FPV Log Analyzer

English · Русский

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A blackbox log analyzer for FPV drones: charts that help you find the cause of a problem — noise, filters, response, motors. Not an autotuner. Linux and Windows, a single executable.

Reads logs from Betaflight (3.x – 2026.x), INAV, EmuFlight and Rotorflight, including logs with non-standard fields. The interface is available in English and Russian: it follows the system language and can be switched from the top bar.

Run

Download a build for Linux or Windows from the releases page, or build from source:

cargo run --release -- path/to/log.bbl

You can also drop a log onto the window or use the "Open log…" button.

What it shows

Tab	Contents
Overview	Per-axis summary; findings (each links to its tab): whether a peak comes from motors or the frame, prop wash, phase margin, motor saturation; what to enable in the firmware for a better log
Curves	Signals per Roll / Pitch / Yaw. The time zoom selects the range for the rest of the analysis; two cursors measure an interval and its frequency
Spectrum	Noise before and after filters, filter cutoffs and delay, a two-stage trial filter (PT1–PT3, biquad)
Noise map	Noise vs throttle or motor RPM, with filter cutoffs and RPM harmonics overlaid
Spectrogram	Noise over time
Response	Step response, gain and phase, phase margin; split by stick rate or by throttle
Error	Tracking error and how it depends on stick rate
Motors	Load, saturation, vibration at each motor's rotation frequency
Settings	Parameters from the log; differences between two logs when comparing

"Compare with…" overlays up to three more logs on the spectrum and the response; "Save snapshot" writes a PNG next to the log. The language, the last folder and the chosen fields are remembered between runs.

Without a window

fpv-log-analyzer log.bbl report      # findings and events as text
fpv-log-analyzer log.bbl csv         # the record as CSV
fpv-log-analyzer log.bbl response    # spectra, delay, response and margins as a table
fpv-log-analyzer log.bbl step+save   # a PNG snapshot of a tab

Build and test

cargo build --release                                   # Linux
cargo build --release --target x86_64-pc-windows-gnu    # Windows
cargo test --release

License

GPL-3.0-or-later, see LICENSE. The interface font is IBM Plex Sans (SIL OFL 1.1).