How can I see and modify frames in a filename.mat?

Hi, I need to see and modify the single frames of a video in .mat, but i don't know how to do that. I have

tvec: [40.0177 40.0578 40.0980 40.1381 … ]

Video: [623×1152×912×3 uint8]

Can someone help me? thanks

Answer 1

[Jan]

I assume, that ypu want to show e.g. the frame corresponding to a certain value of tvec.

Remember, that comparisons of floating point values are fragile (not only in Matlab, but in all programming languages. So determine the index at first with care:

% tvec: [40.0177 40.0578 40.0980 40.1381 … ]
% Video: [623×1152×912×3 uint8]
sizeVideo = size(Video);

wanted_t   = 40.0980;
[~, index] = min(abs(tvec - wanted_t));  % Consider rounding

Frame = Video(:, :, index, :);
Frame = reshape(Frame, sizeVideo([1,2,4]));

This RGB array can be displayed by the image command.

How you can modify it depends on what you want to do. This cannot be answered in general.

The reinserting is easy again:

Video(:, :, index, :) = Frame;  % Reshaped implicitly