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• burning subtitles onto mp4, such that they always show, and cannot be turned off

  27 janvier 2021, par Plazar99

  I have successfully create a command line that allows subtitles to be displayed, I can see them when I select the track number in VLC. What I would like is to burn the subtitles such that they always show when the mp4 is played by any player, and not provide the option to be turned off. All i need is a clue to pursue. does ffmpeg have an option to do this.
Thanks.

  


• Fragment shader does not show any colour when compiled with vs2013

  11 juin 2015, par 5mayfive

  When compiled with vs2010, the fragment shader works, but when I compiled and run in vs 2013, it’s grey.

  My fragment shader converts the yuv texture into rgb

  Below is my fragment code

      const char *FProgram =
  
      "uniform sampler2D Ytex;\n"
  
      "uniform sampler2D Utex;\n"
  
      "uniform sampler2D Vtex;\n"
  
      "void main(void) {\n"
  
      "  vec4 c = vec4((texture2D(Ytex, gl_TexCoord[0]).r - 16./255.) * 1.164);\n"
  
      "  vec4 U = vec4(texture2D(Utex, gl_TexCoord[0]).r - 128./255.);\n"
  
      "  vec4 V = vec4(texture2D(Vtex, gl_TexCoord[0]).r - 128./255.);\n"
  
      "  c += V * vec4(1.596, -0.813, 0, 0);\n"
  
      "  c += U * vec4(0, -0.392, 2.017, 0);\n"
  
      "  c.a = 1.0;\n"
  
      "  gl_FragColor = c;\n"
  
      "}\n";
  
  
  
  
  
  
  
  
  
  
  
  glClearColor(0, 0, 0, 0);
  
  
  
  PHandle = glCreateProgram();
  
  FSHandle = glCreateShader(GL_FRAGMENT_SHADER);
  
  
  
  
  
  
  
  glShaderSource(FSHandle, 1, &FProgram, NULL);
  
  glCompileShader(FSHandle);
  
  
  
  glAttachShader(PHandle, FSHandle);
  
  glLinkProgram(PHandle);
  
  
  
  
  
  glUseProgram(PHandle);
  
  glDeleteProgram(PHandle);
  
  glDeleteProgram(FSHandle);

  This is my texture code, I receive linesize and yuv frame data from ffmpeg and make into texture. Everything works fine in VS 2010 computer, but when compiled and run in vs2013 computer, it is grey (black n white), no colour

      /* Select texture unit 1 as the active unit and bind the U texture. */
  
  glPixelStorei(GL_UNPACK_ROW_LENGTH, linesize1);
  
  glActiveTexture(GL_TEXTURE1);
  
  i = glGetUniformLocation(PHandle, "Utex");
  
  glUniform1i(i, 1);  /* Bind Utex to texture unit 1 */
  
  glBindTexture(GL_TEXTURE_2D, 1);
  
  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
  
  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
  
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  
  glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, width / 2, height / 2, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, frame1);
  
  glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
  
  
  
  
  
  /* Select texture unit 2 as the active unit and bind the V texture. */
  
  glPixelStorei(GL_UNPACK_ROW_LENGTH, linesize2);
  
  glActiveTexture(GL_TEXTURE2);
  
  i = glGetUniformLocation(PHandle, "Vtex");
  
  glUniform1i(i, 2);  /* Bind Vtext to texture unit 2 */
  
  glBindTexture(GL_TEXTURE_2D, 2);
  
  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
  
  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
  
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  
  glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, width / 2, height / 2, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, frame2);
  
  glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
  
  
  
  
  
  /* Select texture unit 0 as the active unit and bind the Y texture. */
  
  
  
  
  
  
  
  glPixelStorei(GL_UNPACK_ROW_LENGTH, linesize0);
  
  glActiveTexture(GL_TEXTURE0);
  
  i = glGetUniformLocation(PHandle, "Ytex");
  
  glUniform1i(i, 0);
  
  glBindTexture(GL_TEXTURE_2D, 0);
  
  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
  
  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
  
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  
  glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, width, height, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, frame0);
  
  glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
  
  
  
  
  
  
  
  glClear(GL_COLOR_BUFFER_BIT);
  
  
  
  /* Draw image (again and again). */
  
  
  
  glBegin(GL_QUADS);
  
  glTexCoord2i(0, 0);
  
  glVertex2i(-w / 2, h / 2);
  
  glTexCoord2i(1, 0);
  
  glVertex2i(w / 2, h / 2);
  
  glTexCoord2i(1, 1);
  
  glVertex2i(w / 2, -h / 2);
  
  glTexCoord2i(0, 1);
  
  glVertex2i(-w / 2, -h / 2);
  
  glEnd();

  Need guidance here, thanks in advance !

• Record 60 second videos with ffmpeg constantly with webcam (dshow) and show preview

  1er juin 2015, par user1200794

  I’m trying for a while to record a long stream but the recording should be seperated in files with 60 seconds length. Meanwhile, I want to show a video preview.

  Currently I was able to show the preview (with ffmpeg SDL support) and save the files every 60 seconds using multiple output of ffmpeg and a small Java app which is running ffmpeg for 60 seconds and then restart the application with the new file name (timestamp). But than there is a lack of recoding during the restart of around 1 second.

  Is it somehow possible to run a main ffmpeg which is showing the preview and another ffmpeg instance which is doing the recording and can be run with threads (so maybe for 1 second overlapping of the saved streams). I had a look on pipes and streaming but can’t find a suitable solution. I appreciate any idea :)