使用OpenCV采集摄像头的视频并保存为文件

OpenCV的VideoCapture功能强大，它封装了各种不同的API，见videoio.hpp

enum VideoCaptureAPIs {
       CAP_ANY          = 0,            //!< Auto detect == 0
       CAP_VFW          = 200,          //!< Video For Windows (platform native)
       CAP_V4L          = 200,          //!< V4L/V4L2 capturing support via libv4l
       CAP_V4L2         = CAP_V4L,      //!< Same as CAP_V4L
       CAP_FIREWIRE     = 300,          //!< IEEE 1394 drivers
       CAP_FIREWARE     = CAP_FIREWIRE, //!< Same as CAP_FIREWIRE
       CAP_IEEE1394     = CAP_FIREWIRE, //!< Same as CAP_FIREWIRE
       CAP_DC1394       = CAP_FIREWIRE, //!< Same as CAP_FIREWIRE
       CAP_CMU1394      = CAP_FIREWIRE, //!< Same as CAP_FIREWIRE
       CAP_QT           = 500,          //!< QuickTime
       CAP_UNICAP       = 600,          //!< Unicap drivers
       CAP_DSHOW        = 700,          //!< DirectShow (via videoInput)
       CAP_PVAPI        = 800,          //!< PvAPI, Prosilica GigE SDK
       CAP_OPENNI       = 900,          //!< OpenNI (for Kinect)
       CAP_OPENNI_ASUS  = 910,          //!< OpenNI (for Asus Xtion)
       CAP_ANDROID      = 1000,         //!< Android - not used
       CAP_XIAPI        = 1100,         //!< XIMEA Camera API
       CAP_AVFOUNDATION = 1200,         //!< AVFoundation framework for iOS (OS X Lion will have the same API)
       CAP_GIGANETIX    = 1300,         //!< Smartek Giganetix GigEVisionSDK
       CAP_MSMF         = 1400,         //!< Microsoft Media Foundation (via videoInput)
       CAP_WINRT        = 1410,         //!< Microsoft Windows Runtime using Media Foundation
       CAP_INTELPERC    = 1500,         //!< Intel Perceptual Computing SDK
       CAP_OPENNI2      = 1600,         //!< OpenNI2 (for Kinect)
       CAP_OPENNI2_ASUS = 1610,         //!< OpenNI2 (for Asus Xtion and Occipital Structure sensors)
       CAP_GPHOTO2      = 1700,         //!< gPhoto2 connection
       CAP_GSTREAMER    = 1800,         //!< GStreamer
       CAP_FFMPEG       = 1900,         //!< Open and record video file or stream using the FFMPEG library
       CAP_IMAGES       = 2000,         //!< OpenCV Image Sequence (e.g. img_%02d.jpg)
       CAP_ARAVIS       = 2100,         //!< Aravis SDK
       CAP_OPENCV_MJPEG = 2200,         //!< Built-in OpenCV MotionJPEG codec
       CAP_INTEL_MFX    = 2300          //!< Intel MediaSDK
     };

VideoCapture不仅可以采集摄像头的视频，还可以采集rtsp流，rtmp流。

现在把代码放上来，这个代码是对摄像头的视频进行采集，并保存为文件。

#include 
#include 
#include 
#include 

using namespace std;
using namespace cv;

int main()
{
	VideoCapture cap(0);
	if (!cap.isOpened())
	{
		printf("open video capture failed!\n");
		return 1;
	}

	Mat Frame;

	//设置保存的视频帧数目
	int frameNum = 200;

	//保存视频的路径
	string outputVideoPath = "test.avi";

	//获取当前摄像头的视频信息
	cv::Size sWH = cv::Size((int)cap.get(CV_CAP_PROP_FRAME_WIDTH), (int)cap.get(CV_CAP_PROP_FRAME_HEIGHT));

	VideoWriter outputVideo;
	outputVideo.open(outputVideoPath, CV_FOURCC('M', 'P', '4', '2'), 25.0, sWH);

	while (cap.isOpened() && frameNum > 0)
	{
		cap >> Frame;

		if (Frame.empty()) break;

		outputVideo << Frame;

		frameNum--;

		imshow("img", Frame);

		char c = (char)waitKey(10);
		if (c == 'q') break;
	}

	outputVideo.release();

	system("pause");
}