how do I change the contrast of a video?

the problem is as follows:

this is the result that matlab outputs:

the same frame, but converted to video:

how can this problem be solved?

[Pavel Kuzmitsky]

as you can see in the frame from the video, the grids and the image are worse visible (the additional ring is not visible)

Answer 1

[Chandler Hall]

By default, videos are created using lossy compression which will remove fine details. Consider

img = ...
v = videowriter('filename.avi', 'Archival');
open(v);
writevideo(v, img);
close(v);

to create a video with no compression.