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• Render FFmpeg AVFrame as OpenGL texture ?

  5 mars 2019, par ZeroDefect

  I’m attempting to to render a jpeg image (1024x1024 pixels) in the form of an FFmpeg AVFrame as a texture in OpenGL. What I get instead is something that appears as a 1024x1024 dark green quad :

  

  The code to render the AVFrame data in OpenGL is shown below. I have convinced myself that the raw RGB data held within the FFmpeg AVFrame data is not solely dark green.

  GLuint g_texture = {};
  
  
  
  //////////////////////////////////////////////////////////////////////////
  
  void display()
  
  {
  
      // Clear color and depth buffers
  
      glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  
      glMatrixMode(GL_MODELVIEW);     // Operate on model-view matrix
  
  
  
      glEnable(GL_TEXTURE_2D);
  
      GLuint texture = g_texture;
  
      glBindTexture(GL_TEXTURE_2D, texture);
  
  
  
      // Draw a quad
  
      glBegin(GL_QUADS);
  
      glVertex2i(0, 0); // top left
  
      glVertex2i(1024, 0); // top right
  
      glVertex2i(1024, 1024); // bottom right
  
      glVertex2i(0, 1024); // bottom left
  
      glEnd();
  
  
  
      glDisable(GL_TEXTURE_2D);
  
      glBindTexture(GL_TEXTURE_2D, 0);
  
  
  
      glFlush();
  
  }
  
  
  
  /* Initialize OpenGL Graphics */
  
  void initGL(int w, int h)
  
  {
  
      glViewport(0, 0, w, h); // use a screen size of WIDTH x HEIGHT
  
      glEnable(GL_TEXTURE_2D);     // Enable 2D texturing
  
  
  
      glMatrixMode(GL_PROJECTION);     // Make a simple 2D projection on the entire window
  
      glOrtho(0.0, w, h, 0.0, 0.0, 100.0);
  
      glMatrixMode(GL_MODELVIEW);    // Set the matrix mode to object modeling
  
      //glTranslatef( 0, 0, -15 );
  
  
  
      glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
  
      glClearDepth(0.0f);
  
      glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear the window
  
  }
  
  
  
  //////////////////////////////////////////////////////////////////////////
  
  int main(int argc, char *argv[])
  
  {
  
      std::shared_ptr<avframe> apAVFrame;
  
      if (!load_image_to_AVFrame(apAVFrame, "marble.jpg"))
  
      {
  
          assert(false);
  
          return 1;
  
      }
  
  
  
      // From here on out, the AVFrame is RGB interleaved
  
      // and is sized to 1,024 x 1,024 (power of 2).
  
  
  
      glutInit(&amp;argc, argv);
  
      glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
  
      glutInitWindowSize(1060, 1060);
  
      glutInitWindowPosition(0, 0);
  
      glutCreateWindow("OpenGL - Creating a texture");
  
  
  
      glGenTextures(1, &amp;g_texture);
  
  
  
      //glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
  
      glBindTexture(GL_TEXTURE_2D, g_texture);
  
      glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, apAVFrame->width,
  
                   apAVFrame->height, 0, GL_RGB, GL_UNSIGNED_BYTE,
  
                   apAVFrame->data[0]);
  
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); /* We will use linear interpolation for magnification filter */
  
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); /* We will use linear interpolation for minifying filter */
  
  
  
      initGL(1060, 1060);
  
  
  
      glutDisplayFunc(display);
  
  
  
      glutMainLoop();
  
  
  
      return 0;
  
  }
  
  </avframe>

  Environment :

  • Ubuntu 18.04
  • GCC v8.2

  EDIT : As per @immibis’ suggestion below, it all works when I change the rendering of the quad to :

  // Draw a quad
  
  glBegin(GL_QUADS);
  
  glTexCoord2f(0, 0);
  
  glVertex2i(0, 0); // top left
  
  glTexCoord2f(1, 0);
  
  glVertex2i(1024, 0); // top right
  
  glTexCoord2f(1, 1);
  
  glVertex2i(1024, 1024); // bottom right
  
  glTexCoord2f(0, 1);
  
  glVertex2i(0, 1024); // bottom left
  
  glEnd();

• Detecting missing audio in MOV files

  27 décembre 2013, par user1479359

  i'm curious if there is a way to detect if audio is missing or broken from a MOV video file. Recently there was a MOV file which was playable, but the audio was "missing".

  I tried ffmpeg to get specific errors but it did not give me any. I only noticed that the audio bitrate was very low, 2kb/s. Apart from checking the audio bitrate is there a way to detect such broken video clips with ffmpeg ?

  The mising audio could have been caused by an unsuccessful copying of the file.

• How do dcraw and stdin work together ?

  25 juillet 2018, par Metin Akkın

  I want to use this :

  dcraw -a -q 3 -6 -v -I < a.nef

  but the picture becomes a dark image. I changed draw.c library but it doesnt work. I want to use stdin and I use this link : https://blog.mclemon.io/dcraw-and-stdin. Please help me.