Question

我用Jmpg格式的网络摄像头拍摄了一个视频文件。这是我在'mediainfo /path/to/test.flv'下的原始输出

General
Complete name                            : /home/chengtao/git/testopencv/test.flv
Format                                   : AVI
Format/Info                              : Audio Video Interleave
File size                                : 30.0 MiB

Video
ID                                       : 0
Format                                   : JPEG
Codec ID                                 : MJPG
Width                                    : 640 pixels
Height                                   : 480 pixels
Display aspect ratio                     : 4:3
Frame rate                               : 30.000 fps
Color space                              : YUV
Chroma subsampling                       : 4:2:2
Bit depth                                : 8 bits
Compression mode                         : Lossy

Audio
ID                                       : 1
Format                                   : MPEG Audio
Format version                           : Version 1
Format profile                           : Layer 2
Codec ID                                 : 50
Bit rate mode                            : Constant
Bit rate                                 : 160 Kbps
Channel(s)                               : 2 channels
Sampling rate                            : 44.1 KHz
Compression mode                         : Lossy
Alignment                                : Aligned on interleaves

我使用了opencv 3.0示例项目中的代码

import numpy as np
import cv2

cap = cv2.VideoCapture('/home/chengtao/git/testopencv/test.flv')

# take first frame of the video
ret,frame = cap.read()

# setup initial location of window
r,h,c,w = 250,90,400,125  # simply hardcoded the values
track_window = (c,r,w,h)

# set up the ROI for tracking
roi = frame[r:r+h, c:c+w]
hsv_roi =  cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)
mask = cv2.inRange(hsv_roi, np.array((0., 60.,32.)), np.array((180.,255.,255.)))
roi_hist = cv2.calcHist([hsv_roi],[0],mask,[180],[0,180])
cv2.normalize(roi_hist,roi_hist,0,255,cv2.NORM_MINMAX)

# Setup the termination criteria, either 10 iteration or move by atleast 1 pt
term_crit = ( cv2.TERM_CRITERIA_EPS | cv2.TERM_CRITERIA_COUNT, 10, 1 )

while(1):
    ret ,frame = cap.read()

    if ret == True:
        hsv = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)
        dst = cv2.calcBackProject([hsv],[0],roi_hist,[0,180],1)

        # apply meanshift to get the new location
        ret, track_window = cv2.CamShift(dst, track_window, term_crit)

        # Draw it on image
        pts = cv2.boxPoints(ret)
        pts = np.int0(pts)
        img2 = cv2.polylines(frame,[pts],True, 255,2)
        cv2.imshow('img2',img2)

        k = cv2.waitKey(60) & 0xff
        if k == 27:
            break
        else:
            cv2.imwrite(chr(k)+".jpg",img2)

    else:
        break

cv2.destroyAllWindows()
cap.release()

它始终为false，在“ret，frame = cap.read（）”行返回null。有人可以遇到这个问题，有什么建议吗？非常感谢〜

Opencv 3.0处理视频，总是得到空帧

0 个答案: