CODEWITHSUNDEEP
iosobjective-cxcode
user247
user247

Reputation: 416

get the sound level in decibels using objective-c

I am new to iOS world . I have a doubt . I would like to achieve the dB SPL meter .I have two buttons 1. play song 2. display decibel value . When I click on the Play song button it is playing the song. My question is while playing the sound I have to display the sound value in decibels which comes from iPhone . I have searched in the google . But I am not getting any basic ideas to start this app . Please give me idea to do this . Let me know if my question not clear .

Upvotes: 2

Views: 3421

Answers (2)

Dennis Nedry
Dennis Nedry

Reputation: 4747

A possible solution to your problem could be to convert it from a logarithmic to a linear scale:

CGFloar linearScale = powf(10.f, logarithmicScale) * 20.f;

where logarithmicScale is the value you get from AVFoundation. The linear scale should be much easier to visualize!

Upvotes: 0

Thomas Zoechling
Thomas Zoechling

Reputation: 34253

You didn't specify which framework you are using for playback. But assuming you are using AVFoundation, you could use AVCaptureAudioChannel averagePowerLevel or peakHoldLevel.

The relevant property for your problem seems to be averagePowerLevel, which is (from the docs):

The instantaneous average power level, in dB. (read-only)

For details, see Apple's AVFoundation Programming Guide, which includes a section about audio previews.

Upvotes: 3

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