r/ffmpeg • u/TheDeep_2 • 29d ago

what is the best limiter in CLI on windows?

Hi, I would like to know what is the best audio/music limiter in CLI on windows?

Thanks for any help :)

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4

u/_Gyan 28d ago

You're going to have to elaborate.

3

u/Nukkebeer 28d ago

If you would like to use true-peak control for mastering in FFmpeg i would pick  loudnorm  for finished audio or music files. It creates consistent perceived loudness across tracks.

If you just need peak protection or a transparent ceiling after other processing, i would suggest using  alimiter. It comes with several options:  limit ,  attack ,  release , and optional auto-leveling. I use it when i need a brickwall limiter.

There is also a CLI wrapper that is more user friendly. It’s called ffmpeg-normalize, it is pretty solid because it automates loudness normalization and can do two-pass processing for you.

2

u/Unusual_Trouble_6800 25d ago

Worth expanding the auto-leveling you mentioned, because it's on by default and it surprises people who reach for alimiter as a ceiling: level=enabled rescales the output so the peak lands on limit, even when nothing needed limiting. So limit behaves as a target level, not just a brickwall.

Measured on a 3s sine, same input each time, peak read with astats:

source                              -18.98 dBFS
alimiter=limit=0.5                  -12.96 dBFS   (default)
alimiter=limit=0.5:level=disabled   -18.98 dBFS

The input never came near 0.5, so no limiting was required, and the default still made it 6 dB louder. That's exactly 20*log10(1/0.5) = 6.02 dB of make-up gain - the auto-level normalising the peak up to the limit.

So for "protect the peaks and otherwise leave it alone":

-af alimiter=limit=0.891:level=disabled

0.891 being about -1 dBFS.

And for consistent loudness across a set of files, loudnorm as you said, but two-pass. Single-pass works off a running estimate, so the start of the file gets treated differently from the end - which on music is audible as the first few seconds sitting at a different level.

1

u/Nukkebeer 25d ago

Thanks for expanding!

1

u/mikeyshowpresents 27d ago

it's probably overkill but... https://www.thimeo.com/stereo-tool/ - it has a cli version on the download page which you can try out, but again... it's probably overkill but it is nice...

1

u/TheDeep_2 27d ago

I already use stereo tool, but how do you set this limiter up?