从均衡器的音频数据 [英] Equalizer from audio data

问题描述

我有一个MP3文件，所以我需要发挥它，以及（在附加的图像等）显示均衡器。结果
所以打是不是问题，但我不知道如何来衡量基于频率当前播放的样本星展的力量。

I have a mp3 file, so I need to play it, and display an equalizer (like in attached image).
So playing is not problem, but I have no idea how to measure power of current playing sample's dBs based on frequency.

通过哪些步骤，我可以得到的数据为当前样品的展示分贝？结果
的当我想，我需要在不同频率的权力的某些阵列，对吗？的

By which steps I can get data for displaying dBs of current sample?
As I guess, I need to get some array of powers in different frequencies, am I right?

下面是什么，我想实现的例子：结果
https://www.youtube.com/watch?v=7oeb-OIOe-0 结果
https://www.youtube.com/watch?v=PwmUhTDr0Y0

Here is examples of what I want to achieve:
https://www.youtube.com/watch?v=7oeb-OIOe-0
https://www.youtube.com/watch?v=PwmUhTDr0Y0

推荐答案

从时域变换到频域的标准方法是一个的傅里叶变换。

The standard way to transform from time domain to frequency domain is a Fourier Transform.

苹果<一个href=\"https://developer.apple.com/library/ios/documentation/Performance/Conceptual/vDSP_Programming_Guide/UsingFourierTransforms/UsingFourierTransforms.html\"相对=nofollow>提供之一VDSP （矢量数字信号处理）。

Apple provide one in vDSP (vector Digital Signal Processing).

演练使用这个库这里。另一个例子（蝙蝠！）这里。

Walkthrough using this library here. Another example (for bats!) here.

顺便说一句，我不会把这个均衡器 - 对我来说，这将是东西，改变在不同频段的波形的相对组件

By the way, I wouldn't call this an equalizer - to me that would be something that alters the relative components of a waveform in different frequency bands.

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