用Matlab听音乐 - 动态频谱

高帧率版本

由于matlab这款科学计算软件本身庞大略显笨重，执行代码的速度受当前系统影响，很难做到严格定时仿真（造成音画不同步），因此高帧率版本的音画同步需要调整：

for i = 1:floor(fs/75):length(data)
    if i+0.1*fs<length(data)
        X = data(i:floor(i+0.1*fs),1);

中fs/75的步长数值，以及0.1*fs窗移步长权重，根据经验调参出适合本地系统的同步效果。

clc,clear,close all;
[data, fs]=audioread('see u again.wav');
player = audioplayer(data,fs);
play(player);
figure('Name', 'The Chainsmokers - See You Again');
subplot(121)
wallpaper = imread('see u again.jpg');
imshow(wallpaper);
axis off
for i = 1:floor(fs/75):length(data)
    if i+0.1*fs<length(data)
        X = data(i:floor(i+0.1*fs),1);  
    else 
        break
    end
    L = length(X);
    Y = fft(X); %Y为复数
    P1 = abs(Y/L); %取模
    freq1 = fs*(0:L-1)/L; %频域范围

    P3 = P1(1:floor(L/2)+1);  %索引必须从1开始
    freq3 = fs*(0:floor(L/2))/L;

    nbins = 256; %将频域波分nbins份
    window = floor(length(freq3)/nbins);
    %平滑数据
    P4 = smooth(P3, window);
    P5 = P4(1:window:end);
    freq4 = freq3(1:window:end); 
    subplot(122)
    bar3(freq4,P5);
    view(290,45)
    axis off
    drawnow
end

效果:

定时器版本

通过使用matlab定时器，实现严格的帧刷新效果；
缺点是比较卡顿。

具体教程参考：江流不染 - matlab音乐频谱动画

music_play主函数：

clc,clear,close all;
%全局句柄
global music;
%Fs为每秒采样点数44100
[data, Fs] = audioread('see u again.wav');
% 音频长度
total_frame = size(data,1);
% 更新音乐播放器
music = audioplayer(data, Fs);
% 初始化画布
figure('Name', 'The Chainsmokers - See You Again')
subplot(121)
wallpaper = imread('see u again.jpg');
imshow(wallpaper);
axis off
subplot(122)
bar3(0, 0);
% 限制Y轴显示范围
ylim([0, 0.2]);
% 视角
view(290,45)
% 创建一个定时器。
t = timer('Period', 0.1, 'TimerFcn', {@timer_callback,data,Fs,total_frame},'ExecutionMode','fixedSpacing');
% 启动定时器，每隔Period调用一帧动画
start(t);
% 进行播放
play(music);

定时器回调函数：

%定时器回调函数
function timer_callback(object, eventdata, data,Fs,total_frame)% 前两个参数不能省略，必填，其中第一个参数代表定时器本身
    global music;
    Current = music.CurrentSample;
    %确定取样范围
    half_space = floor(0.1*Fs/2);
    left = Current - half_space;
    if left<1
       left = 1;
    end
    right = Current + half_space;
    if right>total_frame
       right = total_frame;
    end
    X = data(left:right,:);
    % 将音频左右声道合并
    X = sum(X, 2);
    L = length(X);
    % 快速傅里叶fft
    Y = fft(X);
    P1 = abs(Y/L);
    % 合并，乘以2。
    P2 = 2*P1(1:floor(L/2)+1);
    freq2 = Fs*(0:floor(L/2))/L;
    P2 = P2(freq2>20&freq2<12000);
    freq2 = freq2(freq2>20&freq2<12000);
    % 分为nbins份
    nbins = 128;
    % 每一份的宽度
    window = floor(length(freq2)/nbins);
    % 平滑数据
    P3 = smooth(P2, window);   
    P4 = P3(1:window:end);
    freq3 = freq2(1:window:end);
    %更新句柄属性
    bar3(freq3, P4);
    axis off;
end

效果:

用Matlab听音乐 - 钱斯莫克 & ILLENIUM/Carlie Hanson - See You Again

三维动画版本

clc,clear,close all;
%全局句柄
global music;
%Fs为每秒采样点数44100
[data, Fs] = audioread('selfds.mp3');
% 音频长度
total_frame = size(data,1);
% 更新音乐播放器
music = audioplayer(data, Fs);
% 初始化画布
figure('Name', 'The Chainsmokers - Self Destruction Mode')
subplot(121)
wallpaper = imread('self destruction mode.jpg');
imshow(wallpaper);
axis off
subplot(122)
axis off;
% 创建一个定时器。
t = timer('Period', 0.01, 'TimerFcn', {@timer_callback2,data,Fs,total_frame},'ExecutionMode','fixedSpacing');
% 启动定时器，每隔Period调用一帧动画
start(t);
% 进行播放
play(music);

%定时器回调函数
function timer_callback2(object, eventdata, data,Fs,total_frame)% 前两个参数不能省略，必填，其中第一个参数代表定时器本身
    global music;
    Current = music.CurrentSample;
    %确定取样范围
    half_space = floor(0.1*Fs/2);
    left = Current - half_space;
    if left<1
       left = 1;
    end
    right = Current + half_space;
    if right>total_frame
       right = total_frame;
    end
    X = data(left:right,:);
    % 将音频左右声道合并
    X = sum(X, 2);
    L = length(X);
    % 快速傅里叶fft
    Y = fft(X);
    P1 = abs(Y/L);
    % 合并，乘以2。
    P2 = 2*P1(1:floor(L/2)+1);
    freq2 = Fs*(0:floor(L/2))/L;
    P2 = P2(freq2>20&freq2<12000);
    freq2 = freq2(freq2>20&freq2<12000);
    % 分为nbins份
    nbins = 128;
    % 每一份的宽度
    window = floor(length(freq2)/nbins);
    % 平滑数据
    P3 = smooth(P2, window);   
    P4 = P3(1:window:end);
    freq3 = freq2(1:window:end);
    %更新句柄属性
    r = linspace(0,2*pi,length(freq3));
    s = linspace(0,pi,length(freq3));
    [u,v] = meshgrid(r,s);
    x = (2+cos(v)).*cos(u);
    y = (2+cos(v)).*sin(u);
    z = 128*P4.*sin(u);
    mesh(x,y,z);
    colormap hot;
    axis equal;
    axis off;
end

效果：

用Matlab听音乐 -钱斯莫克 - Self Destruction Mode