Raw video files grow quickly because file size is bitrate multiplied by recording time, and bitrate rises with pixel count, frame rate, bit depth, chroma information, and the amount of compression. Raw formats preserve sensor data and avoid much of the compression used by delivery codecs, so every additional minute can add many gigabytes.
The practical formula is:
file size in decimal GB = bitrate in Mb/s × seconds ÷ 8 ÷ 1,000
For one hour, GB/hour ≈ Mb/s × 0.45. Vendor rates are usually targets or approximations, and constant-quality codecs can vary by scene, but the formula explains the result.
Resolution multiplies pixels
ITU-R BT.2020 specifies 3840×2160 for 4K UHD and 7680×4320 for 8K UHD. The 8K frame has four times as many pixels. At a matched codec and frame rate, bitrate therefore tends to rise by roughly four times. Apple's target data rates show this directly: ProRes 422 HQ at 24p rises from 754 Mb/s at 4096×2160 to 3,017 Mb/s at 8192×4320.
Pixel count is only the first multiplier. A theoretical uncompressed 3840×2160, 10-bit, 4:4:4 signal stores 30 bits per pixel. At 24 frames per second:
3,840 × 2,160 × 30 × 24 ≈ 5.97 Gb/s
That is about 2.69 decimal TB per hour before compression. It is derived ceiling arithmetic from a stated parameter set, not a camera recording format or a practical file-size promise.
Frame rate, bit depth, and chroma add data
More frames mean more pictures each second. Apple lists ProRes 422 at 4096×2160 at 503 Mb/s for 24p and 1,257 Mb/s for 60p. Slow motion can therefore multiply storage even when resolution and codec stay fixed.
Bit depth increases the values recorded for each component. Chroma sampling determines how much color information is retained: 4:4:4 carries more samples than 4:2:2 or 4:2:0. The exact effect depends on the format, so “10-bit 4K” is still not enough information to size a shoot.
Codec is the largest practical lever
Compression decides how much of that source information becomes stored data. Intra-frame formats compress each frame independently and are often easier to edit but larger. Long-GOP formats share information across frames and can be much smaller, with different decode and post-production trade-offs.
| 8K 24p format | Published bitrate assumption | Theoretical volume | |---|---:|---:| | XAVC H Long, 7680×4320 | Sony 520 Mb/s | 234 decimal GB/hour | | XAVC H Intra SQ, 8192×4320 | Sony 704 Mb/s | 317 decimal GB/hour | | XAVC H Intra HQ, 8192×4320 | Sony 1,056 Mb/s | 475 decimal GB/hour | | ProRes 422 HQ, 8192×4320 | Apple target 3,017 Mb/s | 1,358 decimal GB/hour |
These values use named vendor modes, resolutions, and published bitrates; they are not interchangeable quality rankings. Practical files can differ from bitrate arithmetic because of variable-rate encoding, audio, metadata, and containers.
“Raw” also covers different designs. ARRI describes ARRIRAW as Bayer sensor data that must be debayered into an image. ARRI's lossless HDE encoding produces files at about 60% of original ARRIRAW size while remaining bit-for-bit lossless. Blackmagic RAW constant-quality modes intentionally have no fixed upper data rate, allowing complex frames to use more data. Therefore, there is no universal “raw equals X GB per minute” figure.
Duration is the silent multiplier
Once settings are chosen, growth is linear with time. Canon's published EOS R5 table lists approximately 18.7 GB per minute for an 8K RAW mode—about 1.12 TB per hour. A ten-minute take is manageable in isolation; repeated takes, multiple cameras, audio, proxies, and protected copies turn a shooting day into several terabytes.
This is why storage planning starts before the shoot. Record the exact codec, mode, resolution, frame rate, and expected rolling time. Multiply the vendor bitrate by duration, then add explicit allowances for audio, sidecars, proxies, backups, and free-space headroom. Do not use a generic “4K per hour” result.
Control size without losing the workflow
Choose the acquisition codec from delivery, VFX, color, and archive requirements rather than file size alone. Generate lightweight proxies for editorial, but preserve the originals needed for conform. Use vendor-supported lossless encoding where appropriate, avoid rolling unnecessarily, and separate required takes from caches and temporary renders.
The related 4K storage table and 8K storage table provide concrete planning values. Once the measured package is known, use the transfer calculator and the remote-footage workflow to plan movement.
Where TeraAirlift fits
When a shoot day reaches terabytes, size becomes a transport problem as well as a storage problem. TeraAirlift provides a Windows desktop queue with progress, ETA, history, diagnostics, and SHA-256 integrity verification for large file and folder delivery. Those controls improve visibility; they do not change the codec's bytes or guarantee transfer speed. See the post-production workflow for the operational context.
