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• FFmpeg development on Eclipse on Windows

  10 juillet 2013, par Juan Ayala

  The first thing I did was to refer to tutorial on FFmpeg site.

  I set up MSYS+MinGW64, I cloned all the relevant pre-requisites (i.e OpenSSL, x264, rtmpdump),
  I successfully cross-compiled them all. I ran the configure for FFmpeg, and I was able to cross-compile that as well. And my statically linked ffmpeg.exe works to my satisfaction.

  In Eclipse I was able to create a project, load up the source code, navigate it, make some changes, even compile and step-through debug. The problem I am having is with the Eclipse design-time error, and I think this is more of an Eclipse/C++ thing than FFmpeg.

  For example in ffmpeg.c I find this error "Field 'bitstream_filters' could not be resolved" at this line :

  AVBitStreamFilterContext *bsfc = output_streams[i]->bitstream_filters;

  that output_streams is of type

  OutputStream **output_streams

  and when I try to open the declaration for OutputStream Eclipse gives me the option of two locations. Obviously Eclipse is not sure which of these declarations it is, hence the "could not be resolved" error. OutputStream is defined in the following 2 files

  • ffmpeg.h
  • libavformat/smoothstreamingenc.c

  (hmm nice to know FFmpeg can do smooth streaming...) but anyway the correct definition would of been the one in ffmpeg.h.

  So... the whole goal of getting the source into an IDE was so that I could enjoy the benefits of such things like intelisense. What can I do in Eclipse to set some sort of order or rule as to how it should resolve types in cases where the names clash like this ?

• how to explain this C language code from ffmpeg remuxing

  20 avril 2017, par Fidona

  can someone help me what the meaning of this code ? this is a code from ffmpeg remuxing code.

  static void log_packet(const AVFormatContext *fmt_ctx, const AVPacket *pkt, const char *tag, int hours, int mins, int secs, int us, int *time )
  
  {
  
      AVRational *time_base = &fmt_ctx->streams[pkt->stream_index]->time_base;
  
      total = total + pkt->duration;
  
    //  printf( "%d:%d:%d.%d \n", hours,  mins,  secs, us );
  
      *time = av_q2d(*time_base) * pkt->pts ;
  
  }

  I’m kind of new to C language. thank you !

• Opencv mask object from rtsp camera

  19 août 2016, par user3689259

  i want to add an image as mask in camera live frame after detect specific logo .
  if possible Output rtmp ://127.0.0.1:1935/live/mycamOutput ,, I have nginx-rtmp the rtmp can work if we add it in source , pls any one can help me

  //opencv
  
  #include "opencv2/imgcodecs.hpp"
  
  #include "opencv2/imgproc.hpp"
  
  #include "opencv2/videoio.hpp"
  
  #include <opencv2></opencv2>highgui.hpp>
  
  #include <opencv2></opencv2>video.hpp>
  
  //C
  
  #include 
  
  //C++
  
  #include <iostream>
  
  #include <sstream>
  
  
  
  using namespace cv;
  
  using namespace std;
  
  
  
  // Global variables
  
  Mat frame; //current frame
  
  Mat fgMaskMOG2; //fg mask fg mask generated by MOG2 method
  
  Ptr<backgroundsubtractor> pMOG2; //MOG2 Background subtractor
  
  int keyboard; //input from keyboard
  
  
  
  /** Function Headers */
  
  void help();
  
  void processVideo(char* videoFilename);
  
  void processImages(char* firstFrameFilename);
  
  
  
  void help()
  
  {
  
      cout
  
      &lt;&lt; "--------------------------------------------------------------------------" &lt;&lt; endl
  
      &lt;&lt; "This program shows how to use background subtraction methods provided by "  &lt;&lt; endl
  
      &lt;&lt; " OpenCV. You can process both videos (-vid) and images (-img)."             &lt;&lt; endl
  
                                                                                      &lt;&lt; endl
  
      &lt;&lt; "Usage:"                                                                     &lt;&lt; endl
  
      &lt;&lt; "./bg_sub {-vid <video filename="filename">|-img <image filename="filename">}"                     &lt;&lt; endl
  
      &lt;&lt; "for example: ./bg_sub -vid video.avi"                                       &lt;&lt; endl
  
      &lt;&lt; "or: ./bg_sub -img /data/images/1.png"                                       &lt;&lt; endl
  
      &lt;&lt; "--------------------------------------------------------------------------" &lt;&lt; endl
  
      &lt;&lt; endl;
  
  }
  
  
  
  /**
  
   * @function main
  
   */
  
  int main(int argc, char* argv[])
  
  {
  
      //print help information
  
      help();
  
  
  
      //check for the input parameter correctness
  
      if(argc != 3) {
  
          cerr &lt;&lt;"Incorret input list" &lt;&lt; endl;
  
          cerr &lt;&lt;"exiting..." &lt;&lt; endl;
  
          return EXIT_FAILURE;
  
      }
  
  
  
      //create GUI windows
  
      namedWindow("Frame");
  
      namedWindow("FG Mask MOG 2");
  
  
  
      //create Background Subtractor objects
  
      pMOG2 = createBackgroundSubtractorMOG2(); //MOG2 approach
  
  
  
      if(strcmp(argv[1], "-vid") == 0) {
  
          //input data coming from a video
  
          processVideo(argv[2]);
  
      }
  
      else if(strcmp(argv[1], "-img") == 0) {
  
          //input data coming from a sequence of images
  
          processImages(argv[2]);
  
      }
  
      else {
  
          //error in reading input parameters
  
          cerr &lt;&lt;"Please, check the input parameters." &lt;&lt; endl;
  
          cerr &lt;&lt;"Exiting..." &lt;&lt; endl;
  
          return EXIT_FAILURE;
  
      }
  
      //destroy GUI windows
  
      destroyAllWindows();
  
      return EXIT_SUCCESS;
  
  }
  
  
  
  /**
  
   * @function processVideo
  
   */
  
  void processVideo(char* videoFilename) {
  
      //create the capture object
  
      VideoCapture capture(videoFilename);
  
      if(!capture.isOpened()){
  
          //error in opening the video input
  
          cerr &lt;&lt; "Unable to open video file: " &lt;&lt; videoFilename &lt;&lt; endl;
  
          exit(EXIT_FAILURE);
  
      }
  
      //read input data. ESC or 'q' for quitting
  
      while( (char)keyboard != 'q' &amp;&amp; (char)keyboard != 27 ){
  
          //read the current frame
  
          if(!capture.read(frame)) {
  
              cerr &lt;&lt; "Unable to read next frame." &lt;&lt; endl;
  
              cerr &lt;&lt; "Exiting..." &lt;&lt; endl;
  
              exit(EXIT_FAILURE);
  
          }
  
          //update the background model
  
          pMOG2->apply(frame, fgMaskMOG2);
  
          //get the frame number and write it on the current frame
  
          stringstream ss;
  
          rectangle(frame, cv::Point(10, 2), cv::Point(100,20),
  
                    cv::Scalar(255,255,255), -1);
  
          ss &lt;&lt; capture.get(CAP_PROP_POS_FRAMES);
  
          string frameNumberString = ss.str();
  
          putText(frame, frameNumberString.c_str(), cv::Point(15, 15),
  
                  FONT_HERSHEY_SIMPLEX, 0.5 , cv::Scalar(0,0,0));
  
          //show the current frame and the fg masks
  
          imshow("Frame", frame);
  
          imshow("FG Mask MOG 2", fgMaskMOG2);
  
          //get the input from the keyboard
  
          keyboard = waitKey( 30 );
  
      }
  
      //delete capture object
  
      capture.release();
  
  }
  
  
  
  /**
  
   * @function processImages
  
   */
  
  void processImages(char* fistFrameFilename) {
  
      //read the first file of the sequence
  
      frame = imread(fistFrameFilename);
  
      if(frame.empty()){
  
          //error in opening the first image
  
          cerr &lt;&lt; "Unable to open first image frame: " &lt;&lt; fistFrameFilename &lt;&lt; endl;
  
          exit(EXIT_FAILURE);
  
      }
  
      //current image filename
  
      string fn(fistFrameFilename);
  
      //read input data. ESC or 'q' for quitting
  
      while( (char)keyboard != 'q' &amp;&amp; (char)keyboard != 27 ){
  
          //update the background model
  
          pMOG2->apply(frame, fgMaskMOG2);
  
          //get the frame number and write it on the current frame
  
          size_t index = fn.find_last_of("/");
  
          if(index == string::npos) {
  
              index = fn.find_last_of("\\");
  
          }
  
          size_t index2 = fn.find_last_of(".");
  
          string prefix = fn.substr(0,index+1);
  
          string suffix = fn.substr(index2);
  
          string frameNumberString = fn.substr(index+1, index2-index-1);
  
          istringstream iss(frameNumberString);
  
          int frameNumber = 0;
  
          iss >> frameNumber;
  
          rectangle(frame, cv::Point(10, 2), cv::Point(100,20),
  
                    cv::Scalar(255,255,255), -1);
  
          putText(frame, frameNumberString.c_str(), cv::Point(15, 15),
  
                  FONT_HERSHEY_SIMPLEX, 0.5 , cv::Scalar(0,0,0));
  
          //show the current frame and the fg masks
  
          imshow("Frame", frame);
  
          imshow("FG Mask MOG 2", fgMaskMOG2);
  
          //get the input from the keyboard
  
          keyboard = waitKey( 30 );
  
          //search for the next image in the sequence
  
          ostringstream oss;
  
          oss &lt;&lt; (frameNumber + 1);
  
          string nextFrameNumberString = oss.str();
  
          string nextFrameFilename = prefix + nextFrameNumberString + suffix;
  
          //read the next frame
  
          frame = imread(nextFrameFilename);
  
          if(frame.empty()){
  
              //error in opening the next image in the sequence
  
              cerr &lt;&lt; "Unable to open image frame: " &lt;&lt; nextFrameFilename &lt;&lt; endl;
  
              exit(EXIT_FAILURE);
  
          }
  
          //update the path of the current frame
  
          fn.assign(nextFrameFilename);
  
      }
  
  }
  
  </image></video></backgroundsubtractor></sstream></iostream>