[FFmpeg-user] Increasing audio

Cecil Westerhof Cecil at decebal.nl
Sun Apr 2 01:27:03 EEST 2017

On Saturday  1 Apr 2017 23:51 CEST, Moritz Barsnick wrote:

> On Sat, Apr 01, 2017 at 23:41:21 +0200, Cecil Westerhof wrote:
>>> You can use then use that value for the volume filter - note the
>>> "dB" syntax:
>>> $ ffmpeg -y -i speaker.MP4 -vcodec copy -af volume="7.7 dB"
>>> speakerAudioInc.MP4
>> Almost all give 0.0 dB (12), or -0.0 dB (4). When using that there
>> will change nothing. Or am I overlooking something?
>> There is also a -0.4 dB and a -0.2 dB.
> 0 dB change indeed means no change (it's a logarithmic scale - sorry
> if that's too mathematical for you). In other words, the loudest
> parts of the file are already at maximum, and raising their volume
> will introduce clipping, what could be perceived as distortion.

That sounds quit weird to me, because everything was very subdued in
my opinion.

> Apparently, even at "volume=3", it's not noticable to you yet, at
> "volume=4" it is.

At volume=3 I do not hear distortions. At volume=4 a lot. But maybe I
am just to tired: it was an enervating day after an enervating week.

> Did you try dynaudnorm? If "volume=3" isn't good enough for you, it
> could be a better solution.
> https://ffmpeg.org/ffmpeg-filters.html#dynaudnorm

I am already uploading one. (One person could not wait to see how she
performed.) I will look into your suggestion tomorrow.

Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof

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