Question

我想使用blackMagic卡处理视频。第一步显然是捕获帧，但我不知道该怎么做。我试图使用通常的opencv代码来检测凸轮和显示框架，但它不起作用。有人知道吗？

谢谢

这是我的代码：

我正在那里录音，但没关系，这不是我想要做的主要事情我创建了一个类来设置网络摄像头的属性，但我不认为用BMCC这样做是正确的

from Capture import Capture
import cv2
import os
from src import improcess

 # video recorder


capture = cv2.VideoCapture(1)

cap = Capture(capture)
fourcc = cv2.cv.CV_FOURCC(*'MSVC')  # cv2.VideoWriter_fourcc() does not exist
video_writer = cv2.VideoWriter("C:\Users\Syllia\Videos\output3.avi", fourcc, 30.0, (640, 480))

i = 0
cap.set_brightness(25)

while(capture.isOpened()):
    # Capture frame-by-frame

    ret, frame = cap.cap.read()
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    if(i==120):  
        cap.adjust_brightness(100, frame)
    if i >= 240 and i<360:
        frame = improcess.binarize(170, frame)

    if i>360:
        frame = gray


    video_writer.write(frame)
    cv2.imshow('frame',frame)
    i = i+1

    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

# When everything done, release the capture
video_writer.release()
capture.release()
cv2.destroyAllWindows()

Answer 1

OpenCV视频捕获功能不支持Blackmagic设备（可能）。我使用Blackmagic Decklink SDK捕获Blackmagic相机。您可以在Blackmagic支持网站上找到并下载它： Blackmagic design support

请注意，它不支持Python或OpenCV接口，但有C ++跨平台示例，包括Windows MFC。请注意，如果我没记错的话，（颜色）像素格式可能与OpenCV不同：如果你想进行进一步的图像处理，你需要自己转换它们。

Answer 2

我有同样的问题。我解决了它，它使用覆盖libvlc_video_set_callbacks的python-vlc库对帧进行编码，然后使用opencv使用已经以numpy格式转换的帧。

这是代码：

import vlc,cv2
import ctypes
import time
import sys
import numpy as np

from PIL import Image


pl = vlc.MediaPlayer('dshow://')

VIDEOWIDTH = 1280
VIDEOHEIGHT = 720

# size in bytes when RV32
size = VIDEOWIDTH * VIDEOHEIGHT * 4
# allocate buffer
buf1 = (ctypes.c_ubyte * size)()
buf2 = (ctypes.c_ubyte * size)()
# get pointer to buffer
buf_p = ctypes.cast(buf1, ctypes.c_void_p)

# global frame (or actually displayed frame) counter
framenr = 0
test=[]
# vlc.CallbackDecorators.VideoLockCb is incorrect
CorrectVideoLockCb = ctypes.CFUNCTYPE(ctypes.c_void_p, ctypes.c_void_p, ctypes.POINTER(ctypes.c_void_p))

@CorrectVideoLockCb
def _lockcb(opaque, planes):
    print "lock"
    planes[0] = buf_p
    ctypes.memmove(buf2, buf1, size)

    #time.sleep(1)

@vlc.CallbackDecorators.VideoDisplayCb
def _display(opaque, picture):

    global framenr,test

    img = Image.frombuffer("RGBA", (VIDEOWIDTH, VIDEOHEIGHT), buf2, "raw", "BGRA", 0, 1)
    #img.save('img{}.png'.format(framenr))
    #print "display {}".format(framenr)
    # shouldn't do this here! copy buffer fast and process in our own thread, or maybe cycle
    # through a couple of buffers, passing one of them in _lockcb while we read from the other(s).
        #img.save('img{}.png'.format(framenr))
    #img=cv2.cvtColor(np.array(img), cv2.COLOR_BGRA2RGB)
    frame_CV=np.array(img)
    framenr+=1    
    print "frame",framenr,frame_CV.shape        
    test=frame_CV
    font = cv2.FONT_HERSHEY_SIMPLEX    
    cv2.putText(test,"Test",(50,50), font, 0.7,(250,20,30),1,cv2.LINE_AA)
    #cv2.imshow("Test",test)
    #cv2.waitKey(1)
    #if framenr==10:      
        #cv2.imshow("Test",test)        
    #print "OpenCV"

#------------------------------------------------------------------------------    
# MAIN CYCLE
#------------------------------------------------------------------------------
vlc.libvlc_video_set_callbacks(pl, _lockcb, None, _display, None)
pl.video_set_format("RV32", VIDEOWIDTH, VIDEOHEIGHT, VIDEOWIDTH * 4)
pl.play()
#10 seconds are necessary to consolidate memory buffer exchange and library 
#syncronization

time.sleep(10)
while True:


    cv2.imshow("Test",test)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break
pl.stop()
cv2.destroyAllWindows()
#time.sleep(10)
#------------------------------------------------------------------------------

使用BlackMagic卡（强度穿梭机）使用Opencv捕获帧

2 个答案: