Python 视频转场特效处理笔记
本文参考Python-OpenCV 实现美图秀秀视频剪辑效果【特效】_opencv 多张图片 视频 特效-CSDN博客
最近研究了点python处理视频相关的东西，本文展示特效包括，竖向开幕/横向开幕，渐隐/渐显，推近/拉远，方形开幕，灰度渐变。不多说，直接上代码。
import cv2
import numpy as np
import random
def addCardFrame(video_writer,img,backimg=None,fps=18,sec=1,eachtime=0.5):
"""视频特效:卡帧"""
rows, cols = img.shape[:2]
'''缩放原图80%'''
img = cv2.resize(img, (int(cols * 0.8),int(rows * 0.8)))
rows_new, cols_new = img.shape[:2]
'''准备更大的画布'''
cav = None
if backimg is None:
cav_np = np.zeros((rows, cols), np.uint8)
cav = cv2.cvtColor(cav_np, cv2.COLOR_GRAY2BGR)
else:
cav = backimg
'''偏移量准备'''
dic = {
0: (int(cols * 0.08), int(rows * 0.12)),
1: (int(cols * 0.10), int(rows * 0.10)),
2: (int(cols * 0.12), int(rows * 0.08)),
3: (int(cols * 0.12), int(rows * 0.07)),
4: (int(cols * 0.12), int(rows * 0.06)),
5: (int(cols * 0.14), int(rows * 0.07)),
6: (int(cols * 0.16), int(rows * 0.07)),
7: (int(cols * 0.15), int(rows * 0.09)),
8: (int(cols * 0.14), int(rows * 0.10)),
9: (int(cols * 0.14), int(rows * 0.07)),
10: (int(cols * 0.13), int(rows * 0.05)),
11: (int(cols * 0.14), int(rows * 0.06)),
12: (int(cols * 0.14), int(rows * 0.08)),
13: (int(cols * 0.15), int(rows * 0.10)),
14: (int(cols * 0.14), int(rows * 0.09)),
15: (int(cols * 0.12), int(rows * 0.12)),
16: (int(cols * 0.10), int(rows * 0.10)),
17: (int(cols * 0.08), int(rows * 0.12))
}
'''添加特效展示'''
for _ in range(int(sec)):
xs, ys = dic[random.randrange(0,18,1)]
xe, ye = (xs + rows_new, ys + cols_new)
cav[xs: xe, ys: ye] = img
for _ in range(int(eachtime*fps)):
video_writer.write(cav)
def addVerticalOpening(video_writer,img,backimg=None,fps=18,sec=1,mode='H'):
"""视频特效:竖向开幕H 横向开幕V"""
rows, cols = img.shape[:2]
'''画布准备'''
cav = None
if backimg is None:
cav_np = np.zeros((rows, cols), np.uint8)
cav = cv2.cvtColor(cav_np, cv2.COLOR_GRAY2BGR)
else:
cav = backimg
'''特效展示'''
load_f = 1000/fps
n = 5
height_half,weight_half = int(rows / 2),int(cols / 2)
xs1, xs2 = height_half, height_half
xe1, xe2 = height_half, height_half
ys1, ys2 = weight_half, weight_half
ye1, ye2 = weight_half, weight_half
for t in range(int(sec*1000 // load_f)):
load_percent = 0.5 / (sec ** n) * ((sec - t * load_f / 1000) ** n)
if mode=='H':
load_height = int((0.5 - load_percent) * rows)
xe1, xe2 = height_half - load_height, height_half + load_height
cav[xe1:xs1, :] = img[xe1:xs1, :]
cav[xs2:xe2, :] = img[xs2:xe2, :]
xs1, xs2 = xe1, xe2
else:
load_weight = int((0.5 - load_percent) * cols)
ye1, ye2 = weight_half - load_weight,weight_half + load_weight
cav[:, ye1:ys1] = img[:, ye1:ys1]
cav[:, ys2:ye2] = img[:, ys2:ye2]
ys1, ys2 = ye1, ye2
video_writer.write(cav)
def addFadeOut(video_writer,img,backimg=None,fps=18,sec=2):
"""视频特效:渐隐"""
'''特效展示'''
load_f = 1000/fps
n = 1
for t in range(int(sec * 1000 // load_f)):
sc = 1 - 1 / (sec ** n) * (t * load_f / 1000) ** n
img_show = cv2.multiply(img, (1, 1, 1, 1), scale=sc)
video_writer.write(img_show)
def addFadeIn(video_writer,img,fps=18,sec=2):
"""视频特效:渐隐"""
'''特效展示'''
load_f = 1000/fps
n = 1.5
for t in range(int(sec * 1000 // load_f)):
sc = 1 - 1 / (sec ** n) * (t * load_f / 1000) ** n
sc = 1 - 1 / (sec ** n) * (sec - t * load_f / 1000) ** n
img_show = cv2.multiply(img, (1, 1, 1, 1), scale=sc)
video_writer.write(img_show)
def percent_func_gen(a, b, time, n, mode):
"""
高次多项式计算函数生成器
:param a: 起始百分比（如：0.25）
:param b: 结束百分比
:param time: 动画持续时间
:param n: 多项式次数
:param mode: faster（越来越快）、slower（越来越慢）
:return: 每个时刻到达百分比的计算函数
"""
if mode == "slower":
a, b = b, a
delta = abs(a - b)
sgn = 1 if b - a > 0 else (-1 if b - a < 0 else 0)
def percent_calc(ti):
if mode == "slower":
ti = time - ti
return sgn * delta / (time ** n) * (ti ** n) + a
return percent_calc
def addAdvance(video_writer,img,fps=18,sec=2):
"""视频特效:推近"""
rows, cols = img.shape[:2]
'''特效展示'''
load_f = 1000/fps
percent_func = percent_func_gen(a=0, b=0.2, time=sec, n=4, mode="slower")
for t in range(int(sec * 1000 // load_f + 1)):
percent = percent_func(t * load_f / 1000)
xs, xe = int(percent * rows), int((1 - percent) * rows)
ys, ye = int(percent * cols), int((1 - percent) * cols)
img_show = img[xs:xe, ys:ye]
img_show = cv2.resize(img_show, (cols,rows))
video_writer.write(img_show)
def addZoomOut(video_writer,img,fps=18,sec=2):
"""视频特效:拉远"""
rows, cols = img.shape[:2]
'''特效展示'''
load_f = 1000/fps
percent_func = percent_func_gen(a=0.2, b=0, time=sec, n=3, mode="slower")
for t in range(int(sec * 1000 // load_f + 1)):
percent = percent_func(t * load_f / 1000)
xs, xe = int(percent * rows), int((1 - percent) * rows)
ys, ye = int(percent * cols), int((1 - percent) * cols)
img_show = img[xs:xe, ys:ye]
img_show = cv2.resize(img_show, (cols,rows))
video_writer.write(img_show)
def addSquareOpening(video_writer,img,backimg=None,fps=18,sec=2):
"""视频特效:方形开幕"""
rows, cols = img.shape[:2]
'''画布准备'''
cav = None
if backimg is None:
cav_np = np.zeros((rows, cols), np.uint8)
cav = cv2.cvtColor(cav_np, cv2.COLOR_GRAY2BGR)
else:
cav = backimg
'''特效展示'''
load_f = 1000/fps
percent_func = percent_func_gen(a=0, b=0.5, time=sec, n=5, mode="faster")
rows_half = rows // 2
cols_half = cols // 2
for t in range(int(sec * 1000 // load_f + 1)):
percent = percent_func(t * load_f / 1000)
width, height = int(percent * rows), int(percent * cols)
xs, xe = rows_half-width, rows_half+width
ys, ye = cols_half-height, cols_half+height
cav[xs:xe, ys:ye] = img[xs:xe, ys:ye]
video_writer.write(cav)
def addGradientWipe(video_writer,img,backimg=None,fps=18,sec=2,mode='L'):
"""视频特效:灰度渐变 L左 R右 U上 D下"""
rows, cols = img.shape[:2]
'''灰度准备'''
img_gray_bgr = None
if backimg is None:
img_gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
img_gray_bgr = cv2.cvtColor(img_gray, cv2.COLOR_GRAY2BGR)
else:
img_gray_bgr = backimg
'''特效展示'''
load_f = 1000/fps
percent_func = percent_func_gen(a=0, b=1, time=sec, n=1, mode="slower")
if mode=='L':
ys, ye = 0, 0
for t in range(int(sec * 1000 // load_f + 1)):
percent = percent_func(t * load_f / 1000)
width = int(percent * cols)
ye = width
img_gray_bgr[:, ys:ye] = img[:, ys:ye]
ys = ye
video_writer.write(img_gray_bgr)
if mode=='R':
ys, ye = cols, cols
for t in range(int(sec * 1000 // load_f + 1)):
percent = percent_func(t * load_f / 1000)
width = int(percent * cols)
ys = cols-width
img_gray_bgr[:, ys:ye] = img[:, ys:ye]
ye = ys
video_writer.write(img_gray_bgr)
if mode=='U':
xs, xe = 0, 0
for t in range(int(sec * 1000 // load_f + 1)):
percent = percent_func(t * load_f / 1000)
height = int(percent * rows)
xe = height
img_gray_bgr[xs:xe, :] = img[xs:xe, :]
xs = xe
video_writer.write(img_gray_bgr)
if mode=='D':
xs, xe = rows, rows
for t in range(int(sec * 1000 // load_f + 1)):
percent = percent_func(t * load_f / 1000)
height = int(percent * rows)
xs = cols-height
img_gray_bgr[xs:xe, :] = img[xs:xe, :]
xe = xs
video_writer.write(img_gray_bgr)调用方法进行视频合成
fps = 25 #视频帧数
sec = 3 # 特效时间
eachtime = 0.5 # 每帧所占时间
video_temp_path= "test.mp4"
img1 = cv2.imread("0.jpg")
img2 = cv2.imread("1.jpg")
img3 = cv2.imread("2.jpg")
video_height,video_weight =img.shape[:2]
video_writer = cv2.VideoWriter(video_temp_path, cv2.VideoWriter_fourcc(*'mp4v'), fps, (video_weight,video_height))
addCardFrame(video_writer,img1,fps,sec,eachtime)
addVerticalOpening(video_writer,img2,img1,fps,sec,mode='V')
addFadeOut(video_writer,img3,fps,sec)
addFadeIn(video_writer,img1,fps,sec)
addAdvance(video_writer,img2,fps,sec)
addZoomOut(video_writer,img3,fps,sec)
addSquareOpening(video_writer,img2,img3,fps,sec)
addGradientWipe(video_writer,img1,img2,fps,sec,mode='D')
video_writer.release()视频效果如下：
