How Frame Rate Changes BRAW Storage and Recording Time

Frame rate changes BRAW storage almost linearly. If resolution and compression remain constant, recording 60 frames each second creates roughly twice the data of 30fps and 2.5 times the data of 24fps. High-speed acquisition can therefore become the largest storage multiplier on a shoot.

The key is to calculate from capture frame rate, not playback or timeline frame rate.

The frame-rate multiplier

Choose a baseline and divide the new rate by it:

Storage multiplier = new capture fps ÷ baseline capture fps

Relative to 24fps:

This proportional model is a strong planning starting point. A camera may use a different sensor window, crop, maximum quality setting, or recording implementation at high speed, so verify the exact supported format.

Capture time and timeline time are different

Suppose a camera captures 60fps for ten real-world seconds and the editor conforms it to a 24fps timeline. The clip contains 600 frames. At 24fps playback, those frames last 25 seconds.

The camera stored ten seconds at the 60fps data rate. The timeline gained 2.5× slow motion, but storage was consumed during the original ten-second event.

This creates two useful ratios:

• Acquisition storage: based on 60 captured frames per second
• Playback duration: 60 ÷ 24 = 2.5 times the real duration

Do not multiply storage by the slowed playback duration again. The captured frame count already contains the cost.

Example: normal speed plus high speed

A commercial plans:

• 90 minutes recorded at 24fps
• 20 minutes recorded at 60fps
• Same resolution and BRAW compression
• 500GB per hour baseline at 24fps

Normal-speed storage:

1.5 hours × 500GB = 750GB

High-speed storage:

0.333 hours × 500GB × 2.5 = about 416GB

Base total: roughly 1.17TB. With a 20% production buffer, allocate about 1.4TB for that camera.

The 20 high-speed minutes create more than half the storage of the 90 normal-speed minutes. A schedule that lists only “110 minutes recorded” hides this difference.

High frame rate may change the sensor window

Cameras often reach higher frame rates by reading a smaller area of the sensor. A cropped window contains fewer pixels, which reduces the rate compared with scaling full-resolution capture alone.

For example, full-sensor 6K at 60fps and a 2.8K crop at 120fps cannot be compared using fps only. Calculate each with its actual pixel dimensions. The higher fps may be partly offset by the smaller frame.

Record the exact menu mode in the camera report:

• Sensor resolution or window
• Project frame rate
• Off-speed/sensor frame rate
• Compression setting
• Shutter behavior

That information lets post interpret motion correctly and lets production reconcile actual files with the storage plan.

Constant Quality becomes harder to predict at high speed

Q modes already vary with image complexity. High-speed sequences often contain the very qualities that are difficult to compress: motion, splashes, particles, hair, fabric, foliage, and short shutter angles that preserve fine detail.

Use the upper Q estimate for card speed and the shorter duration for the media plan. Test the actual action. A static high-frame-rate chart does not represent water, debris, sports, or practical effects.

Card time shrinks by the same ratio

If a card records 100 minutes at 24fps, a simple proportional estimate gives:

• 80 minutes at 30fps
• 48 minutes at 50fps
• 40 minutes at 60fps
• 20 minutes at 120fps

This assumes the same resolution and compression. A sensor crop changes the relationship.

For a high-speed unit, media changes may occur much faster than the main unit expects. Confirm that card runners, labels, and offload capacity can handle the shorter cycle.

Post-production impact

High-speed capture creates more source frames, even if the final slow-motion shot is short. That affects:

• Copy and checksum time
• Proxy generation
• Cache and conform time
• Noise reduction and optical flow processing
• VFX frame count
• Archive capacity

A 10-second real-world take at 120fps contains 1,200 frames. Conformed to 24fps, it becomes a 50-second clip. VFX billing and render planning may follow the delivered frame count, while acquisition storage followed the capture stream.

Plan high-speed blocks separately

Build the day’s estimate as a sum of modes:

1. List every resolution/fps/compression combination.
2. Estimate real recorded minutes for each combination.
3. Calculate storage for each block.
4. Add the blocks before applying camera count.
5. Apply a larger buffer to unpredictable action or repeated effects.
6. Confirm media speed against the highest single mode.
7. Confirm offload capacity against the total volume and card turnover.

Use the BRAW calculator once for each mode. A blended daily estimate can be convenient for purchasing storage, but only the per-mode plan reveals whether an individual card or SSD can sustain and hold the high-speed shot.

Sources and calculation notes

• Blackmagic Pocket Cinema Camera technical specifications: camera-specific formats and storage-rate reference tables.
• Blackmagic RAW overview: manufacturer information about the codec and encoding modes.
• BRAW Planner methodology: the estimation formulas, unit conventions and limitations used on this site.

Workflow suggestions in this guide are planning guidance, not a claim that a particular camera or drive has been tested by the author.