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• Ip camera using ffmpeg drawing on screen

  6 mars 2014, par user3177342

  I'm using ffmpeg 1.2 to take video from ip camera.I make it draw on the screen, so I wonder if there is some event mechanism to to know if it is time to call av_read_frame ?
  If I read frame not so frequent as the camera gives frames i get segmentation fault = on some malloc functions inside ffmpeg routines(video_get_buffer)

  I also get segmentation fault just when drawing on screen.

  In Render function call every 0 miliseconds

  void BasicGLPane::DrawNextFrame()
  
  {
  
  int f=1;
  
  while(av_read_frame(pFormatCtx, &packet)>=0)
  
      {
  
          // Is this a packet from the video stream?
  
          if(packet.stream_index==videoStream)
  
          {
  
  
  
  
  
              // Decode video frame
  
              avcodec_decode_video2(pCodecCtx, pFrame, &FrameFinished,
  
                                    &packet);
  
  
  
              // Did we get a video frame?
  
              if(FrameFinished)
  
              {
  
                  f++;
  
                  this->fram->Clear();
  
                 // if (pFrame->pict_type == AV_PICTURE_TYPE_I) wxMessageBox("I cadr");
  
                  if (pFrame->pict_type != AV_PICTURE_TYPE_I)
  
                  printMVMatrix(f, pFrame, pCodecCtx);
  
                  pFrameRGB->linesize[0]= pCodecCtx->width*3; // in case of rgb4  one plane
  
  
  
                  sws_scale(swsContext, pFrame->data, pFrame->linesize, 0, pCodecCtx->height, pFrameRGB->data, pFrameRGB->linesize);
  
                  //glGenTextures(1, &VideoTexture);
  
                  if ((*current_Vtex)==VideoTexture) current_Vtex = &VideoTexture2;else current_Vtex = &VideoTexture;
  
                  glBindTexture(GL_TEXTURE_2D, (*current_Vtex));
  
                  glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
  
                  glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
  
                  glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
  
                  glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, pCodecCtx->width, pCodecCtx->height, GL_RGB, GL_UNSIGNED_BYTE, pFrameRGB->data[0]);
  
                  //glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, pCodecCtx->width, pCodecCtx->height, 0, GL_RGB, GL_UNSIGNED_BYTE, pFrameRGB->data[0]);
  
                  //glDeleteTextures(1, &VideoTexture);
  
                  GLenum err;
  
                  while ((err = glGetError()) != GL_NO_ERROR)
  
                  {
  
                      cerr << "OpenGL error: " << err << endl;
  
                  }
  
                //  av_free(buffer);
  
              }
  
          }
  
  
  
          // Free the packet that was allocated by av_read_frame
  
          av_free_packet(&packet);
  
          if (f>1) break;
  
      }
  
  
  
  //av_free(pFrameRGB);
  
  }

  The picture I get on the screen is strange (green quads and red lines are motion vectors of those quads)

  http://i.stack.imgur.com/9HJ9t.png

• Inconsistant rendering in libmelt XML and C interface and 'hold' producer and avformat consumer

  14 octobre 2016, par Leif Andersen

  I am trying to create a short video that is just a single image. (I know its a bit silly, but its a test for something bigger).

  The code I have for rendering it is :

  #include <framework></framework>mlt.h>
  
  #include 
  
  #include 
  
  
  
  int main() {
  
    if(mlt_factory_init(NULL)) {
  
      mlt_profile p = mlt_profile_init(NULL);
  
      mlt_consumer target = mlt_factory_consumer(p, "avformat", 
  
      mlt_producer source = mlt_factory_producer(p, "hold", "/Users/leif/logo.png");
  
      mlt_producer_set_in_and_out(source, 0, 10);
  
      mlt_consumer_connect(target, mlt_producer_service(source));
  
      mlt_consumer_start(target);
  
  
  
      sleep(5);
  
      mlt_consumer_stop(target);
  
  
  
      mlt_consumer_close(target);
  
      mlt_producer_close(source);
  
      mlt_factory_close();
  
    } else {
  
      printf("No\n");
  
    }
  
  
  
    return 0;
  
  }

  Where logo.png is this file.

  When I run this code and play output.mp4, the picture comes out all garbelled. There is a green line in the middle and the logo is superimposed on itself a lot.

  On the other hand, if I change the consumer to be SDL, the image plays just fine.

  And finally, if I change the consumer to be XML, and then use the melt command line application to render it :

  melt -consumer avformat:xmlout.mp4 output.xml

  and play the video, it also plays fine.

  Is there something I am missing in the avformat consumer that I should be setting ? Or something else that I am missing here ?

  Edit : For reference, the outputted xml file : output.xml is :

  <?xml version="1.0" encoding="utf-8"?>
  
  <mlt version="6.2.0" root="/Users/leif/src/video/private" title="Anonymous Submission" parent="producer0" in="0" out="10">
  
        <profile description="DV/DVD PAL" width="720" height="576" progressive="0" colorspace="601"></profile>
  
    <producer title="Anonymous Submission" in="0" out="10">
  
      <property>15000</property>
  
      <property>pause</property>
  
      <property>/Users/leif/logo.png</property>
  
      <property>1.06667</property>
  
      <property>0</property>
  
      <property>onefield</property>
  
      <property>hold</property>
  
      <property>1</property>
  
    </producer>
  
  </mlt>

• Inconsistant rendering in mlt XML and C interface and 'hold' producer and avformat consumer

  14 octobre 2016, par Leif Andersen

  I am trying to create a short video that is just a single image. (I know its a bit silly, but its a test for something bigger).

  The code I have for rendering it is :

  #include <framework></framework>mlt.h>
  
  #include 
  
  #include 
  
  
  
  int main() {
  
    if(mlt_factory_init(NULL)) {
  
      mlt_profile p = mlt_profile_init(NULL);
  
      mlt_consumer target = mlt_factory_consumer(p, "avformat", 
  
      mlt_producer source = mlt_factory_producer(p, "hold", "/Users/leif/logo.png");
  
      mlt_producer_set_in_and_out(source, 0, 10);
  
      mlt_consumer_connect(target, mlt_producer_service(source));
  
      mlt_consumer_start(target);
  
  
  
      sleep(5);
  
      mlt_consumer_stop(target);
  
  
  
      mlt_consumer_close(target);
  
      mlt_producer_close(source);
  
      mlt_factory_close();
  
    } else {
  
      printf("No\n");
  
    }
  
  
  
    return 0;
  
  }

  Where logo.png is this file.

  When I run this code and play output.mp4, the picture comes out all garbelled. There is a green line in the middle and the logo is superimposed on itself a lot.

  On the other hand, if I change the consumer to be SDL, the image plays just fine.

  And finally, if I change the consumer to be XML, and then use the melt command line application to render it :

  melt -consumer avformat:xmlout.mp4 output.xml

  and play the video, it also plays fine.

  Is there something I am missing in the avformat consumer that I should be setting ? Or something else that I am missing here ?

  Edit : For reference, the outputted xml file : output.xml is :

  <?xml version="1.0" encoding="utf-8"?>
  
  <mlt version="6.2.0" root="/Users/leif/src/video/private" title="Anonymous Submission" parent="producer0" in="0" out="10">
  
        <profile description="DV/DVD PAL" width="720" height="576" progressive="0" colorspace="601"></profile>
  
    <producer title="Anonymous Submission" in="0" out="10">
  
      <property>15000</property>
  
      <property>pause</property>
  
      <property>/Users/leif/logo.png</property>
  
      <property>1.06667</property>
  
      <property>0</property>
  
      <property>onefield</property>
  
      <property>hold</property>
  
      <property>1</property>
  
    </producer>
  
  </mlt>