Incorrectly getting a blank video when using videowriter function to display data
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Hello, I am having a difficulty with writing and displaying a video for data that is meant to represent multiple frames that have been corrected for motion. I am essentially stabilizing the motion of a "shaky" video. I am still learning how to use Matlab within my research so this could be lack of coding experience on my end.
I am not receiving any error message but rather getting a video output of a blank video. In the first section, I am correcting the frame offsets. "Stabilized" should be the data used that I want to represent in a movie. When calling on it as a singular and averaged frames figure, I receive what I expect. The "Stabilized" file contains Y axis, X axis, RGB, and number of frames. The second section is my attempt to write a movie of my data which is where I believe I might be doing it incorrectly. I followed the examples provided in youtube and under "Help: Videowriter" in the command row, but nothing has worked. If more information is needed, please do not hesistate to ask. I greatly appreciate the help.

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Accepted Answer
Walter Roberson
on 28 Sep 2022
You are not changing the display between getframe() so all of the frames would be the same.
If you have pre-computed frames stored in stabilized then write them directly, like
for i = 1 : size(stabilized,3)
currFrame = stabilized(:,:,:,i);
writeFrame(vidObj, currFrame);
end
And... you should be sure to initialize stabilized to the appropriate data type, such as
stabilized = zeros([2 2 1 1].*size(video), 'like', video);
which I suspect was the major source of your problem with the output being white.
11 Comments
Walter Roberson
on 3 Oct 2022
With regards to the 'like' option, see https://www.mathworks.com/help/matlab/matlab_oop/class-support-for-array-creation-functions.html for more details on how like is implemented for classes.
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