usage.  There’s no messing with formatting the SDHC card the way the camera expects as the DMG handles that by its nature.

For a tutorial on how to make an image of your SDHC cards using Disk Utility, read Scoopz post.  As for naming the DMG files, I used a combination of camera, video format and a sequence number.  For example, canon_avchd_0001.dmg.

Now that I’m confident my raw video footage is being archived, I need to focus on labeling/logging the video in the event I need to find that one clip I want to use without resorting to mounting every DMG for browsing.  After researching a few tools to do this sort of thing, I decided that in the event I needed to recover this data, one less tool to install and configure the better.  And while I’m not 100% sold on the solution I came up with, I chose to do something now so I could proceed in archiving all of the SDHC cards on my desk rather than waiting for the perfect solution to present itself.

I decided to use a spreadsheet (something searchable) with a few columns:  REEL (the dmg file name), CAMERA, FORMAT, DATE, SUBJECT, KEYWORDS and CLIP THUMBNAILS.  I used iMovie’s import feature to grab screen shots of the clips for a visual reference.  I doubt this process will scale, but I’ll see how it goes.  Here’s an example of the spreadsheet I created using Numbers:

Video Log

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