MATLAB: 4-D uint8 , what does it mean

video processingvideo reading

Hello,
I've uploaded a video to matlab with the following code and I got this on workspace:
I want to know more about the meaning of "4-D uint8", what does it mean? what are the 4 dimentions , what is uint8 ?
what is the dimentions of the variable "frames"? How can I extract one column from the 4-D table?
Thank you 
video = VideoReader("measurment.mp4");
for(i = 1: video.NumberOfFrames)
    frames(:,:,:,i) = read(video, i);
end

Best Answer

There is a 2D for height and width of the video, which shows the resolution, the 3rd D is for example is of size 3 for RGB or of size 1 for grayscale.
This 3 dimensions would describe one image. Since you have a video, there are all those single frames in the 4th dimension one after eachother.
What you want i guess is readFrame since you use a for loop. What you did is reading the whole video into one 4D array. This would not need a loop.
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