[FFmpeg-devel] [PATCH 2/3] lavfi/ebur128: add metadata injection.

Nicolas George nicolas.george at normalesup.org
Thu Mar 14 16:33:20 CET 2013

Le quartidi 24 ventôse, an CCXXI, Clement Boesch a écrit :
> + at item volnorm
> +Set volume normalization metadata injection. Disabled by default. It accepts the following values:

IMHO, this is not a good design. There are other uses for ebur128 metadata
than volume normalization: injecting all variables, and let the parts that
use it choose is better.

> +
> + at table @option
> + at item M
> +Volume adjustment calculated according to the momentary loudness (400ms)

This one is completely useless for volume normalization: if there is a short
break in a conversation (after an embarrassing question=, it will make the
background music very loud during that break.

> + at item S
> +Volume adjustment calculated according to the short-term loudness (3 seconds)

If the 3 seconds are not centered on the current sample, they are not useful
for volume normalization.

And 3 seconds is probably too short; the time constant needs to be

> + at item I
> +Volume adjustment calculated according to the integrated loudness (from the beginning)
> + at end table

This one is completely useless for volume normalization, I already

Note that all these values are interesting by themselves. Jut not for volume
normalization. I am all in favour of injecting them as metadata.


  Nicolas George
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