Data rate

Simulator

What a shooting day actually costs in cards

Every codec spends a certain number of bits on each pixel of each frame. From that one number, the size of a card, the number of cards and the hours somebody will spend copying them all follow.

• Bits per pixel

  Every codec boils down to how many bits it spends on each pixel of each frame. Multiply that by the pixel count and the frame rate and you have the data rate. Everything else on this page is arithmetic from there.

• Why raw is not always huge

  Compressed raw at 8:1 can be lighter than ProRes 422 HQ, because ProRes is spending bits on three full colour channels while raw is still a single-channel sensor read. Raw is big when it is lightly compressed, not because it is raw.

• Frame rate is linear

  Doubling the frame rate doubles the data. A 120 fps ramp does not cost a little more card, it costs five times the card of 24 fps, for the same running time on the timeline.

• The 3-2-1 habit

  Three copies, two kinds of media, one of them elsewhere. In practice that means every card is written at least twice before it is wiped, which is why offload time matters as much as card capacity.

• Offload is the bottleneck

  A day's footage that fits on two cards can still take hours to copy and verify twice. Work out the offload time before you choose the codec, not after the cards are full.

• These are estimates

  Real rates vary with the camera, the firmware, the sensor mode and, for the long-GOP codecs, with how much the picture is actually moving. Treat the figures here as a planning estimate with headroom, not a guarantee.