# [FFmpeg-devel] [PATCH] lavfi: add volumedetect filter.

Nicolas George nicolas.george at normalesup.org
Sat Aug 18 18:33:04 CEST 2012

Le duodi 2 fructidor, an CCXX, Stefano Sabatini a écrit :
> min_volume may also be useful

Probably not: it is likely to be PCM=0 <=> -\infty dB, clamped to -91 dB.
Remember that this is a per-sample volume. A minimum on a sliding window may
be useful, but it is more complex, and this filter aims to be very fast.

> I suggest something along the line:
<snip>

Done.

> A comment mentioning that the values are normalized into unsigned
> values may help first-time readers.

Done in the above doxy.

> Could take a value and compute its square, rather than do this in the
> caller.

The value "power" is already squared when we need to convert it into dB.

> > +    return log(d) * -4.3429448190325182765112891891660508229;
> I'm lost here, what's this constant?

-10/log(10), added as a comment.

> relic?

Yes, removed.

> Please comment this block.

Done.

Regards,

--
Nicolas George
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