视频画中画

预期效果

视频画中画

import cv2
import numpy as np

def frame_pip(frame1, frame2, N, w):
    "Add frame2 at the top-right corner of frame1"
    " N - the size of the top-left region"
    " w - weight og frame 2"
    offset_y = 10 # offset ot the top border
    offset_x = 20 # offset ot the right border
    
    frame2_resized = cv2.resize(frame2, (N, N))
    # Generate a circle type mask
    logo_region_mask = np.zeros((N, N, 3), dtype = np.uint8)
    # 在logo_region_mask中，以(N,N)为圆心，以N为半径画一个实心圆
    cv2.circle(logo_region_mask, (np.int(N/2),np.int(N/2)), np.int(N/2), (1,1,1), -1)

    region_tmp = w*frame2_resized + (1-w)*frame1[offset_y:(N+offset_y), -(N+offset_x):-offset_x, :]
    region_tmp = region_tmp.astype(np.uint8)
    # 先生成一个小区域logo_region
    logo_region = frame1[offset_y:(N+offset_y), -(N+offset_x):-offset_x, :]
    logo_region[logo_region_mask>0] = region_tmp[logo_region_mask>0]
    # 把小区域logo_region的值更新回img_marked
    frame1[offset_y:(N+offset_y), -(N+offset_x):-offset_x, :] = logo_region
    frame1 = frame1.astype(np.uint8)



vid_file = './video/football_ntsc.mp4'
# 1. open a video and the camera
vid_reader = cv2.VideoCapture(vid_file)

vid_capture = cv2.VideoCapture(0)

fps = 30
sz = (int(vid_reader.get(cv2.CAP_PROP_FRAME_WIDTH)),
      int(vid_reader.get(cv2.CAP_PROP_FRAME_HEIGHT)))

# 2. Open an video writer in mp4 format
fourcc = cv2.VideoWriter_fourcc('m', 'p', '4', 'v')
vid_writer = cv2.VideoWriter()
vid_writer.open('vid_pip.mp4', fourcc, fps, sz, True)

while(vid_reader.isOpened() and vid_capture.isOpened()):
    ret1, frame1 = vid_reader.read()  # 读视频一帧
    ret2, frame2 = vid_capture.read() # 读摄像头一帧
    if not(ret1) or not(ret2):
        break
    # 镜像
    # frame1 = frame1[::-1, :, :]
    # frame1 = frame1[:, ::-1, :]
    frame_pip(frame1, frame2, N=81, w=0.6)
    
    # 3. save the video via the writer
    vid_writer.write(frame1)
    
    cv2.imshow('camera', frame1)
    # wait until key strokes to break
    if cv2.waitKey(30) & 0xFF == ord('q'):
        break

# 4. close the video handlers
vid_reader.release()
vid_capture.release()
vid_writer.release()

注：可能存在的问题以及解决办法（感谢李俊杰同学）
Problem 1：同时打开视频和摄像头的时候，一开始我是用vid_readerc = cv2.VideoCapture(0)来打开摄像头，但这时报warming：[ WARN:1] global C:\projects\opencv-python\opencv\modules\videoio\src\cap_msmf.cpp (674) SourceReaderCB::~SourceReaderCB terminating async callback
Selution 1：上网搜索，也没有明确的介绍，有的说跟size有关，有的说是和版本有关系，但是改成vid_readerc = cv2.VideoCapture(0,cv2.CAP_DSHOW)就解决了，大概意思就是说：cv2.CAP_DSHOW是作为open调用的一部分传递标志。
Problem 2 ：framec = cv2.resize(framec, (100, 100))
frames = cv2.resize(frames, (640, 480))
frames[20:120, -120:-20, :] = framec
这里的(framec, (100, 100)，(frames, (640, 480)
frame后第一个表示行，第二个表示列，
但frames[20:120, -120:-20, :] = framec 第一个逗号前表示列，第二个表示行。
Selution 2：取反即可

########## 返回目录 - 信息隐藏技术（Python） ###

最后编辑于：2020.04.23 16:13:54