TL;DR
We normalize audio to a consistent perceived loudness using FFmpeg's loudnorm filter in two passes: pass 1 measures, pass 2 applies a linear gain to the target. We'll parse the JSON, script it, batch it with ffmpeg-normalize, and verify with ebur128. Single-pass loudnorm pumps; don't use it for VOD.
If your library has one clip that whispers and the next one that blasts, your viewers are riding the volume knob. Peak normalization won't fix it (same peak, different perceived loudness). What you want is EBU R128 loudness normalization, and FFmpeg ships the filter to do it. Let's wire it up properly.
1. Why not single-pass?
The tempting one-liner is single-pass:
