# Violin Coach — https://vioanalyze.berkay.tools Honest practice feedback for solo violin. Upload a recording (audio or video); a WebAssembly DSP engine (pYIN pitch tracking) analyzes it entirely client-side and produces a structured report on tuning, intonation, rhythm and tone. There is deliberately NO server API — the recording never leaves the device. To use this site as an agent you must drive a real browser (headless Chrome works; the page is verified to run end-to-end under browser automation). ## Driving the page 1. Load the page and let it settle (the ~1.2 MB WASM engine boots in a worker). 2. Set the recording on the hidden file input `#file-input` (e.g. Playwright's setInputFiles — no drag-and-drop needed). Supported extensions: .mov .mp4 .m4a .wav .mp3 .aac .flac .ogg .aif .aiff .mkv .webm .avi Optional: set `#a4-input` first (concert reference in Hz, 400–480, default 440) if the player tunes to e.g. 442. 3. Wait until `window.violinCoach.status` is "done" or "error". DOM equivalents: `` gains class `done`; on failure `#error-box` unhides. Budget roughly 15 s of analysis per 90 s of audio. 4. Read the result — no download clicks required: - `window.violinCoach.analysis` parsed analysis.json (schema below) - `window.violinCoach.summaryMd` Markdown summary - `window.violinCoach.reportHtml` self-contained HTML report - `window.violinCoach.headline` { severity, title, detail } — top finding - `window.violinCoach.error` message string when status is "error" The raw JSON is also mirrored into the DOM after each run: `