Pipeline FPS Drops at 4K/8K and Max FPS Error on OAK-4s Camera

AkshayKumar

Hi everyone,

I've implemented a simple pipeline for my OAK-4S (DepthAI 3) camera to handle 4K and 8K resolutions, but I'm facing consistent FPS issues and an error.

The issues I am facing are

4K Resolution - Unstable FPS:
- The FPS constantly fluctuates between ~30.10 and ~15.06 (e.g., 30.10, 15.06, 30.10, 15.02...). This drop is very regular and repeatable.
8K Resolution - Low and Unstable FPS:
- The FPS is very low and also unstable, fluctuating between ~3.61 and ~4.0.
8K Resolution - Max FPS Error:
- When I try to force 30 FPS at 8K, I get the following error:
  RuntimeError: Requested fps is higher than the sensor max fps with the selected resolution, requested: 30, max: 18.9 (startPipeline)

My questions are:

Root Cause: What is the root cause of these FPS drops, especially the consistent halving from 30 to 15 FPS at 4K?
8K Limitation: Why is the maximum achievable FPS for 8K only 18.9, and why is my actual FPS so much lower (3.6-4.0)?
Solutions: Are there any solutions or best practices to stabilize the FPS and achieve the best possible performance at these high resolutions?

I would greatly appreciate any insights or suggestions. Thank you!

OskarSonc

Hey @AkshayKumar
That behavior is expected — 8K NV12 frames are extremely large (around 50 MB each), so even at 4 FPS that’s roughly 200 MB/s of data, which already saturates a 1 GbE PoE link. That’s why the framerate drops and becomes unstable. The “requested 30, max 18.9” message simply means the sensor can’t physically run faster than 19 FPS at 8K.

The 4K oscillation between 30 and 15 FPS comes from back-pressure — the host can’t read frames quickly enough, so some get delayed or dropped.

To test your bandwidth, you can run our bandwidth test:
luxonis/oak-examplestree/master/random-scripts#oak-bandwidth-test

Also, we have an example for outputting max video:
https://docs.luxonis.com/software-v3/depthai/examples/camera/camera_max_resolution/

To get smoother performance, convert or compress frames on-device (e.g. H.265/H.264) or downscale before sending them to the host. Sending raw 8K NV12 over PoE will always be bandwidth-limited. Here is documentaion for that:
https://docs.luxonis.com/software-v3/depthai/depthai-components/nodes/video_encoder/

Hope this helps,
Oskar