Python 视频转场特效处理笔记

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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 randomdef 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 = Noneif 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] = imgfor _ 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 = Noneif 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/fpsn = 5height_half,weight_half = int(rows / 2),int(cols / 2)xs1, xs2 = height_half, height_halfxe1, xe2 = height_half, height_halfys1, ys2 = weight_half, weight_halfye1, ye2 = weight_half, weight_halffor 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_heightcav[xe1:xs1, :] = img[xe1:xs1, :]cav[xs2:xe2, :] = img[xs2:xe2, :]xs1, xs2 = xe1, xe2else:load_weight = int((0.5 - load_percent) * cols)ye1, ye2 = weight_half - load_weight,weight_half + load_weightcav[:, ye1:ys1] = img[:, ye1:ys1]cav[:, ys2:ye2] = img[:, ys2:ye2]ys1, ys2 = ye1, ye2video_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/fpsn = 1for t in range(int(sec * 1000 // load_f)):sc = 1 - 1 / (sec ** n) * (t * load_f / 1000) ** nimg_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/fpsn = 1.5for t in range(int(sec * 1000 // load_f)):sc = 1 - 1 / (sec ** n) * (t * load_f / 1000) ** nsc = 1 - 1 / (sec ** n) * (sec - t * load_f / 1000) ** nimg_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, adelta = 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 - tireturn sgn * delta / (time ** n) * (ti ** n) + areturn percent_calcdef 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/fpspercent_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/fpspercent_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 = Noneif 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/fpspercent_func = percent_func_gen(a=0, b=0.5, time=sec, n=5, mode="faster")rows_half = rows // 2cols_half = cols // 2for 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+widthys, ye = cols_half-height, cols_half+heightcav[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 = Noneif 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/fpspercent_func = percent_func_gen(a=0, b=1, time=sec, n=1, mode="slower")if mode=='L':ys, ye = 0, 0for t in range(int(sec * 1000 // load_f + 1)):percent = percent_func(t * load_f / 1000)width = int(percent * cols)ye = widthimg_gray_bgr[:, ys:ye] = img[:, ys:ye] ys = yevideo_writer.write(img_gray_bgr)if mode=='R':ys, ye = cols, colsfor t in range(int(sec * 1000 // load_f + 1)):percent = percent_func(t * load_f / 1000)width = int(percent * cols)ys = cols-widthimg_gray_bgr[:, ys:ye] = img[:, ys:ye] ye = ysvideo_writer.write(img_gray_bgr)if mode=='U':xs, xe = 0, 0for t in range(int(sec * 1000 // load_f + 1)):percent = percent_func(t * load_f / 1000)height = int(percent * rows)xe = heightimg_gray_bgr[xs:xe, :] = img[xs:xe, :] xs = xevideo_writer.write(img_gray_bgr)if mode=='D':xs, xe = rows, rowsfor t in range(int(sec * 1000 // load_f + 1)):percent = percent_func(t * load_f / 1000)height = int(percent * rows)xs = cols-heightimg_gray_bgr[xs:xe, :] = img[xs:xe, :] xe = xsvideo_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：