Sizing a Shoot Day Before It Reaches the Shuttle Drive
On set, storage is a schedule problem long before it is a cost problem. The camera department speaks in megabytes per second — the unit every recording chart uses — while the drives on the offload cart are sold in terabytes. A DIT who cannot move between the two on the spot ends up guessing whether the afternoon block fits on the card already in the body.
MB = TB × 1000000. ProRes 422 HQ at UHD 29.97 runs about 88.4 MB/s, which is 88.4 × 60 = 5 304 MB per minute. Divide: 1 000 000 ÷ 5 304 ≈ 189 minutes of camera original on a 1 TB drive.What Eats the Budget on a Real Day
Cards Fill Before Batteries Die
Two Copies Is the Floor
Frame Rate Multiplies Everything
Both units here are the plain decimal kind, so the multiply is exact. What erodes the margin is container overhead, extra audio channels and that mandatory second copy — never the arithmetic.
Working Out How Much Drive the Day Needs
Four moves take you from a codec spec to a confident answer about capacity, and back again when the producer asks how long a given drive will last.
Enter the Drive or Card in TB
Type the capacity of the shuttle drive, RAID sled or card into the left field. Fractions are fine for card sizes — 0.512 for a 512 GB card — and a comma works as a decimal mark if that is how your keyboard is laid out.
Divide by the Codec's MB per Minute
Read the megabyte total, then divide it by the codec's MB/s figure multiplied by sixty. That gives recordable minutes. Working per minute rather than per second keeps the numbers in the range a call sheet is written in.
Copy the Figure Onto the Report
The copy button on each field hands over the bare number with no unit attached, which is what a camera report, a media log or a rename script expects. Ctrl+C inside a field does the same.
Reverse It From Scheduled Runtime
Both fields accept input and the swap button flips the direction outright. Multiply planned minutes by MB per minute, type that megabyte total into the right-hand field, and read straight off how many terabytes to send to the truck.
Acquisition Codecs: Data Rate and Runtime per Terabyte
Figures below are for UHD 3840×2160 at 29.97 fps unless noted, rounded from published codec data rates. Runtime assumes a completely full 1 TB — in practice you never fill the last few per cent of a drive, and the second copy doubles the requirement.
| Acquisition codec | Data rate | GB per minute | Minutes per 1 TB |
|---|---|---|---|
| H.265 long-GOP, 4K mirrorless | 12.5 MB/s | 0.75 GB | ≈ 1 333 min |
| ProRes 422 Proxy | 18.1 MB/s | 1.09 GB | ≈ 920 min |
| XAVC-I 4K intra-frame | 30.0 MB/s | 1.80 GB | ≈ 556 min |
| ProRes 422 LT | 41.0 MB/s | 2.46 GB | ≈ 407 min |
| ProRes 422 | 58.9 MB/s | 3.53 GB | ≈ 283 min |
| ProRes 422 HQ | 88.4 MB/s | 5.30 GB | ≈ 189 min |
| ProRes 4444 | 132.6 MB/s | 7.96 GB | ≈ 126 min |
| ProRes 422 HQ, 8K | 353.4 MB/s | 21.20 GB | ≈ 47 min |
Top to bottom that table spans close to thirty to one. Dropping one step down the ProRes ladder for an interview block buys back hours of drive life; stepping up to 8K turns a drive that comfortably held a day into one that holds a single long take.
Card, Sled and Codec Units in One List
Searchable dropdowns on both sides carry the whole data-storage set, so a card quoted in GB and a manual quoting megabytes per second meet on the same page without a second tab.
Typing Tolerant on a Bumpy Cart
Spaces are ignored and a comma is accepted in place of a decimal point, so a capacity copied out of a manual or a European spec sheet converts exactly as typed.
Runs Either Way Round
Enter drive capacity to get megabytes, or enter a megabyte total lifted from a media log to see what it occupies in terabytes — one button reverses the whole pair.
Numbers Fit for the Camera Report
Results carry up to eight decimals with thousands spaced for legibility, and the copy button yields the plain number so it drops cleanly into a log, a spreadsheet or a script.
Questions From the Offload Cart
How many minutes of ProRes 422 HQ actually fit on a 1 TB shuttle drive?
At UHD 29.97 the codec runs roughly 88.4 MB/s, or 5.3 GB every minute, so 1 000 000 MB divides into about 189 minutes — a little over three hours. Plan against something closer to 170 minutes in practice: file-system overhead, a drive that is already partly used and the sensible habit of leaving headroom all eat into it. At 59.94 fps, halve the figure again.
Should acquisition be ProRes or H.265 when drive space is the constraint?
The table shows the trade at its starkest: about 1 333 minutes of 4K H.265 per terabyte against 189 minutes of ProRes 422 HQ, a factor of seven. What you give back is grading latitude and edit responsiveness, because long-GOP material reconstructs each frame from its neighbours while an intra-frame codec stores every frame whole. Documentary and event work often live happily on H.265; anything heading for a serious grade justifies the extra drives.
Does the verify pass change how much space or time an offload needs?
Not the space, but very much the time. A checksum-verified copy reads every byte back after writing it, so budget roughly double the transfer duration. Two terabytes across a bus sustaining 250 MB/s is about 133 minutes to write and around 266 with verification — an offload started at wrap can still be running after the unit has left. Writing both destinations from one read of the card keeps that inside the day.
Do proxies need their own line in the shuttle-drive budget?
They need a line, but a small one. ProRes 422 Proxy at UHD runs about 18.1 MB/s against 88.4 for 422 HQ, so a full proxy set is close to a fifth of the originals — roughly 0.61 TB alongside 3 TB of camera files. The catch is that proxies are usually generated during the offload, competing with the verify pass for the same bus, so they stretch the window even though they barely dent capacity.
Why is the clip on the card bigger than the data rate predicts?
Published rates describe the video essence alone. On top sit the audio tracks — four uncompressed channels at 24-bit, 48 kHz add about 34.6 MB a minute — plus timecode, container structure, sidecar metadata and, on some bodies, an embedded look. Variable-rate codecs also overshoot their nominal figure on detailed or fast-moving material. Add five to ten per cent to any calculated total.
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