Normalize audio volume

Peak. The tool scans every sample to find the single loudest one, then scales the whole file by one fixed gain so that peak lands exactly on your target. It is not LUFS or ReplayGain, so two files normalised to the same target can still feel different in loudness. Nothing is compressed or limited, and the dynamics are untouched.

It is the target peak level in dBFS, where 0 is full scale, and it defaults to -1 to leave a little headroom. It must be a number of zero or less; a positive value is refused. Because the gain is computed as target divided by the measured peak, the loudest sample lands exactly on your target and nothing clips past it.

Because a single gain figure cannot be known until the loudest point in the whole file has been found. The first pass decodes every sample and tracks the peak. The second pass re-encodes, multiplying each sample by the gain. That means the audio is decoded twice, which is why long files take a while.

Always an MP4, named after your input with -normalized.mp4 on the end. A video track in the source is carried through unchanged, so normalising a video gives you the same picture with louder sound. The result text reports the measured peak in dBFS, the gain factor applied and the target you asked for.

Nothing is written. If the measured peak is zero the tool reports "audio is silent (peak is 0)" and stops, because scaling silence by any factor is still silence. You get the message and no output file rather than a pointless copy.

Because both the scan and the re-encode go through WebCodecs, which Node has no equivalent of. The CLI and MCP surfaces refuse it with "audio-normalize needs a browser (OffscreenCanvas). Use it at /video/audio-normalize instead." The file stays on your device in either case.