Archiving

When you're in the world of tapeless post production, there are no tapes to have for archiving purposes. So you must back up your data on some sort of storage media. As I mentioned in a previous post, if you use Final Cut Pro to transcode to ProRes, you'll discover that your file sizes might not always correspond to the quality your camera recorded it at (i.e. the lowest quality 1440x1080 clips in AVCHD world become significantly larger than the highest quality 720p files). So if you back you your ProRes files you'll need a significant amount of storage space. But what about just backing up your AVCHD files?

This process is actually easy. What I'm doing is creating a folder on my storage RAID that is called AVCHD Card Back Ups. Within this folder I create a folder for each project. If I only used one card for that project, I'll simply copy the PRIVATE folder from the card to this project's folder. If there were multiple cards used, I'll create a set of folders with the simple name Card 1, 2, 3, etc. Copy each card's PRIVATE folder to their respective folders and that's it.

Be sure to keep a copy of your Final Cut project and one day, when the client asks for changes, you fire up that project, open up Log and Transfer, point it to appropriate PRIVATE folder(s) and re-transcode back to ProRes. The file naming scheme should remain the same. Obviously it's important to keep your original ProRes files named exactly how Final Cut named them, so when you re-transcode you can reconnect to the right files.

The end result is you back-up the significantly smaller AVCHD files and blow away the much larger ProRes ones. You'll be able to back up a lot more projects to the same disk as a result.

PS - I won't even get in to the idea that if you archive your files to a standard hard drive you'll need to be sure to power it up and let the platters spin periodically to prevent data loss. Do a google search and you'll see a lot of discussion about this fact.

Not HMC150 Related...

But I recently completed editing some spots for Martina McBride's upcoming "Shine All Night Tour". They've set up a channel over at You Tube to show off the spots and here's one of them (for some reason this doesn't really appear to be in "You Tube HD" even though I know they had the source files. Oh well, still looks okay):

Prores 422 ignores HMC150 record modes

You probably already know that the HMC150 records its 1080p and 720p PH clips at a maximum of 21Mbps. So technically these clips have the same data rate, or close to it. But if you use Final Cut to transcode these clips you'll discover they no longer remain at the same data rate. Final Cut's Prores essentially ignores the data rate of the camera original and only pays attention to the resolution. So that 720p clip's data rate at 24p becomes roughly 7.1 MB/sec and that 1080p 24p clip swells to 13.8 MB/sec.

Even worse, at least to me, is what Prores does to the camera's lowest quality setting, HE. These files are recorded to SD card at a tiny 6Mbps, but because the resolution of the clip is 1440x1080 and 29.97, the transcoded Prores clip swells to over 15MB/sec! That's right, a clip that is more than a third smaller than the highest quality 720p clip becomes twice as big as it after transcode.

The HE mode is perfect for long recording times, especially when the subject is a human who's giving a very long speech. You can squeeze many more hours of footage on your SD card and not have to worry about stopping to change out cards. But all of that space savings is thrown out the window once you transcode. I'll leave you with an example:

Clip - recorded using HE mode

Length is 1 hour and 13 minutes

AVCHD file size - 2.97 GB

Prores 422 file size - 65.92 GB!