How to make a Video from 3D array

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Hamed Bolandi
Hamed Bolandi on 22 Jul 2021
Commented: Hamed Bolandi on 23 Jul 2021
I have 3D matrix with dimension of 600x600x28 which the last index is number of frames and want to convert it to video file. I tried as a below but raised with error:
Unrecognized function or variable 'cmap'.
My code:
Orig = rand(600,600,28);
X = permute(Orig,[1 2 4 3]); % 4D matrix
movie = immovie(X,cmap);
implay(movie);

Answers (1)

millercommamatt
millercommamatt on 22 Jul 2021
You never defined the variable cmap which is supposed to be a color map.
Try This:
Orig = rand(600,600,28);
camp=parula;
X = permute(Orig,[1 2 4 3]); % 4D matrix
movie = immovie(X,cmap);
implay(movie);
  3 Comments
millercommamatt
millercommamatt on 23 Jul 2021
I get the same error and I don't know why. The documentation for immovie says that double is an allowable input data type.
But, I have a fix: Do the conversion of the input array to uint8 yourself.
Orig = randi(256,600,600,28)-1; % 0-255
cmap=parula;
X = permute(Orig,[1 2 4 3]); % 4D matrix
movie = immovie(uint8(X),cmap);
implay(movie);
Hamed Bolandi
Hamed Bolandi on 23 Jul 2021
The reason I was getting this error is because the function call immovie(X,map) requires X to be an indexed image. It means that the values of X must greater than 1. Therefore, changing the code like below solved the issue:
Orig = randi([1 255],600,600,1,28);
cmap=parula;
movie = immovie(Orig,cmap);
implay(movie);

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