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First, we need to understand what we’re dealing with here. How big are uncompressed files, really? To calculate the uncompressed file size and data rate, use this method:

How to Calculate Size and Data Rate of Uncompressed Files


Where
Resolution = Horizontal Resolution x Vertical Resolution
Color Data = Color Bit Depth per Channel x Total Number of Channels
Metadata Factor = Overhead for metadata, usually 2-3% but I add 5% for safety
Chroma Factor = (Y’ + Cb + Cr)/12

E.g., a 16-bit uncompressed 1080p24 4:2:2 file will have the size = (1920x1080x16x3x1.05)/(1024x1024x8) = 12.46 MB per frame.

The data rate for such a file = 12.46 x 24 fps x 0.667 = 200 MB/s

Note: The chroma factor is added in the data rate formula because a full raster image file will reserve space for all three color components – R, G and B, regardless of how it has been sampled.

Note: Instead of ‘1024’, you can also use ‘1000’ instead for additional safety – we all know how a few manufacturers love to fudge their numbers!

Try it on your TIFF and DPX files and see for yourself!

Now that we know how to calculate uncompressed file sizes we are in a better position to estimate how much data we are going to use on a particular project. But before we get into that, it might be a good idea to estimate the cost per GB and cost per TB of footage.

Finding the Cost per GB/TB

A 1TB SATA 6Gb/s 3.5″ Hard Disk Drive costs about $100 ($0.09/GB).

A 3TB SATA 6 Gb/s 3.5″ Hard Disk Drive costs about $150-$180 ($0.05/GB).

A G-Technology G-RAID 6 TB Dual External Hard Drive costs about $517 ($0.08/GB).

All in all, from my calculations, I figure the price to buy and maintain hard drives to be at the rate of $0.12 per GB, as long as one is working with terabytes of footage. This includes enclosures, cables, maintenance, controllers, etc.

Now that we have a limit to how much a GB costs, we can figure out the expenses involved in working with uncompressed footage.

The Cost per Project

Different projects have different storage requirements. Some of the factors that determine this are:
1. Length of final product (30 sec commercial to 3 hour feature)
2. Film or digital (Shooting ratios for film are much lower that digital video)
3. Single camera or multi-camera
4. Scripted or Un-scripted (Documentaries that focus on uncontrollable events take a long time to shoot)
5. Number of shooting days

Traditionally, for feature films, the shooting ratio has been around 5 or 10:1. On the other end of the spectrum, multi-cam reality shows and documentaries can go up to 500:1. In the latter case a 2 hour documentary or show at 500:1 can have 1000 hours of footage.

We can break down our calculations thus (Click to enlarge):

As you can see, the costs of storing uncompressed footage goes out of hand quite quickly – and this is for just one copy of the footage! If you take backups into consideration, and multiple files moving between visual effects companies you can clearly see how a 4K movie can go into the millions just in storage costs.

Even storing a 4K master in 32-bit at 24 fps will cost $5,000 for two copies.

I hope by now you have a clear idea of the storage costs involved in working with uncompressed data. If you want to move all this data in real time, the costs of computer systems will increase as well. Plan wisely!

Exclusive Bonus: Download my free cheatsheet on when to choose a Steadicam, Gimbal or Handheld Rig for those camera motion shots (PDF file optimized for mobiles and tablets).

4 replies on “The Costs of Working with 2K and 4K Uncompressed Footage”

  1. Chroma Factor explanation is little bit confusing. In the example, the frame size (in MB) is calculated using a 4:4:4 chroma sampling (even if the real sampling is different). That’s why there is not any “Chroma Factor” on that formula. IMO there should be even if the value es 1. However in the “Data Rate” formula, there is a “chroma sub-sampling” process to 4:2:2.

    Actually that’s the part where still images are different to moving pictures. Sub-sampling from 4:4:4 to 4:2:2 is kind of “compression” because the eye is less sensitive to colors than (white) light, even less in moving pictures, so some color information is remove for the sake of data rate.

  2. Pingback: How to Work with Redcode RAW R3D Footage | roberto cimatti

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