How It Works
Our BRAW calculator uses official Blackmagic Design specifications to provide accurate storage and data rate estimates for your Blackmagic RAW footage. Here's how the calculation process works.
The Calculation Process
1. Resolution Impact
Resolution is the primary factor determining file size. Each resolution contains a specific number of pixels per frame:
- 12K (12288x6480): ~79.6 million pixels per frame
- 8K (8192x4320): ~35.4 million pixels per frame
- 6K (6144x3456): ~21.2 million pixels per frame
- 4K (4096x2160): ~8.8 million pixels per frame
- 2.8K (2868x1512): ~4.3 million pixels per frame
2. Frame Rate Scaling
Frame rate directly multiplies the data requirements. Our calculator uses 24fps as the baseline and scales proportionally:
Formula: Adjusted Data Rate = Base Data Rate × (Your Frame Rate ÷ 24)
Example: If 6K BRAW 8:1 at 24fps = 113 MB/s, then at 60fps = 113 × (60÷24) = 282.5 MB/s
3. Compression Types
Constant Bitrate (3:1, 5:1, 8:1, 12:1)
These settings maintain a fixed compression ratio regardless of image complexity. The number represents how much the original RAW data is compressed:
- 3:1: Highest quality, compresses original data by 3x
- 5:1: Excellent balance of quality and file size
- 8:1: Good quality with efficient storage use
- 12:1: Most compressed, smallest files while maintaining good quality
Constant Quality (Q0, Q1, Q3, Q5)
These settings vary the compression based on image complexity to maintain consistent visual quality:
- Q0: Maximum quality, variable bitrate (typically higher than 3:1)
- Q1: Very high quality with some compression efficiency
- Q3: High quality with good compression efficiency
- Q5: Efficient compression while maintaining excellent quality
Practical Example
Scenario: 1-hour interview in 6K BRAW 8:1 at 24fps
Base data rate for 6K BRAW 8:1: 113 MB/s
Frame rate adjustment: 113 × (24÷24) = 113 MB/s (no change)
Duration: 1 hour = 3,600 seconds
Total storage: 113 MB/s × 3,600s ÷ 1,024 = 397 GB
Data Rate vs. Storage Requirements
Understanding both metrics helps with different aspects of production planning:
Data Rate (MB/s)
Determines the minimum sustained read/write speed your storage device needs for smooth recording and playback.
Total Storage (GB)
Helps you plan memory card capacity, backup drive sizes, and overall storage infrastructure needs.
Accuracy and Limitations
Our calculations are based on official Blackmagic Design specifications and provide highly accurate estimates. However, actual file sizes may vary slightly due to:
- Image complexity variations (especially with Constant Quality modes)
- Camera firmware differences
- Recording conditions and settings
- File system overhead
Best Practice: Always plan for 10-15% more storage than calculated to account for these variations and provide a safety buffer for your productions.