问题描述
我正在尝试使用Qt(c ++)创建一个程序，当我使用 QAudiooutput播放音频文件(.wav，.mp3)时，该程序可以绘制幅度信号(如大胆但有动态波形的图)和 QIODevice .
I'm trying to create a program, using Qt (c++), which can plot the amplitude Signal (plot like audacity but dynamic waveform) when I playback an audio file (.wav, .mp3) using QAudiooutput and QIODevice.
我所做的:
使用 QAudioouput ，我可以播放任何音频文件，使用qwtplot可以绘制2D信号，在这种情况下，x轴就是时间y轴为振幅.
What I've done:
with QAudioouput I can play the any audio file, with qwtplot I can plot any signal in 2D, in this case, x-axis will be time and y-axis will be the amplitude.
现在，我的问题是如何获取每秒(时间)的幅度?
Now, my problem is how to get the amplitude for each second (time)?
任何帮助将不胜感激.
推荐答案
正常的，未压缩的音频表示形式只是其幅度随时间的变化. .wav 文件通常是未压缩的，因此单声道 .WAV 文件实际上是最简单的音频文件:只是一个标头，后面是一系列振幅.
The normal, uncompressed representation of audio is just its amplitude as a function of time. .wav files are ordinarily uncompressed, so a mono .WAV file is really the simplest of audio files: just a header followed by a series of amplitudes.
请注意，数字音频具有采样率.例如.32 kHz的采样率意味着您的WAV文件每秒具有32000个幅度.如果只有一个，您听不到！(＜20Hz).您可以在Audacity中看到这一点；您可以将波形放大很多.
Note that digital audio has a sampling rate. E.g. a 32 kHz sample rate means that your WAV file has 32000 amplitudes per second. If it only had one, you couldn't hear it ! (<20 Hz). You can see this in Audacity; you can zoom in quite a bit on the waveform.
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