Displaying video in a App Designer's tab

I want to display a live video preview in app made by App Designer, using preview(), but I don't want it to create seperate window, just display the image in one of the tabs. Is it even possible using App Designer. Do I have to create any objects to make it possible?

[Kevin Chng]

I guess yes.

In your callback function of play button:

for i=1:1:length(yourimage)
   imshow(yourimage(i),'Parent',app.UIAxes');
   drawnow
   pause(0.01) % might not necessary if your gui updating speed is nice to you
end

You may stream your webcam as well. features like play,rewind,forward,pause , you may refer to the link below:

https://www.mathworks.com/matlabcentral/answers/417527-play-pause-rewind-and-fast-forward-buttons-app-designer

[Michal Wieczorek]

Thank you for response. Why I asked about using preview() to display image is the fact, that it does not affect framerate. Drawing a figure drops it significantly. Also the loop is probably not set correctly, because it seemed that the figure displays only one streched pixel in greyscale. I've developed code that allows us to draw figures based on the video input:

vid = videoinput(adaptorname,deviceID,format);
          for i=1:(no of frames you want to display)
              img = getsnapshot(vid);
              imshow(img,'Parent',app.UIAxes');
              drawnow
              pause(0.01) % might not necessary if your gui updating speed is nice to you
          end

I wonder if you know any way to make displaying more prompt.

[Kevin Chng]

it does not affect framerate

You are right, it make me headache sometimes on the inconsistent updating frame rate. I use tic(),toc() and pause().

for loop
tic()

time=toc()
let say you wannt maintain it 0.1 updating rate
pause(0.1-time)
end

However it must ensure 0.1-time is not negative value.

How to make your updating rate faster?

In my memory, i use cla(axes,'reset') in the loop, clear some unused variables, and make the code in the loop more simple and straight forward.

Or,

sacrifice some of your frame to make your display look like faster in playing.

Or,

I heard system object may help, but i haven tried it.

[Kevin Chng]

Michael Wieczorek,

If you want your video running faster, you may consider programmatically GUI instead of app designer.

Answer 1

[Ahmer Shahid]

I am using the above code but this very slowly works I want to run it fastly as a live camera. Thanks in advance.

[Kevin Chng]

Are you using App Designer? Put your question/comment below the original question instead of putting it in answer box.

[Ahmer Shahid]

Yes I am using App Designer and I want to preview camera on an axis.

[Kevin Chng]

I'm not sure with other's opinion. But if you use programmatically GUI, it will be much more faster without the lag in app designer.

https://www.mathworks.com/matlabcentral/fileexchange/24861-41-complete-gui-examples