Calling videos from a folder in every iteration

Question

NAVNEET NAYAN 2020-1-19

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/500953-calling-videos-from-a-folder-in-every-iteration

评论： NAVNEET NAYAN 2020-1-20

clc;
clear all;
close all;
number=45;
strng=num2str(number);
Folder = 'D:\project\Fingerspelling pics\';
for k=1:length(strng)
    I(k)=str2num(strng(k));
    aFile = fullfile(Folder, 'I(k).mp4');
    videoFReader = vision.VideoFileReader(aFile);
    videoPlayer = vision.VideoPlayer;
        while ~isDone(videoFReader)
           frame = step(videoFReader);
           step(videoPlayer,frame);
        end
end

My aim is to play the 4th and 5th video from the 'Folder' described in the code above. But when I am running the code it is producing error, since there is no any folder with the name I(k) in the 'Folder'. I want that as the value of I(k) changes in every iteration, correspondingly the video should be played from the folder. For example :- Here value of I(k) will be 4 and 5 of type 'double' in corresponding iterations and I have also my files 4.mp4 and 5.mp4 saved in 'Folder'. Please tell me how I can call and play the videos from 'Folder' using I(k) values.

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Answer 1

Sindar 2020-1-20

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/500953-calling-videos-from-a-folder-in-every-iteration#answer_410946

在 MATLAB Online 中打开

Putting I(k) in quotes makes Matlab read it as a char instead of a variable. It is literally looking for I(k).mp4. To use the value of I(k), simply put (note the double quotes):

aFile = fullfile(Folder, I(k) + ".mp4");

Matlab automatically converts the number in I(k) into a string for addition. (But, doesn't do the same for adding to a char like '.mp4')

But, there's actually a way to simplify your code a bit, since you can directly index into the strng char:

clc;
clear all;
close all;
number=45;
strng=num2str(number);
Folder = 'D:\project\Fingerspelling pics\';
for k=1:length(strng)
    aFile = fullfile(Folder, [strng(k) '.mp4']);
    videoFReader = vision.VideoFileReader(aFile);
    videoPlayer = vision.VideoPlayer;
        while ~isDone(videoFReader)
           frame = step(videoFReader);
           step(videoPlayer,frame);
        end
end