iOS - Audio level metering of app's audio output

Question

I want to show audio meter levels in my app from the audio that my app send to the speaker. I can find the audio level from AVAudioPlayer but it works on audio files.

I have tried to acheive this using as it is provided in its documentation here but I am unable to find out how to do that. 来实现此目的，如此处的文档中所提供的那样，但是我无法找到如何做到这一点。

Is it possible to achieve this in ios? Can anyone suggest me any library, audio engine or method?

Thanks in advance

Answer 1

If you are using "remote i/o audio unit for handling audio input and output" this is a possibility:

https://developer.apple.com/library/ios/samplecode/aurioTouch2/Listings/ReadMe_txt.html

"… , and a sonogram view (a view displaying the frequency content of a signal over time, with the color signaling relative power, the y axis being frequency and the x as time). Tap the sonogram button to switch to a sonogram view, tap anywhere on the screen to return to the oscilloscope. Tap the FFT button to perform and display the input data after an FFT transform. Pinch in the oscilloscope view to expand and contract the scale for the x axis." …