Sound level meter

bojkar 101 Mar 25, 2008 at 13:09

Hello I want do some kind of sound level meter (“equalizer” something like that) :
This equalizer is used to render level of recording sound I won do this with mixer api but I don’t know how. I know how to get volume, mute itp but don’t know this. I’d searched a lot of search engines and forums and nothing found :/ Please help.

P.S. Sorry for my english

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roel 101 Mar 26, 2008 at 08:56

I don’t believe you can do this with a mixer, the mixer just controls the various sound channels (microphone, line-in, midi, etc). You just need to sample the incoming sound, and take for some interval the maximum value, or the RMS, etc. If you want a real equalizer (with bars per frequency range), FFT is what you might need. Btw, that screenshot is from Audacity, it uses the PortAudio library to capture sound (what you need), and it is open source.

bojkar 101 Mar 26, 2008 at 12:28

I know that mixer api can do this. I try to use mixerGetLineControl & MIXERCONTROL_CONTROLTYPE_PEAKMETER but function return error :/ #1025 and I don’t know what to do :/ Please help