Audio Automatic Fade Designer

A fade designer that reasons in music units instead of raw seconds. The tempo engine converts your BPM to bar length (4 beats = 240/BPM seconds) and offers fade-ins from half a bar to 4 bars and fade-outs from 1 to 8 bars; the silence engine auto-derives lengths from the detected music span (fade-in capped at a third of the music, fade-out at 60%, bar-based defaults) for tracks where you just want it to fit. Both engines first run FFmpeg silencedetect (−50 dB, 0.25 s minimum) to find where the music actually starts and ends, so a fade-out is never wasted fading into trailing silence — it ends exactly where the music ends — and the leading fade begins at the first sound. Detected silence can optionally be trimmed from the render (atrim + asetpts). Fades render through afade with a logarithmic curve by default: a straight line in decibels reads as perceptually linear to the ear, while the default triangular curve audibly drags near the end — linear is only right for phase-matched crossfades, and quarter-sine / logistic-sigmoid shapes are offered for DJ and cinematic tastes. The report lists the detected silence intervals, the chosen bar math (BPM → seconds), where each fade starts and ends, and the final duration.