MATLAB: How to write a video file with analog plots

data acquisitionMATLABplotplottingsubplotvideo

I would like to write a graph to a video file.
It was succeeded to make a video to recode a graph with the following simple code, but I have no idea how this program is applicable to my program.
Though I tried to edit my code to recode plotting data for ten seconds of video, the file size of the video was 0 KB.
How should I fix my code?
Simple Code to create a video file from a graph
x = 0:100;
y = sin(x);
writerObj = VideoWriter('test.avi');
open(writerObj);
fig = plot(x,y);
set(fig, 'XDataSource', 'x');
set(fig, 'YDataSource', 'y');
set(gca, 'Xlim', [0 100], 'Ylim', [-20 20]);
set(gca,'nextplot','replacechildren');
for k = 0:20
    y = k*sin(x);
    refreshdata(fig);
    frame = getframe(gcf);
    writeVideo(writerObj, frame);
end
close(writerObj);
My Code
writerObj = VideoWriter('graph.avi');
open(writerObj);
tx = daq.createSession('ni');
s = daq.createSession('ni');
s.Rate = 400000;
ultraFreq = 40000;
numCycle =8
y = [y zeros(1,numCycle*s.Rate/ultraFreq)];
addAnalogOutputChannel(tx, 'Dev1', 'ao0', 'Voltage');
th=addlistener(tx, 'DataRequired', @queueMoreData);
addAnalogInputChannel(s,'Dev1', 'ai0', 'Voltage'); 
ch = addAnalogInputChannel(s, 'Dev1', 'ai1', 'Voltage'); 
h = addlistener(s, 'DataAvailable', @plotData); 
s.DurationInSeconds(1);
queueOutputData(tx, y');
startBackground(s);
tx.startForeground();
function plotData(src, event)
  t1 = event.TimeStamps(:,1);
  s1 = event.Data(:,1);
  s2 = event.Data(:,2);
  subplot(2,1,1)
  plot(t1,s1)
  ylim([-10.0 10.0]);
  title('s_1')
  
  subplot(2,1,2)
  plot(t1,s2)
  ylim([-10.0 10.0]);
  title('s_2')
  xlabel('Time (s)')
  while(10)
    frame = getframe(gcf);
    writeVideo(writerObj, frame)
end
function queueMoreData(src, event)
  queueOutputData(tx, y');
end

Best Answer

function plot_session
    recording_time = 300;    %seconds
    
    ax1 = subplot(2,1,1);
    L1 = animatedline(ax1);
    ylim(ax1, [-10.0 10.0]);
    title(ax1, 's_1')
    xlabel(ax1, 'Time (s)')
    
    ax2 = subplot(2,1,2);
    L2 = animatedline(ax2);
    ylim(ax2, [-10 10.0]);
    title(ax2, 's_2')
    xlabel(ax2, 'Time (s)')
    
    writerObj = VideoWriter('graph.avi');
    open(writerObj);
    
    tx = daq.createSession('ni');
    s = daq.createSession('ni');
    s.Rate = 400000;
    ultraFreq = 40000;
    numCycle = 8;
    
    y = [y zeros(1,numCycle*s.Rate/ultraFreq)];
    addAnalogOutputChannel(tx, 'Dev1', 'ao0', 'Voltage');
    th = addlistener(tx, 'DataRequired', @queueMoreData);
    addAnalogInputChannel(s,'Dev1', 'ai0', 'Voltage'); 
    ch = addAnalogInputChannel(s, 'Dev1', 'ai1', 'Voltage'); 
    h = addlistener(s, 'DataAvailable', @plotData); 
    s.DurationInSeconds(1);
    queueOutputData(tx, y');
    
    startBackground(s);
    tx.startForeground();
    
    pause(recording_time)
    
    %cleanup time
    delete(th)
    delete(h)
    pause(1);   %time for last plot event
    close(writerObj);
    delete(s)
    delete(tx)
    
    function plotData(src, event)
      t1 = event.TimeStamps(:,1);
      s1 = event.Data(:,1);
      s2 = event.Data(:,2);
      addpoints(L1, t1, s1);
      addpoints(L2, t1, s2);
      drawnow();
      pause(0.05);  %in practice need time to render
      frame = getframe(gcf);
      writeVideo(writerObj, frame)
    end
    
    function queueMoreData(src, event)
      queueOutputData(tx, y');
    end
end
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