How Much Data Does a Documentary Actually Generate? A Real-World Breakdown by Shoot Day
The Director Who Showed Up With Two 4 TB Drives for a 30-Day Shoot
A documentary director starts a 30-day observational shoot with two 4 TB portable drives. He calculated storage based on a rough estimate of "a few hours per day." On day three, the DIT tells him that shooting at Sony FX9 all-intra 422 at 240 Mb/s for 8 hours per day produces approximately 216 GB per day. By day four, both drives are at 70% capacity. He orders two more drives overnight shipping. They arrive two days later. In between, the DIT is offloading footage onto the same cards being used to shoot, cycling them without a verified backup copy on a separate drive. On day six, a card develops a read error. Four hours of footage from that day -- no backup -- is partially recoverable by a data recovery service at a cost of $1,200 and a one-week turnaround.
The storage problem in documentary production is not that filmmakers don't know storage is important. It's that they estimate it without calculating it. This post gives the actual numbers by camera, codec, and shooting style, so the calculation is done before the first card is formatted.
Storage figures in this post draw from manufacturer published codec specifications and independent bitrate measurements from the Digital Cinema Society's 2024 codec benchmark reports.
Daily Data Generation by Camera and Codec
The base formula is:
Daily Data (GB) = Bitrate (Mb/s) ÷ 8 × 3600 seconds × Hours Shooting| Camera | Codec / Mode | Bitrate | Per Hour | Per 8-Hour Day |
|---|---|---|---|---|
| Sony FX9 | All-Intra 4K 422 | 240 Mb/s | 108 GB | 864 GB |
| Sony FX9 | Long-GOP 4K 422 | 100 Mb/s | 45 GB | 360 GB |
| Sony FX6 | 4K All-Intra | 240 Mb/s | 108 GB | 864 GB |
| BMPCC 4K | BRAW 5:1 | ~128 Mb/s avg | 57.6 GB | 461 GB |
| BMPCC 4K | BRAW 12:1 | ~43 Mb/s avg | 19.4 GB | 155 GB |
| BMPCC 6K | BRAW 5:1 | ~176 Mb/s avg | 79.2 GB | 634 GB |
| Canon C300 Mk III | Cinema RAW Light | 810 Mb/s | 365 GB | 2,916 GB |
| Canon C70 | C4K All-Intra XF-AVC | 810 Mb/s | 365 GB | 2,916 GB |
| DJI Air 3 (B-roll drone) | 4K H.265 | 150 Mb/s | 67.5 GB | 540 GB |
Important note: Documentary productions rarely shoot for a full uninterrupted 8 hours. Active camera time on a typical observational or interview documentary is 4-6 hours per shoot day after setup, repositioning, and non-camera time. Multiply the per-hour figure by your realistic active shooting hours for a more accurate daily estimate. Use the Codec Storage Calculator to input your specific camera, codec, and daily shooting hours for a precise figure.
The Backup Overhead Multiplier
Raw acquisition data is only part of the storage picture. A documentary data workflow requires:
- Raw acquisition: 1x
- Verified backup copy (on-set): 1x (total: 2x raw acquisition)
- Proxy files for editing: Approximately 10-15% of raw acquisition size for 1080p H.264 proxies
- Editor's working project files: 5-10 GB per editing day (typically minor)
- Final archive copy: 1x raw acquisition (offsite or cloud)
A conservative total multiplier is 2.1x raw acquisition for a production that maintains one verified backup and proxy files. A production that maintains two independent backups (best practice) uses 3.1x raw acquisition.
Example: A 30-day documentary shooting Sony FX9 all-intra at 5 hours per day:
- Per day raw: 108 GB × 5 = 540 GB
- Total raw (30 days): 16.2 TB
- With 2x backup: 32.4 TB
- With proxies: ~34 TB
This is more than eight 4 TB portable drives. The production that brought two drove into a serious problem on day three.
Documentary Shooting Styles and Their Data Profiles
Style 1: Observational / Fly-on-the-Wall (High Volume)
Running camera for extended periods with minimal stopping. Multiple cameras rolling simultaneously for key events. This style generates the highest daily data volumes because the shooting ratio can be 30:1 to 50:1. At a 40:1 ratio on a 90-minute finished film, the production is acquiring 60 hours of footage. At 540 GB per 5-hour day, that's 6,480 GB (6.5 TB) of raw acquisition -- requiring at least 13 TB of media with one backup copy.
Style 2: Structured Interview and B-Roll (Moderate Volume)
Separate interview setups with scripted B-roll capture. Shooting ratios of 8:1 to 15:1. Cameras rolling for 4-5 hours per day. More controlled than observational but still generates significant daily volumes on higher-bitrate cameras. The storage estimate variables post covers the variables that cause storage estimates to diverge from actuals on this type of production.
Style 3: Travel Documentary, Weight-Constrained
One DP, one camera, small kit. The weight constraint often means fewer drives and smaller media. BRAW 12:1 compression (approximately 155 GB per 8-hour day) reduces data pressure significantly versus all-intra codecs, while retaining raw parameter control for the colorist. The building a data management workflow for a small crew post covers how to structure the backup process when the only person available to do it is also operating the camera.
Pro Tips
Tip 1: Calculate storage requirements before pre-production ends, not during production. The Codec Storage Calculator takes camera model, codec, daily shooting hours, and production length and returns total raw acquisition, backup requirements, and proxy overhead in a single output. This calculation should be in the production budget as a line item with specific drive counts and costs.
Tip 2: For documentaries using Sony FX cameras, the all-intra vs. long-GOP choice is a storage-versus-workflow decision. All-intra (240 Mb/s) produces files that edit more smoothly without proxies but generate 2.4x more data than long-GOP (100 Mb/s) on the same shoot. For a 30-day production at 5 hours per day, the difference is 15.5 TB of additional storage cost -- approximately $600-$1,200 in drives -- versus the cost of slower proxy rendering. Calculate both paths before choosing.
Tip 3: Always verify backup integrity, not just backup completion. A file copy that completes without error confirmation is not a verified backup. Use a checksumming tool (YoYotta, SilverStack, or DIT|CRM) that generates an MD5 or SHA-256 checksum for each file during the original ingest and verifies the backup against that checksum. An unverified backup is a false sense of security.
Frequently Asked Questions
What is the most storage-efficient documentary codec that doesn't sacrifice post-production quality?
BRAW 12:1 on Blackmagic cameras is the best balance of storage efficiency and post-production latitude. At approximately 155 GB per 8-hour shooting day versus 864 GB for Sony all-intra 4K, the storage saving is substantial. BRAW retains full raw parameter control in DaVinci Resolve for ISO, white balance, and exposure adjustments, unlike H.264/H.265 which bakes in camera-processed decisions. For productions that aren't using Blackmagic cameras, Sony's Long-GOP 100 Mb/s mode is the practical efficiency option, though it doesn't offer raw parameter control.
How many GB per minute does 4K H.264 generate?
Standard 4K H.264 at typical documentary camera settings (approximately 100 Mb/s) generates about 0.75 GB per minute. A 5-hour shoot generates approximately 225 GB. The exact figure varies with bitrate setting, scene complexity (high-frequency scenes compress less efficiently and may temporarily exceed the stated bitrate), and whether the camera uses variable or constant bitrate encoding.
Should I use LTO tape for documentary archival?
LTO-9 tape (18-45 TB per cartridge at $50-$100 per cartridge) is the professional standard for long-term archival of completed productions. For productions actively shooting, LTO requires a dedicated tape drive ($3,000-$8,000) and is not practical for on-set backup. For final project archival after delivery, LTO is significantly cheaper per terabyte than hard drives over a 5-10 year period. Many post facilities and archives use LTO for finished project vaulting.
Does a documentary need a full DIT or can the director handle data management?
The data management function needs to be performed by someone with undivided attention during the backup window. A solo director/camera operator who is also offloading cards, driving to the next location, and setting up the next interview is a high-risk data management configuration. The minimum viable setup for multi-day documentary production is a dedicated data management workflow -- even if it's a dedicated device (Nextorage NPS-10, Atomos Sumo 19) rather than a dedicated person. The backup strategy calculator models the minimum hardware required for different shooting configurations.
Related Tools
The Codec Storage Calculator generates a precise daily and total storage estimate for any camera, codec, and shooting duration. The Backup Strategy Calculator models the hardware and drive count required to maintain the recommended 3-2-1 backup standard. The Data Rate Calculator converts between bitrate, resolution, and frame rate to verify manufacturer-published figures against your specific recording settings.
Conclusion
Documentary storage is calculated, not estimated. The difference between a director who arrives on set with the right number of drives and one who runs out on day three is a 10-minute calculation done in pre-production. The numbers in this post give you the starting point. Multiply by your realistic daily shooting hours, add the backup overhead multiplier, and the total figure is the storage budget before a single card is formatted. What documentary shoot generated the most data per day you've experienced, and what backup protocol were you running?
