Question

用OpenCV写入AVI视频出现错误，《学习OpenCV》里的例2-10

#include"cv.h"
#include"highgui.h"
int main(int argc,char* argv[])
{
CvCapture* capture=0;
capture=cvCreateFileCapture(argv[1]);
if(!capture){return -1;}
IplImage *bgr_frame=cvQueryFrame(capture);
double fps=cvGetCaptureProperty(capture,CV_CAP_PROP_FPS);
CvSize size=cvSize(
(int)cvGetCaptureProperty(capture,CV_CAP_PROP_FRAME_WIDTH),
(int)cvGetCaptureProperty(capture,CV_CAP_PROP_FRAME_HEIGHT)
);
CvVideoWriter *writer=cvCreateVideoWriter(
argv[2],CV_FOURCC('M','J','P','G'),fps,size
);
IplImage *logpolar_frame=cvCreateImage(size,IPL_DEPTH_8U,3);
while((bgr_frame=cvQueryFrame(capture))!=NULL)
{
cvLogPolar(
bgr_frame,
logpolar_frame,
cvPoint2D32f(bgr_frame->width/2,bgr_frame->height/2),
40,CV_INTER_LINEAR+CV_WARP_FILL_OUTLIERS);
cvWriteFrame(writer,logpolar_frame);
}
cvReleaseVideoWriter(&writer);
cvReleaseImage(&logpolar_frame);
cvReleaseCapture(&capture);
return 0;
}

Answer 1

别听他们胡说，把这句
CvVideoWriter *writer=cvCreateVideoWriter(
argv[2],CV_FOURCC('M','J','P','G'),fps,size
);
改成这句就可以了
CvVideoWriter *writer=cvCreateVideoWriter(argv[2],-1,fps,size);

Answer 2

你是什么系统，opencv哪个版本的啊？
应该是ffmpeg包没安装吧~

Answer 3

你的是win7吧，学习openCV上使用读取摄像头的方法不适合这个操作系统了，建议用xp。