Text with moving letters¶
I think this example illustrates well the interest of script-based editing (imagine doing that by hand).
Here is the code:
import numpy as np
from moviepy import *
from moviepy.video.tools.segmenting import find_objects
# WE CREATE THE TEXT THAT IS GOING TO MOVE, WE CENTER IT.
screensize = (720, 460)
txtClip = TextClip(
"Cool effect", color="white", font="Amiri-Bold", kerning=5, font_size=100
)
cvc = CompositeVideoClip([txtClip.with_position("center")], size=screensize)
# THE NEXT FOUR FUNCTIONS DEFINE FOUR WAYS OF MOVING THE LETTERS
# helper function
rotMatrix = lambda a: np.array([[np.cos(a), np.sin(a)], [-np.sin(a), np.cos(a)]])
def vortex(screenpos, i, nletters): # noqa D103
d = lambda t: 1.0 / (0.3 + t**8) # damping
a = i * np.pi / nletters # angle of the movement
v = rotMatrix(a).dot([-1, 0])
if i % 2:
v[1] = -v[1]
return lambda t: screenpos + 400 * d(t) * rotMatrix(0.5 * d(t) * a).dot(v)
def cascade(screenpos, i, nletters): # noqa D103
v = np.array([0, -1])
d = lambda t: 1 if t < 0 else abs(np.sinc(t) / (1 + t**4))
return lambda t: screenpos + v * 400 * d(t - 0.15 * i)
def arrive(screenpos, i, nletters): # noqa D103
v = np.array([-1, 0])
d = lambda t: max(0, 3 - 3 * t)
return lambda t: screenpos - 400 * v * d(t - 0.2 * i)
def vortexout(screenpos, i, nletters): # noqa D103
d = lambda t: max(0, t) # damping
a = i * np.pi / nletters # angle of the movement
v = rotMatrix(a).dot([-1, 0])
if i % 2:
v[1] = -v[1]
return lambda t: screenpos + 400 * d(t - 0.1 * i) * rotMatrix(-0.2 * d(t) * a).dot(
v
)
# WE USE THE PLUGIN find_objects TO LOCATE AND SEPARATE EACH LETTER
letters = find_objects(cvc) # a list of ImageClips
# WE ANIMATE THE LETTERS
def moveLetters(letters, funcpos): # noqa D103
return [
letter.set_pos(funcpos(letter.screenpos, i, len(letters)))
for i, letter in enumerate(letters)
]
clips = [
CompositeVideoClip(moveLetters(letters, funcpos), size=screensize).subclip(0, 5)
for funcpos in [vortex, cascade, arrive, vortexout]
]
# WE CONCATENATE EVERYTHING AND WRITE TO A FILE
final_clip = concatenate_videoclips(clips)
final_clip.write_videofile("../../coolTextEffects.avi", fps=25, codec="mpeg4")