Cannot find an exact (case-sensitive) match for 'getFrame' ?

I use matlab R2018b and Iwant to display a video in axes using app designer this is my code:

 function importervideoButtonPushed(app, event)
            % to import some thing
            [a, b]= uigetfile({'*.*'});
            vid = VideoReader([b a]);
            while hasFrame(vid)
                imshow(getFrame(vid), 'Parent', app.UIAxes1);
            end
 end

but when I push on the button the following error is written

what should I do ?

[Walter Roberson]

Try

            vid = VideoReader(fullfile(b,a);

uigetfile is not certain to put a trailing directory delimiter on the directory returned, so you might have been constructing a path to a file that did not exist.

[LEKHCHINE Somia]

Actually I tried the program but it did not work and that's the errors:

Error using metaclass
Error: File: app1.mlapp Line: 25 Column: 44
Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.

Error in appdesigner.internal.service.AppManagementService/isBadNumberOfArguments (line 256)
            appMetaData = metaclass(app);

Error in appdesigner.internal.service.AppManagementService/tryCallback (line 340)
                if (obj.isBadNumberOfArguments(app, exception))

Error in matlab.apps.AppBase>@(source,event)tryCallback(appdesigner.internal.service.AppManagementService.instance(),app,callback,requiresEventData,event)
 
Error using matlab.ui.control.internal.controller.ComponentController/executeUserCallback (line 335)
Error while evaluating Button PrivateButtonPushedFcn.

Error using metaclass
Error: File: app1.mlapp Line: 25 Column: 44
Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.

Error in appdesigner.internal.service.AppManagementService/isBadNumberOfArguments (line 256)
            appMetaData = metaclass(app);

Error in appdesigner.internal.service.AppManagementService/tryCallback (line 340)
                if (obj.isBadNumberOfArguments(app, exception))

Error in matlab.apps.AppBase>@(source,event)tryCallback(appdesigner.internal.service.AppManagementService.instance(),app,callback,requiresEventData,event)
 
Error using matlab.ui.control.internal.controller.ComponentController/executeUserCallback (line 335)
Error while evaluating Button PrivateButtonPushedFcn.

The previous instruction of importing was working

[Walter Roberson]

What is the content of line 25 of app1.mlapp ?

[LEKHCHINE Somia]

 vid = VideoReader(fullfile(b,a);

[LEKHCHINE Somia]

My object is to import video and play it in axes using app desinger, so fisrt I try to test if the import instruction work and I write the following code:

            [a, b]= uigetfile({'*.*'});
            vid = VideoReader([b a]);
            implay(vid);

and it realy show the video but I want to display it into the axes (app designer).

[Walter Roberson]

The line

 vid = VideoReader(fullfile(b,a);

is missing a )

[Walter Roberson]

Remember to put in a drawnow() after the imshow()

Also, imshow() is a fairly expensive operation. It is better (faster) to create a image() object and set the the CData property of the object.

[LEKHCHINE Somia]

I did everything I had to do and all the instructions that you told me and the same first error

Cannot find an exact (case-sensitive) match for 'getFrame'

The closest match is: getframe in C:\Program Files\MATLAB\R2018b\toolbox\matlab\graphics\getframe.m


Error in app1/importervideoButtonPushed (line 27)
                imshow(getFrame(vid),'Parent',app.UIAxes1);
 
Error using matlab.ui.control.internal.controller.ComponentController/executeUserCallback (line 335)
Error while evaluating Button PrivateButtonPushedFcn.

Answer 1

[Walter Roberson]

 function importervideoButtonPushed(app, event)
            % to import some thing
            [a, b]= uigetfile({'*.*'});
            vid = VideoReader([b a]);
            first = true;
            while hasFrame(vid)
                thisframe = readFrame(vid);
                if first
                  img = imshow(thisFrame, 'Parent', app.UIAxes1);
                  first = false;
                else
                  img.CData = thisframe;
                end
                drawnow();
            end
 end

[LEKHCHINE Somia]

It is my first experiance with matlab so please be patient with me

I put exactly your code but there is an error:

Undefined function or variable 'thisFrame'.

Error in app1/importervideoButtonPushed (line 31)
                  img = imshow(thisFrame, 'Parent', app.UIAxes1);
 
Error using matlab.ui.control.internal.controller.ComponentController/executeUserCallback (line 335)
Error while evaluating Button PrivateButtonPushedFcn.

[Walter Roberson]

 function importervideoButtonPushed(app, event)
            % to import some thing
            [a, b]= uigetfile({'*.*'});
            vid = VideoReader([b a]);
            first = true;
            while hasFrame(vid)
                thisframe = readFrame(vid);
                if first
                  img = imshow(thisframe, 'Parent', app.UIAxes1);
                  first = false;
                else
                  img.CData = thisframe;
                end
                drawnow();
            end
 end

Answer 2

[LEKHCHINE Somia]

thank you so much and I hope God protects you

but I just declare this frame as private properties and replace it with app.this frame

[Walter Roberson]

I guess you could do that, but it should not be needed, not unless you want to access the last frame of the video after the video is played.