ALEXA LF: ARRIRAW bitrate & storage per hour
The ARRI ALEXA LF records ARRIRAW. Maximum sustained write speed: 2000 MB/s. Figures per sensor mode and compression level at 24 fps — video only.
Figures at 24 fps. Other frame rates scale linearly — open the calculator to change them.
Open Gate 4.5K (4448×3096, max 90 fps)
| Compression | Ratio | Bitrate | Data rate | Storage / hour |
|---|---|---|---|---|
| Uncompressed | 1:1 | 3,960.0 Mbps | 495.00 MB/s | 1,782.0 GB |
| HDE | 1.67:1 | 2,376.0 Mbps | 297.00 MB/s | 1,069.2 GB |
Content-dependent codecs (constant quality, VBR) vary their data rate with scene complexity — the figures above are typical values, and actual rates range around them.
Cards and recording time
The ALEXA LF sustains up to 2000 MB/s, so its media has to keep up with the mode you shoot. At the highest rate in the tables above (495 MB/s) the recording times per card are:
| Capacity | Recording time | Cards for 1 hour |
|---|---|---|
| 128 GB | 4 min | 14 |
| 256 GB | 9 min | 7 |
| 512 GB | 17 min | 4 |
| 1 TB | 34 min | 2 |
| 2 TB | 1 h 7 min | 1 |
Offloading a shooting day
90 minutes of takes come to about 2.7 TB. Over USB 3.2 Gen 2 (10 Gbps) that is 52 min for a single copy — double it if you verify with checksums, and multiply by the number of backups.
What hardware it needs
Playing this back in real time means sustaining 495.00 MB/s of reads. One hour of footage is 1.8 TB, and that is what has to travel every time you copy, back up or archive it.
Any card or drive rated below 495 MB/s sustained will drop frames on playback, whatever its peak speed says on the box.
| Interface | Sustained speed | Copying 1 hour |
|---|---|---|
| 1 GbE network (1 Gbps) | 110 MB/s | 4 h 30 min |
| USB 3.2 Gen 1 (5 Gbps) | 400 MB/s | 1 h 14 min |
| USB 3.2 Gen 2 (10 Gbps) | 850 MB/s | 35 min |
| Thunderbolt 3 / 4 (40 Gbps) | 2500 MB/s | 12 min |
Times are for a single copy without checksum verification. Verified offload reads back what it wrote, so it takes roughly twice as long.
Related guides
- Other ARRI cameras: ALEXA 65 · ALEXA 35 · ALEXA Mini LF · ALEXA Mini
Figures use decimal units (1 GB = 1000 MB), the convention used by drive and camera manufacturers. Computed with the same calculation engine as the Workflow Data Calculator — open it to add audio, streams, backup copies, offload time and storage cost, or to export a PDF report.
Certified Adobe & Blackmagic training and postproduction workflow consulting by Jorge Mochón — jmochon.training