本文分享如何在 matlab 里面读取 wav 文件，播放 wav 文件，以及如何录制语音文件，保存语音文件。
代码中演示了如何改变音频文件的采样率（影响到播放速度），音量（影响到听到的声音大小）。
以及录制的数据如何保存到文件中。 如果使用其他的编程语言，也能通过相关的函数类库达到类似的效果，比如 Python :Playing and Recording Sound in Python – Real Python
Matlab 2021 中读取 wav 文件文件来自： http://mirlab.org/jang/books/audiosignalprocessing/example/sunday.wav
[y, fs] = audioread('sunday.wav');sound(y, fs);% Playback of the sound data (播放此音讯)time=(1:length(y))/fs;% Time vector on x-axis (时间轴的向量)plot(time, y);% Plot the waveform w.r.t、time (画出时间轴上的波形)
画出的图形如下：
打印出音频文件的参数信息：
myAudioRead 库函数来自： http://mirlab.org/jang/books/audiosignalprocessing/example.rar
fileName = 'welcome.wav';au = myAudioRead(fileName);y=au.signal; fs=au.fs; nbits=au.nbits;fprintf('Information of the sound file "%s":n', fileName);fprintf('Duration = %g secondsn', length(y)/fs);fprintf('Sampling rate = %g samples/secondn', fs);fprintf('Bit resolution = %g bits/samplen', nbits);
打印出来音频的总时长，采样率，采样位深（采样位分辨率）后，就可以进一步进行分析。
Matlab 中播放音频文件，播放3倍，15倍音量大小（震幅）的音频au = myAudioRead('welcome.wav');y=au.signal; fs=au.fs; nbits=au.nbits;% 播放音频：Playback with original amplitude (播放 1 倍震幅的音訊)audioPlay(au);% Playback with 3 times the original amplitude (播放 3 倍震幅的音訊)au.signal = 3*y;audioPlay(au); au.signal = 15*y;audioPlay(au);% Playback with 15 times the original amplitude (播放 15 倍震幅的音訊)
以不同采用率播放（不同速度播放）% Playback at the original speed (播放 1.0 倍速度的音訊)au.signal = y; % 恢复震幅audioPlay(au);% Playback at 0.8 times the original speed (播放 0.8 倍速度的音訊)au.fs = 0.8*fs;audioPlay(au);% 播放 0.5 倍速度的音訊，像牛叫的声音au.fs = 0.5*fs;audioPlay(au);% Playback at 1.2 times the original speed (播放 1.2 倍速度的音訊)au.fs = 1.2*fs;audioPlay(au);% Playback at 2 times the original speed (播放 2 倍速度的音訊) au.fs = 2*fsaudioPlay(au);
改变波形，比如把信号沿着x轴反转（y轴 * -1），再听声音， 听到的没有变化，说明声音的相位并不影响人的感知。
% Playback of the original signal (播放正常的音訊波形)au.fs = fs;au.y = y;audioPlay(au);% Playback of the up-down flipped signal (播放上下顛倒的音訊波形)au.y = - y;audioPlay(au);% Playback of the left-right flipped signal (播放前後顛倒的音訊波形)au.y = flipud(y);audioPlay(au);
使用 audioplayer, play 来播放音频文件
apObj=audioplayer(y, fs);apObj.SampleRate=16000;% Change the sample rate to 16000play(apObj);% 可以使用 doc play, doc audioplayer 来查看在线帮助，也可以使用 help 看命令行帮助。
录制音频文件% The commands wavplay and wavrecord are only supported in Microsoft Windows platform.% audiorecorder(Fs, NBITS, NCHANS) creates an audiorecorder object fs=16000;% Sampling rate (取樣頻率)% duration=2;% Recording duration (錄音時間)fprintf('Press any key to start %g seconds of recording...', duration); pausefprintf('Recording...');% y=wavrecord(duration*fs, fs);% duration*fs is the total number of sample points% record audio, sample rate of fs, and 16 bit, 1 channelr = audiorecorder(fs, 16, 1)record(r)% 等待一定时间stop(r)fprintf('Finished recording.n');fprintf('Press any key to play the recording...'); pause; fprintf('n');p = play(r);
前面的 record() 函数是异步录制， 执行之后代码继续运行，知道 stop()。 也可以同步录制，示例如下。
同步指定时长录制音频文件（录制5s）fs=16000; % Sampling rate r = audiorecorder(fs, 16, 1) % sample rate of fs, and 16 bit, 1 channelrecordblocking(r, 5); % speak into microphone...fprintf('Finished recording.n');fprintf('Press any key to play the recording...'); pause; fprintf('n');p = play(r);
保存录制的音频文件可以通过如下代码，将前面录制的数据保存到 wav 文件。
% 保存录制的音频到文件% nbits=16; % Bit resolution (每个采样点的信号量， 量化值的位数为 16-bit)waveFile='test.wav';% Wav file to be saved% get sample data from recorder, get data as int16 array:y = getaudiodata(r, 'int16'); % writes data Y to an audio file with name FILENAME, with a sample rate of FS Hz.% AUDIOWRITE(FILENAME,Y,FS) audiowrite(waveFile, y, fs);fprintf('Finished writing %sn', waveFile);