Blender altering colours after video sequencing

I have noticed that Blender cannot render images as the way they are. Everytime when I compile my image sequences into an MP4 video file, I can notice slight color differences compared to the original images. Colour management has been set to standard and no curves are enabled. In this scene of mine, the colours are altered quite obviously and I cannot let it slide this time. Does anyone know what’s causing this?

The first image shows how the colours should be.
The last image shows how the colours look like while playing the compiled video file. (If you can’t tell, the green in the altered image is darker than it should be)