An ISO recording plan is a sum that is easy to get wrong in the rush before a show. Five recorders at 8 hours each, two copies and a drive that holds less than its label says can turn into a drive count nobody agrees on. This calculator does it in one place.
How to use it
Choose the codec. For H.264 and H.265, pick a bitrate preset or type your own from the encoder or recorder menu. For Apple ProRes, pick the flavour, resolution and frame rate, and the rate comes from Apple's published table. A short list of Sony XAVC S settings is included for handheld cameras, labelled as approximate.
Enter the number of recorders, the hours each one records, the copies you keep and the drive size. The default of two copies covers a working copy and a backup. The results show gigabytes per hour for one recorder, the total with copies, the drives needed and the minutes of recording each drive holds.
When to use it
Use it when pricing a job with ISO recording, when deciding between ProRes and a lighter codec for a long day, and when checking how many drives to take. A drive can hold the files and still be too slow to record them, so check the sustained write speed as well.
How it works
GB per hour for one recorder = Mb/s x 3,600 / 8 / 1,000. Dividing by 8 turns megabits into megabytes, and dividing by 1,000 turns megabytes into gigabytes. One copy is GB per hour x hours x recorders. The total is one copy x copies kept.
Usable space on a drive is its size x the fill percentage, 90% by default, to allow for formatting and a late take. Drives needed = one copy / usable space, rounded up, then multiplied by the number of copies, because each copy sits on its own drives. Sizes are decimal gigabytes, as printed on drives. Minutes per drive is usable space divided by GB per minute.
The Apple ProRes rates are the target data rates in Apple's ProRes White Paper for 1920 x 1080 and 3840 x 2160 at 25, 30, 50 and 60 frames per second. 29.97 and 59.94 fps use the 30 and 60 rows. Real rates vary with picture content, so treat them as planning figures.
The XAVC S figures are approximate bitrates from the Sony α6400 help guide. Other cameras differ, so use your own camera's manual. H.264 and H.265 rates depend entirely on the encoder setting you choose.
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