Braw Calculator

Professional Blackmagic RAW Storage & Bitrate Estimation Tool

A BRAW calculator is a specialized utility designed for cinematographers and video editors using Blackmagic Design cameras. The BRAW calculator estimates the amount of storage space required for filming in the Blackmagic RAW format. Because BRAW is a high-efficiency codec that balances the benefits of RAW processing with the manageable file sizes of traditional video formats, accurately predicting your storage needs is critical for production planning. Whether you are shooting a documentary or a feature film, using a BRAW calculator ensures you never run out of space on set.

Who should use this? Primarily camera assistants (DITs), directors of photography, and post-production supervisors. One common misconception is that BRAW file sizes are fixed; however, because BRAW offers different compression ratios and quality levels, the output from a BRAW calculator can vary significantly based on your settings. Another misconception is that “Constant Quality” (Q0, Q5) can be perfectly predicted. In reality, a BRAW calculator provides an estimate for these modes, as the actual bitrate fluctuates based on the visual complexity of the scene.

BRAW Calculator Formula and Mathematical Explanation

The math behind a BRAW calculator relies on the pixel count, frame rate, bit depth, and the specific compression ratio chosen. Unlike uncompressed RAW, BRAW performs a portion of the de-mosaicing in the camera, allowing for significant data reduction.

The basic logic used by our BRAW calculator follows this derivation:

• Total Pixels: Width × Height
• Uncompressed Rate: Pixels × Frame Rate × 1.5 (for 12-bit depth estimation)
• Compressed Bitrate: Uncompressed Rate / Compression Ratio
• Total File Size: Compressed Bitrate × Time (in seconds)

Variable	Meaning	Unit	Typical Range
Resolution	The total pixel dimensions of the frame	Pixels	1920×1080 to 12288×6480
Frame Rate	Frames recorded per second	FPS	23.98 – 120 FPS
Compression	The ratio of data reduction	Ratio	3:1 to 18:1 (or Q0-Q5)
Duration	Total length of the footage	Minutes	1 – 1000+ mins

Practical Examples (Real-World Use Cases)

Example 1: Independent Short Film

A filmmaker is shooting a short film in 6K at 24fps using an 8:1 compression ratio. They plan to record for approximately 90 minutes. By entering these values into the BRAW calculator, they find they need roughly 420 GB of storage. This allows them to purchase appropriate 512GB CFast 2.0 cards or an external SSD with confidence.

Example 2: High-Frame Rate Commercial

A commercial production requires 4K DCI footage at 60fps for slow-motion effects, using the high-quality 3:1 ratio. For only 30 minutes of “raw” recording time, the BRAW calculator indicates a requirement of nearly 450 GB. This highlights how high frame rates and low compression ratios drastically increase data demands, necessitating high-speed NVMe storage solutions.

How to Use This BRAW Calculator

1. Select Resolution: Choose from 12K, 8K, 6K, 4K, or HD options from the dropdown.
2. Enter Frame Rate: Type in your project frame rate (e.g., 24 or 60).
3. Choose Compression: Select between Constant Bitrate (predictable) or Constant Quality (variable).
4. Set Duration: Enter the expected minutes of total footage you plan to record.
5. Read Results: The BRAW calculator will instantly display the total GB required and the MB/s data rate.
6. Copy and Share: Use the “Copy Results” button to paste the data into your production brief or gear list.

Key Factors That Affect BRAW Calculator Results

• Resolution Scale: Jumping from 4K to 12K increases the data load by a factor of 9, significantly impacting the BRAW calculator totals.
• Frame Rate Multiplier: Recording at 60fps instead of 24fps more than doubles the storage required per minute of real-time footage.
• Compression Efficiency: Using 12:1 instead of 3:1 reduces file size by 75%, which is a primary lever used by DITs to manage space.
• Constant Quality (Q) Modes: These modes adjust bitrate based on detail. A shot of a blank wall will result in a smaller file than a shot of blowing leaves, making the BRAW calculator estimation a “safe average.”
• Bit Depth: BRAW is inherently 12-bit, providing massive dynamic range, but this also means it carries more data than 8-bit or 10-bit h.264 formats.
• Storage Overhead: Always add a 10-15% buffer to your BRAW calculator results to account for formatting and system files on your media.

Frequently Asked Questions (FAQ)

Is the BRAW calculator accurate for Q0 and Q5 modes?

The BRAW calculator provides an estimate for Constant Quality modes. Because Q-modes vary based on scene complexity, the actual size may be slightly higher or lower than the calculated estimate.

Does frame rate affect the MB/s data rate?

Yes, higher frame rates require more data per second. Our BRAW calculator accounts for this by multiplying the per-frame data by the FPS value.

Can I use this for the Blackmagic Pocket Cinema Camera 4K and 6K?

Absolutely. This BRAW calculator supports all resolutions used by the BMPCC 4K, 6K, 6K Pro, and the URSA Mini Pro series.

What is the difference between 3:1 and 12:1 in BRAW?

The ratio represents the level of compression. 3:1 is “near-lossless” with very high bitrates, while 12:1 is highly compressed, suitable for long-form interviews or web content where storage is limited.

Why does my 12K footage take up so much space?

12K resolution (80 megapixels per frame) is massive. Even with compression, the data throughput is immense, often exceeding 500 MB/s, as shown in the BRAW calculator.

Do I need a special SSD for BRAW?

The “Data Rate” result in our BRAW calculator tells you the minimum sustained write speed your drive needs. For high-res BRAW, you often need NVMe SSDs or high-end CFast 2.0 cards.

How does BRAW compare to ProRes?

BRAW is often more efficient than ProRes 4444 while offering RAW controls. You can use our BRAW calculator to compare sizes against known ProRes bitrates.

Is there a BRAW calculator for mobile?

This web-based BRAW calculator is fully responsive and works perfectly on iPhones, Android devices, and tablets for use on set.

Related Tools and Internal Resources

• Video Storage Calculator – A general tool for various codecs like H.264 and ProRes.
• Bitrate Calculator – Calculate specific bitrates for streaming and export.
• Codec Comparison Tool – Compare BRAW vs ProRes vs REDCODE.
• 4K Video File Size Calculator – Specifically for standard 4K UHD workflows.
• Frame Rate Converter – Change project timebases for slow motion.
• Camera Runtime Calculator – Estimate battery and storage life for production.