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• OpenCV and Cloud Cameras

  8 mai 2014, par Alexander

  So as a bit of context ; this program was built originally to work with USB cameras - but a few things changed. I’m trying to convert it to work with networked cameras, but my presence here should make it quite apparent what my level of success has been. I still consider myself somewhat new at programming, and definately new at visual processing/OpenCV - so please forgive a few blunders if I make them. I’m going to try to provide as much detail as possible, so apologies for the length below.

  ---

  I’m using :

  • OpenCV 2.4.6.0
  • Microsoft Visual Studio Express 2012
  • C++
  • D-Link Cloud Camera 7100

  ---

  I am trying to access the DLink camera’s video feed through OpenCV.

  I can access the camera through it’s IP address with a browser without any issues. Unfourtunately ; my program is less cooperative. I’ve put it on two computers (excluding the computer it gets compiled on, which for unrelated/unchangable reasons cannot be placed on the same network the network camera is on) which both fail to grant my program access to the camera. One computer gives the OpenCV-generated error :

  warning : Error opening file (../../modules/highgui/src/cap_ffmpeg_impl.hpp:529)

  This error occurs with just about everything I try that doesn’t somehow generate more problems. The other computer (same code) generates no such error - it just doesn’t get the camera’s output either.

  For reference - the code in OpenCV’s cap_ffmpeg_impl.hpp around line 529 is as follows :

  522    bool CvCapture_FFMPEG::open( const char* _filename )
  
  523    {
  
  524        unsigned i;
  
  525        bool valid = false;
  
  526
  
  527        close();
  
  528
  
  529    #if LIBAVFORMAT_BUILD >= CALC_FFMPEG_VERSION(52, 111, 0)
  
  530        int err = avformat_open_input(&ic, _filename, NULL, NULL);
  
  531    #else
  
  532        int err = av_open_input_file(&ic, _filename, NULL, 0, NULL);
  
  533    #endif
  
  ...
  
  616    }

  ...for which I have no idea what I’m looking at.

  My entire program is rather large, so I’m editing it down as much as possible to help keep this readable - if I miss something you think is important please leave a comment telling me as much so I can throw it in...

  First up - this is one of the first things in main() so I don’t have to recompile every time I want to try a different value :

  3380    cout << "Please Enter Video Location: ";
  
  3381    cin >> videoFeedAddress;
  
  3382    cout << "videoFeedAddress: " << videoFeedAddress << endl;

  Just a simple string value.
  Next up - the actual place we’re having the problem ! Probably...

  Note that in the below code - if networkCam is false and a USB camera is connected there is no problem. The error here is caused by line 153.

  121    void displayCameraView()
  
  122    {
  
  123     if(camviewOn) // displayCameraView is triggered by a button the user can press as often as they want. Doesn't mean we want to let them break everything.
  
  124     {return;}
  
  125     else
  
  126     {
  
  127         CvCapture* cv_cap;
  
  128         VideoCapture cv_cap_IP;
  
  129         Mat color_img_IP;
  
  130         camviewOn = true;
  
  131         int capture;
  
  132         IplImage* color_img;
  
  133         if(!networkCam)
  
  134         {
  
  135             cv_cap = cvCaptureFromCAM(0);
  
  136             Sleep(100);
  
  137             if(!cv_cap)
  
  138             {
  
  139                 setExitError(1002);
  
  140                 if(textOutput){cout << "Video Error: Video input will not work.\n";}
  
  141                 MessageBox(hwnd, "Error opening camera.", "Error", MB_ICONEXCLAMATION);
  
  142                 cvReleaseCapture( &cv_cap );
  
  143                 cvDestroyWindow("Camera View");
  
  144                 return;
  
  145             }
  
  146             color_img = cvQueryFrame(cv_cap);
  
  147             clickPointStorage.create(((Mat)color_img).rows, ((Mat)color_img).cols, CV_8UC3);
  
  148         }
  
  149         else
  
  150         {
  
  151             ///*\
  
  152             
  
  153             cv_cap_IP.open(videoFeedAddress);
  
  154             Sleep(100);
  
  155             if(!cv_cap_IP.isOpened())
  
  156             {
  
  157                 setExitError(1002);
  
  158                 if(textOutput){cout << "Video Error: Video input will not work.\n";}
  
  159                 MessageBox(hwnd, "Error opening camera.", "Error", MB_ICONEXCLAMATION);
  
  160                 cvDestroyWindow("Camera View");
  
  161                 return;
  
  162             }
  
  163             clickPointStorage.create(color_img_IP.rows, color_img_IP.cols, CV_8UC3);
  
  164    
  
  165             //\*/
  
  166         }
  
  167         clickPointStorage.setTo(Scalar(0, 0, 0));
  
  168         cvNamedWindow("Camera View", 0); // create window
  
  169         cvSetMouseCallback("Camera View", CallBackFunc, NULL);
  
  170         IplImage* IplClickPointStorage = new IplImage(clickPointStorage);
  
  171         IplImage* Ipl_IP_Img;
  
  172         
  
  173         if(!networkCam)
  
  174         {
  
  175             for(;;)
  
  176             {
  
  177                 IplClickPointStorage = new IplImage(clickPointStorage);
  
  178                 cvAdd(cvQueryFrame(cv_cap), IplClickPointStorage, color_img); // get frame
  
  181                 cvShowImage("Camera View", color_img); // show frame
  
  182                 capture = cvWaitKey(10); // wait 10 ms or for key stroke
  
  183                 if(capture == 27 || capture == 13 || capture == 32){break;} // if ESC, Return, or space; close window.
  
  184             }
  
  185             /* clean up */
  
  186             cvReleaseCapture( &cv_cap );
  
  187             delete cv_cap;
  
  188             delete IplClickPointStorage;
  
  189         }
  
  190         else
  
  191         {
  
  192             ///*\
  
  193    
  
  194             for(;;)
  
  195             {
  
  196                 cv_cap_IP.read(color_img_IP);
  
  197                 IplClickPointStorage = new IplImage(clickPointStorage);
  
  198                 Ipl_IP_Img = new IplImage(color_img_IP);
  
  199                 cvAdd(Ipl_IP_Img, IplClickPointStorage, color_img);
  
  200                 cvShowImage("Camera View", color_img); // show frame
  
  201                 capture = cvWaitKey(10); // wait 10 ms or for key stroke
  
  202                 if(capture == 27 || capture == 13 || capture == 32){break;} // if ESC, Return, or space; close window.
  
  203             }
  
  204             cv_cap_IP.release();
  
  205             delete Ipl_IP_Img;
  
  206             delete IplClickPointStorage;
  
  207    
  
  208             //\*/
  
  209         }
  
  210         cvDestroyWindow("Camera View");
  
  211         camviewOn = false;
  
  212     }
  
  213     return;
  
  214    }

  As I said, on one computer I get the above error - both of them give me my own error from here :

  155             if(!cv_cap_IP.isOpened())
  
  156             {
  
  157                 setExitError(1002);
  
  158                 if(textOutput){cout << "Video Error: Video input will not work.\n";}
  
  159                 MessageBox(hwnd, "Error opening camera.", "Error", MB_ICONEXCLAMATION);
  
  160                 cvDestroyWindow("Camera View");
  
  161                 return;
  
  162             }

  ...which of course tells me cv_cap_IP is not open. One of my primary concerns is with the videoFeedAddress variable. No value I enter seems to get a different result.

  I searched the Googles - and come across a number of different "possible" answers - but none of them seem to work for me. If you attempt to google it yourself you may come across some of these :

  1. This is one of the first configurations my code was in. No dice.
  2. This one is talking about files - not cameras. It also mentions codecs - but I wouldn’t be able to watch it in a web browser if that were the problem, right ? (Correct me if I’m wrong here...)
  3. This one has the wrong error code/points to the wrong line of code !
  4. This one mentions compiling OpenCV with ffmpeg support - but I believe 2.4.6.0 already comes with that all set and ready ! Otherwise it’s not that different from what I’ve already tried.
  5. Now THIS one appears to be very similar to what I have, but the only proposed solution doesn’t really help as I had already located a list of connections. I do not believe this is a duplicate, because as per THIS meta discussion I had a lot more information and so didn’t feel comfortable taking over someone else’s question - especially if I end up needing to add even more information later.

  Back to the videoFeedAddress variable : I found THIS site that lists a number of possible addresses to connect to it. since there exists no 7100 anywhere in the list - and the install is the same for the DCS-7010L I used the addresses found next to the DCS-7010L listings. Most of them can be reached through the browser, confirming that they reach the camera - but they don’t seem to affect the outcome when I change them.

  As per many of the above links, I’ve tried many of them both with any without username:password, port number (554), and variations on ?.mjpg (the format) at the end.

  Any ideas ?

• Spaces in variable

  13 avril 2012, par Roger

  I am facing some problems with spaces in variables :

  ALBUM=' -metadata album="Peregrinações Alheias"'

  This command :

  ffmpeg -i $R_IMG -r 1 -b 1800 -i $SOUND -acodec libmp3lame -ab 128k "$ALBUM" -y $OUT

  Returns :

  Unable to find a suitable output format for ' -metadata album="Peregrinações Alheias"'

  And if I take out the "" from the variable :

  ffmpeg -i $R_IMG -r 1 -b 1800 -i $SOUND -acodec libmp3lame -ab 128k $ALBUM -y $OUT

  Returns :

  Unable to find a suitable output format for 'Alheias"'

  And I am sure I am missing something in the bash sintax...

  ---

  UPDATE :

  So it looks that the matter is not with spaces but with the "-metadata" argument...

  The problem is that I have many metadata and I'd like to put them in just one variable. Like this :

  META=' -metadata album="Peregrinações" -metadata title="Passeio ao PETAR" -metadata author="Rogério Madureira" -metadata date="2012" -metadata description="Áudio de um passeio ao PETAR" -metadata comment="Áudio capturado com TACAM DR-07MKII e Foto capturada com Canon PowerShot S5IS" '

  And then :

  ffmpeg -i $R_IMG -r 1 -b 1800 -i $SOUND -acodec libmp3lame -ab 128k $META -y $OUT

• FFMPEG Video encoding error

  13 juin 2012, par user1290051

  I am trying to encode my video using ffmpeg. I have taken output of each frame as a separate image and then I'm joining them into a video using ffmpeg. I compiled ffmpeg from source.
  This is the command I used and the errors I keep running into !

  ---:/media/New Volume/temp$ ffmpeg -f image2 -i image%1d.png -vcodec libx264 \
  
  -preset ultrafast -crf 15 output.mp4
  
  ffmpeg version git-2012-03-24-2571506 Copyright (c) 2000-2012 the FFmpeg developers
  
    built on Mar 24 2012 03:47:02 with gcc 4.6.1
  
    configuration: --enable-gpl --enable-libfaac --enable-libmp3lame \
  
      --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora \
  
      --enable-libvorbis --enable-libx264 --enable-nonfree --enable-version3 \
  
      --enable-x11grab
  
    libavutil      51. 44.100 / 51. 44.100
  
    libavcodec     54. 12.100 / 54. 12.100
  
    libavformat    54.  2.100 / 54.  2.100
  
    libavdevice    53.  4.100 / 53.  4.100
  
    libavfilter     2. 65.102 /  2. 65.102
  
    libswscale      2.  1.100 /  2.  1.100
  
    libswresample   0.  7.100 /  0.  7.100
  
    libpostproc    52.  0.100 / 52.  0.100
  
  // ERORRS:: 
  
  [png @ 0xa4d5120] Missing png signature
  
  [image2 @ 0xa4ceb00] decoding for stream 0 failed
  
  [image2 @ 0xa4ceb00] Could not find codec parameters (Video: png)
  
  image%1d.png: could not find codec parameters