dot-rms_filter: ffmpeg filter chain for a per-window RMS readout

In compost: Video Compositing via 'FFmpeg'

ffmpeg filter chain for a per-window RMS readout

Description

Slices the audio into window-sample blocks and prints each block's overall RMS level (dB) as ametadata. No file= option: the print stream goes to ffmpeg's stderr, which the caller captures and parses. Writing to a file= path breaks on Windows, where a drive-letter path (C:\...) is truncated at the colon by ffmpeg's filter-option parser and the metadata lands in a stray file named after the drive; reading stderr sidesteps path escaping entirely and behaves identically on every platform.

Usage

.rms_filter(window)

Arguments

window

Window size in samples.

Value

A single ffmpeg filter-chain string.

compost documentation built on Aug. 4, 2026, 5:11 p.m.