Matrix digital rain (raining code) with a message emerging i

This file generates a video just like the Matrix digital rain with a message emerging in the end.

You can embed any message you want for your special one within the cool Matrix digital rain. The code is fully customizable and fully vectorized (with a single for-loop). Remember to flip the video file horizontally afterwards to get the mirrored characters! Here is an example of the generated video (https://youtu.be/Y_LXY7TGnWA).
To reproduce the visual effect of the Matrix digital rain, the following features are incorporated:
(1) Randomized rain length
(2) Randomized rain falling speed
(3) Head effect: the first 3 characters of each rain are brighter and whiter
(4) Tail effect: the brightness of the trailing characters of each rain fade gradually
(5) Randomized tail length
(6) Rain characters change randomly at a given rate
(7) Rain characters have randomized brightness
The rendering with the default parameters take about 20 mins, so be patient. Matlab text() function is not fast.