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tigrezno

Member

Registered: 2004-05-10

Posts: 64

Adding system wide audio filters?

I want to add a normalization filter to alsa, so any application sound is normalized (web videos, mplayer, and so on)

Is it possible?

Last edited by tigrezno (2011-02-03 15:06:32)

ngoonee

Forum Fellow

From: Between Thailand and Singapore

Registered: 2009-03-17

Posts: 7,356

Re: Adding system wide audio filters?

Theoretically impossible I think. 'Normalization' doesn't work unless you know before hand the loudest volume of each source. SOME music files have normalization data embedded inside. I'm pretty sure alert sounds don't.

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tigrezno

Member

Registered: 2004-05-10

Posts: 64

Re: Adding system wide audio filters?

So, normalization of streaming audio can't be achieved? (without some sort of metadata)

Themaister

Member

From: Trondheim, Norway

Registered: 2008-07-21

Posts: 652

Website

Re: Adding system wide audio filters?

You can gain something similiar using compressors and limiters, although this alters the audio. I think LADSPA can use compressors on audio streams.

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@ GitHub

ngoonee

Forum Fellow

From: Between Thailand and Singapore

Registered: 2009-03-17

Posts: 7,356

Re: Adding system wide audio filters?

So, normalization of streaming audio can't be achieved? (without some sort of metadata)

Not on-the-fly. I suppose you could always analyze the file before playing it. I'm pretty sure someone out there would have written (for example) an mpd plugin which runs over a file first, analyzing its peaks (or preferably the mean-square volume or something) and then applied per-file normalization.

It would mean quite a bit of processing for every single song though. Hence better to have metadata. Alternatively you could generate such metadata for every song on your playlist prior to that.

OR like the rest of us you could just bind some easily accessible keyboard shortcut to volup/voldown

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Allan-Volunteer on the (topic being discussed) mailn lists. You never get the people who matters attention on the forums.
jasonwryan-Installing Arch is a measure of your literacy. Maintaining Arch is a measure of your diligence. Contributing to Arch is a measure of your competence.
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brebs

Member

Registered: 2007-04-03

Posts: 3,742

Re: Adding system wide audio filters?

Already done (using "fastLookaheadLimiter", which is good enough) - see thread. Great for watching movies

ngoonee

Forum Fellow

From: Between Thailand and Singapore

Registered: 2009-03-17

Posts: 7,356

Re: Adding system wide audio filters?

Already done (using "fastLookaheadLimiter", which is good enough) - see thread. Great for watching movies

that's great, just knew someone would have something of this sort.

I'll stick to my volume keys though.

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Allan-Volunteer on the (topic being discussed) mailn lists. You never get the people who matters attention on the forums.
jasonwryan-Installing Arch is a measure of your literacy. Maintaining Arch is a measure of your diligence. Contributing to Arch is a measure of your competence.
Griemak-Bleeding edge, not bleeding flat. Edge denotes falls will occur from time to time. Bring your own parachute.