O4 is DJI's fourth-generation digital video transmission system (the latest version of what DJI calls OcuSync). It's the radio link that carries live video down from the drone and control signals up from your controller or goggles. On camera drones like the Mini 4 Pro and Air 3S it delivers 1080p/60 live view and up to 20 km of range (FCC, in open, interference-free conditions). An upgraded O4+ on the Mini 5 Pro and Mavic 4 Pro extends that to 20 and 30 km. On FPV gear like the Avata 2 and the O4 Air Unit, it's tuned for low latency, down to about 15 to 24 ms.
O4 specs by product
| Product | System | Live view | Latency (DJI) | Max range (FCC) |
|---|---|---|---|---|
| Mini 4 Pro | O4 | Up to 1080p/60 | ~120 ms | 20 km |
| Air 3S | O4 | 1080p/30 or 60 | ~120 ms | 20 km |
| Mini 5 Pro | O4+ | 1080p/30 or 60 | ~120 ms | 20 km |
| Mavic 4 Pro | O4+ | 1080p/30 or 60 | ~130 ms | 30 km |
| Flip | O4 | Up to 1080p/60 | ~120 ms | 13 km |
| Avata 2 with Goggles 3 | O4 | 1080p up to 100 fps | 24 ms at 1080p/100 | 13 km |
| O4 Air Unit Pro | O4 | 1080p up to 100 fps | As low as 15 ms | 15 km |
| O4 Air Unit | O4 | 1080p up to 100 fps | As low as 20 ms | 10 km |
Latency on camera drones is measured drone to controller screen and depends on your phone; FPV figures are DJI's minimum with Goggles 3 in racing mode.
Frequencies
O4 hops between bands to dodge interference:
- 2.4 GHz (2.400 to 2.4835 GHz): longer reach, more crowded.
- 5.8 GHz (5.725 to 5.850 GHz): less crowded, shorter reach through obstacles.
- 5.1 GHz (5.170 to 5.250 GHz): available on many O4 products where local rules allow.
The O4 Air Unit uses only 5.1 and 5.8 GHz. Allowed bands vary by country, which is why DJI lists different range numbers for FCC (US), CE (Europe) and SRRC (China).
Is O4 encrypted?
Yes. DJI's security white paper says its OcuSync link is encrypted with AES-256, with a new session key each time the device powers on. See is DJI safe.
Real-world range
Those 20 to 30 km numbers are lab-style maximums. Buildings, trees, terrain, Wi-Fi and cell towers cut range sharply, and in the US you must keep the drone within visual line of sight anyway. To get the most from O4:
- Angle the controller antennas so they face the drone, as shown in your manual's "optimal transmission zone."
- Keep a clear line between you and the drone; don't fly behind hills or buildings.
- Fly away from strong Wi-Fi and radio sources.
See drone keeps losing signal and how far can a drone fly.
O4 for FPV builders
The O4 Air Unit brings DJI's digital link to custom FPV quads. It weighs about 8.2 g with its camera, records 4K/60 on board, and works with DJI Goggles 3 and Goggles N3. The larger O4 Air Unit Pro adds a 1/1.3-inch sensor, 4K/120 recording and 15 km range. See FPV terms explained and build an FPV drone.
DJI's other video links
DJI also makes a standalone SDR Transmission system for cinema cameras on the ground; it's a separate product line from O4. Enterprise drones use O4 Enterprise, with extra options like relays.
Shopping by range? Compare models in our drone finder.
Related guides
- How DJI drones transmit live video (O4 and OcuSync)
- DJI O4 Air Unit: setup, range and compatible goggles
- FPV drone speed, range and latency explained
- How far can the DJI Avata 2 fly? Range and transmission explained
- How far can the DJI Mavic 4 Pro fly? Range and transmission explained
- How far can the DJI Mini 4 Pro fly? Range and transmission explained
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