代码出处，opencv2 cookbook：
/*------------------------------------------------------------------------------------------*
This file contains material supporting chapter 10 of the cookbook:
Computer Vision Programming using the OpenCV Library.
by Robert Laganiere, Packt Publishing, 2011.
This program is free software; permission is hereby granted to use, copy, modify,
and distribute this source code, or portions thereof, for any purpose, without fee,
subject to the restriction that the copyright notice may not be removed
or altered from any source or altered source distribution.
The software is released on an as-is basis and without any warranties of any kind.
In particular, the software is not guaranteed to be fault-tolerant or free from failure.
The author disclaims all warranties with regard to this software, any use,
and any consequent failure, is purely the responsibility of the user.
Copyright (C) 2010-2011 Robert Laganiere, www.laganiere.name
*------------------------------------------------------------------------------------------*/
#if !defined VPROCESSOR
#define VPROCESSOR
#include <iostream>
#include <iomanip>
#include <sstream>
#include <string>
#include <vector>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <iostream>
#include <opencv2/core/core.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/highgui/highgui.hpp>
#pragma comment(lib,"opencv_core2410d.lib")
#pragma comment(lib,"opencv_highgui2410d.lib")
#pragma comment(lib,"opencv_imgproc2410d.lib")
// The frame processor interface
class FrameProcessor {
public:
// processing method
virtual void process(cv:: Mat &input, cv:: Mat &output)= 0;
};
class VideoProcessor {
private:
// the OpenCV video capture object
cv::VideoCapture capture;
// the callback function to be called
// for the processing of each frame
void (*process)(cv::Mat&, cv::Mat&);
// the pointer to the class implementing
// the FrameProcessor interface
FrameProcessor *frameProcessor;
// a bool to determine if the
// process callback will be called .是否使用回调函数的bool变量
bool callIt;
// Input display window name
std::string windowNameInput;
// Output display window name
std::string windowNameOutput;
// delay between each frame processing
int delay;
// number of processed frames
long fnumber;
// stop at this frame number
long frameToStop;
// to stop the processing
bool stop;
// vector of image filename to be used as input
std::vector<std::string> images;
// image vector iterator
std::vector<std::string>::const_iterator itImg;
// the OpenCV video writer object
cv::VideoWriter writer;
// output filename
std::string outputFile;
// current index for output images
int currentIndex;
// number of digits in output image filename
int digits;
// extension of output images
std::string extension;
// to get the next frame
// could be: video file; camera; vector of images
bool readNextFrame(cv::Mat& frame)
{
if (images.size()==0)
return capture.read(frame);
else {
if (itImg != images.end())
{
frame= cv::imread(*itImg);
itImg++;
return frame.data != 0;
}
}
}
// to write the output frame
// could be: video file or images
void writeNextFrame(cv::Mat& frame)
{
if (extension.length()) { // then we write images
std::stringstream ss;
ss << outputFile << std::setfill('0') << std::setw(digits) << currentIndex++ << extension;
cv::imwrite(ss.str(),frame);
}
else
{ // then write video file
writer.write(frame);
}
}
public:
// Constructor setting the default values
VideoProcessor() : callIt(false), delay(-1),
fnumber(0), stop(false), digits(0), frameToStop(-1),
process(0), frameProcessor(0) {}
// set the name of the video file
bool setInput(std::string filename) {
fnumber= 0;
// In case a resource was already
// associated with the VideoCapture instance
capture.release();
images.clear();
// Open the video file
return capture.open(filename);
}
// set the camera ID
bool setInput(int id)
{
fnumber= 0;
// In case a resource was already
// associated with the VideoCapture instance
capture.release();
images.clear();
// Open the video file
return capture.open(id);
}
// set the vector of input images
bool setInput(const std::vector<std::string>& imgs)
{
fnumber= 0;
// In case a resource was already
// associated with the VideoCapture instance
capture.release();
// the input will be this vector of images
images= imgs;
itImg= images.begin();
return true;
}
// set the output video file
// by default the same parameters than input video will be used
bool setOutput(const std::string &filename, int codec=0, double framerate=0.0, bool isColor=true)
{
outputFile= filename;
extension.clear();
if (framerate==0.0)
framerate= getFrameRate(); // same as input
char c[4];
// use same codec as input
if (codec==0) {
codec= getCodec(c);
}
// Open output video
return writer.open(outputFile, // filename
codec, // codec to be used
framerate, // frame rate of the video
getFrameSize(), // frame size
isColor); // color video?
}
// set the output as a series of image files
// extension must be ".jpg", ".bmp" ...
bool setOutput(const std::string &filename, // filename prefix
const std::string &ext, // image file extension
int numberOfDigits=3, // number of digits
int startIndex=0)
{ // start index
// number of digits must be positive
if (numberOfDigits<0)
return false;
// filenames and their common extension
outputFile= filename;
extension= ext;
// number of digits in the file numbering scheme
digits= numberOfDigits;
// start numbering at this index
currentIndex= startIndex;
return true;
}
// set the callback function that will be called for each frame
void setFrameProcessor(void (*frameProcessingCallback)(cv::Mat&, cv::Mat&))
{
// invalidate frame processor class instance
frameProcessor= 0;
// this is the frame processor function that will be called
process= frameProcessingCallback;
callProcess();
}
// set the instance of the class that implements the FrameProcessor interface
void setFrameProcessor(FrameProcessor* frameProcessorPtr)
{
// invalidate callback function
process= 0;
// this is the frame processor instance that will be called
frameProcessor= frameProcessorPtr;
callProcess();
}
// stop streaming at this frame number
void stopAtFrameNo(long frame)
{
frameToStop= frame;
}
// process callback to be called
void callProcess()
{
callIt= true;
}
// do not call process callback
void dontCallProcess()
{
callIt= false;
}
// to display the processed frames
void displayInput(std::string wn)
{
windowNameInput= wn;
cv::namedWindow(windowNameInput);
}
// to display the processed frames
void displayOutput(std::string wn)
{
windowNameOutput= wn;
cv::namedWindow(windowNameOutput);
}
// do not display the processed frames
void dontDisplay()
{
cv::destroyWindow(windowNameInput);
cv::destroyWindow(windowNameOutput);
windowNameInput.clear();
windowNameOutput.clear();
}
// set a delay between each frame
// 0 means wait at each frame
// negative means no delay
void setDelay(int d)
{
delay= d;
}
// a count is kept of the processed frames
long getNumberOfProcessedFrames()
{
return fnumber;
}
// return the size of the video frame
cv::Size getFrameSize()
{
if (images.size()==0)
{
// get size of from the capture device
int w= static_cast<int>(capture.get(CV_CAP_PROP_FRAME_WIDTH));
int h= static_cast<int>(capture.get(CV_CAP_PROP_FRAME_HEIGHT));
return cv::Size(w,h);
}
else
{ // if input is vector of images
cv::Mat tmp= cv::imread(images[0]);
if (!tmp.data) return cv::Size(0,0);
else return tmp.size();
}
}
// return the frame number of the next frame
long getFrameNumber()
{
if (images.size()==0)
{
// get info of from the capture device
long f= static_cast<long>(capture.get(CV_CAP_PROP_POS_FRAMES));
return f;
} else { // if input is vector of images
return static_cast<long>(itImg-images.begin());
}
}
// return the position in ms
double getPositionMS()
{
// undefined for vector of images
if (images.size()!=0) return 0.0;
double t= capture.get(CV_CAP_PROP_POS_MSEC);
return t;
}
// return the frame rate
double getFrameRate()
{
// undefined for vector of images
if (images.size()!=0) return 0;
double r= capture.get(CV_CAP_PROP_FPS);
return r;
}
// return the number of frames in video
long getTotalFrameCount()
{
// for vector of images
if (images.size()!=0) return images.size();
long t= capture.get(CV_CAP_PROP_FRAME_COUNT);
return t;
}
// get the codec of input video
int getCodec(char codec[4])
{
// undefined for vector of images
if (images.size()!=0) return -1;
union {
int value;
char code[4]; } returned;
returned.value= static_cast<int>(capture.get(CV_CAP_PROP_FOURCC));
codec[0]= returned.code[0];
codec[1]= returned.code[1];
codec[2]= returned.code[2];
codec[3]= returned.code[3];
return returned.value;
}
// go to this frame number
bool setFrameNumber(long pos)
{
// for vector of images
if (images.size()!=0)
{
// move to position in vector
itImg= images.begin() + pos;
// is it a valid position?
if (pos < images.size())
return true;
else
return false;
}
else
{ // if input is a capture device
return capture.set(CV_CAP_PROP_POS_FRAMES, pos);
}
}
// go to this position
bool setPositionMS(double pos)
{
// not defined in vector of images
if (images.size()!=0)
return false;
else
return capture.set(CV_CAP_PROP_POS_MSEC, pos);
}
// go to this position expressed in fraction of total film length
bool setRelativePosition(double pos)
{
// for vector of images
if (images.size()!=0)
{
// move to position in vector
long posI= static_cast<long>(pos*images.size()+0.5);
itImg= images.begin() + posI;
// is it a valid position?
if (posI < images.size())
return true;
else
return false;
}
else
{ // if input is a capture device
return capture.set(CV_CAP_PROP_POS_AVI_RATIO, pos);
}
}
// Stop the processing
void stopIt()
{
stop= true;
}
// Is the process stopped?
bool isStopped()
{
return stop;
}
// Is a capture device opened?
bool isOpened()
{
return capture.isOpened() || !images.empty();
}
// to grab (and process) the frames of the sequence
void run()
{
// current frame
cv::Mat frame;
// output frame
cv::Mat output;
// if no capture device has been set
if (!isOpened())
return;
stop= false;
while (!isStopped())
{
// read next frame if any
if (!readNextFrame(frame))
break;
// display input frame
if (windowNameInput.length()!=0)
cv::imshow(windowNameInput,frame);
// calling the process function or method
if (callIt)
{
// process the frame
if (process)
process(frame, output);
else if (frameProcessor)
frameProcessor->process(frame,output);
// increment frame number
fnumber++;
}
else
{
output= frame;
}
// write output sequence
if (outputFile.length()!=0)
writeNextFrame(output);
// display output frame
if (windowNameOutput.length()!=0)
cv::imshow(windowNameOutput,output);
// introduce a delay
if (delay>=0 && cv::waitKey(delay)>=0)
stopIt();
// check if we should stop
if (frameToStop>=0 && getFrameNumber()==frameToStop)
stopIt();
}
}
};
#endif
/*------------------------------------------------------------------------------------------*
This file contains material supporting chapter 10 of the cookbook:
Computer Vision Programming using the OpenCV Library.
by Robert Laganiere, Packt Publishing, 2011.
This program is free software; permission is hereby granted to use, copy, modify,
and distribute this source code, or portions thereof, for any purpose, without fee,
subject to the restriction that the copyright notice may not be removed
or altered from any source or altered source distribution.
The software is released on an as-is basis and without any warranties of any kind.
In particular, the software is not guaranteed to be fault-tolerant or free from failure.
The author disclaims all warranties with regard to this software, any use,
and any consequent failure, is purely the responsibility of the user.
Copyright (C) 2010-2011 Robert Laganiere, www.laganiere.name
*------------------------------------------------------------------------------------------*/
#include "videoprocessor.h"
void draw(cv::Mat& img, cv::Mat& out)
{
img.copyTo(out);
cv::circle(out, cv::Point(100,100),5,cv::Scalar(255,0,0),2);
}
void canny(cv::Mat& img, cv::Mat& out) {
// Convert to gray
cv::cvtColor(img,out,CV_BGR2GRAY);
// Compute Canny edges
cv::Canny(out,out,100,200);
// Invert the image
cv::threshold(out,out,128,255,cv::THRESH_BINARY_INV);
}
int main()
{
// Open the video file
cv::VideoCapture capture("../bike.avi");
// check if video successfully opened
if (!capture.isOpened())
return 1;
// Get the frame rate
double rate= capture.get(CV_CAP_PROP_FPS);
bool stop(false);
cv::Mat frame; // current video frame
cv::namedWindow("Extracted Frame");
// Delay between each frame
// corresponds to video frame rate
int delay= 1000/rate;
// for all frames in video
while (!stop) {
// read next frame if any
if (!capture.read(frame))
break;
cv::imshow("Extracted Frame",frame);
// introduce a delay
// or press key to stop
if (cv::waitKey(delay)>=0)
stop= true;
}
// Close the video file
capture.release();
cv::waitKey();
// Now using the VideoProcessor class
// Create instance
VideoProcessor processor;
// Open video file
processor.setInput("../bike.avi");
// Declare a window to display the video
processor.displayInput("Input Video");
processor.displayOutput("Output Video");
// Play the video at the original frame rate
processor.setDelay(1000./processor.getFrameRate());
// Set the frame processor callback function
processor.setFrameProcessor(canny);
// Start the process
processor.run();
cv::waitKey();
// Second test
// Create instance
// VideoProcessor processor;
// Open video file
processor.setInput("../bike.avi");
// Get basic info about video file
cv::Size size= processor.getFrameSize();
std::cout << size.width << " " << size.height << std::endl;
std::cout << processor.getFrameRate() << std::endl;
std::cout << processor.getTotalFrameCount() << std::endl;
std::cout << processor.getFrameNumber() << std::endl;
std::cout << processor.getPositionMS() << std::endl;
// No processing
processor.dontCallProcess();
// Output filename
// processor.setOutput("../output/bikeOut",".jpg");
char codec[4];
processor.setOutput("../output/bike.avi",processor.getCodec(codec),processor.getFrameRate());
std::cout << "Codec: " << codec[0] << codec[1] << codec[2] << codec[3] << std::endl;
// Position the stream at frame 300
// processor.setFrameNumber(300);
// processor.stopAtFrameNo(120);
// Declare a window to display the video
processor.displayInput("Current Frame");
processor.displayOutput("Output Frame");
// Play the video at the original frame rate
processor.setDelay(1000./processor.getFrameRate());
// Start the process
processor.run();
std::cout << processor.getFrameNumber() << std::endl;
std::cout << processor.getPositionMS() << std::endl;
cv::waitKey();
}