Demo: https://youtu.be/lo-eb6zSxgQ

A simple rough proof-of-concept starter script to stabilize video stream with low latency from wifibroadcast FPV (or any streaming source). Works out of the box sufficiently well with 720p and lower digital FPV video streams. This is not meant to be a cinema quality stabilizer: It is tool to make a jittery/bumpy FPV feed tolerable while adding the least possible amount of latency to the stream.

About: I put this together because I could not find any simple open-source ultra low latency software stabilization for FPV. Most video stabilization solutions are designed for post-processing video files, and the fastest live-streaming stabilizers that I could find added hundreds of milliseconds latency at best which is not suitable for FPV. I observed that the common solution to reduce processing time is to downsample the frames, run the point-feature matching (or other processing) on the low-res frames, then scale up the translation to the full frame size by multiplying the resulting matrix against a scale matrix. Unless I was doing it wrong (a definite possibility), using the downsample method unsurprisingly affects the stabilizer's accuracy, resulting in a noticeable annoying jitter when operating an off-road vehicle at high speeds. The simple method employed here differs in that it crops out a region of interest (ROI) then moves each point found within the ROI to the full-sized frame's coordinate before further processing and smoothing. It does not downsample the entire frame and therefore retains the same stabilization accuracy as a full sized frameset, resulting in a smooth low-latency stabilized video stream. I am certain I am not to first to do this but I could not find any open-source examples as everyone appears to employ the downsample method, if any.

Intended audience: Folks using wifibroadcast FPV variants with a x86 groundstation. Doubtful this will work at all on Raspberry Pi groundstations (haven't bothered to try).

Requires: Python, OpenCV-python, gstreamer and probably other libraries I forgot about

Linux (roughly) - apt install python3 python3-opencv gstreamer1.0-plugins-*

Windows - Install python from the windows app store then open a command prompt and run 'pip install opencv-python'

Included in this repo is a test shaky video. To test run:

python ejo_wfb_stabilizer.py UnstabilizedTest10sec.mp4

...or edit the file and set the SRC variable to your own streaming source.

Notes:

Higher FPS = lower latency, better cleaner stabilization.

On a moderate PC, this should stabilize 720p @ 49fps (v1 camera max 720p fps) pretty well, however, for ultra fast movements it is better to run 60-90fps which requires a genuine V2 cam or V1 cam in VGA mode. I often run the V1 camera VGA mode @ 90fps at 960x540 which stabilizes really well and feels like a brushless gimbal, the trade-off being lower resolution. Should be good for RC FPV car racing.

My groundstation PC has a nvidia gpu and opencv compiled with cuda support and can handle the stabilization demands at 720p. A lower-end PC may require running a lower resolution stream, lower fps, or adjusting the script to use a smaller ROI.