Recherche avancée

Sur d’autres sites (14195)

• Returning struct from function causes memory corruption

  8 janvier 2015, par William Seemann

  I’m trying to return a FFmpeg AVDictionary struct from one function to another. I wrote the following two functions :

  int get_p_metadata(State **ps, AVDictionary *metadata) {
  
      printf("get_p_metadata\n");
  
  
  
      State *state = *ps;
  
  
  
      if (!state || !state->pFormatCtx) {
  
          return FAILURE;
  
      }
  
  
  
      metadata = NULL;
  
      av_dict_copy(&metadata, state->pFormatCtx->metadata, 0);
  
  
  
      printf("count in get_p_metadata %d\n", metadata->count);
  
  
  
      return SUCCESS;
  
  }
  
  
  
  int get_metadata(State **ps) {
  
      printf("get_metadata\n");
  
  
  
      AVDictionary m;
  
      get_p_metadata(ps, &m);
  
      printf("count in get_metadata %d\n", (&m)->count);
  
  
  
      return SUCCESS;
  
  }

  The code compiles and runs however when I call the get_metadata function the generated output is :

  count in get_p_metadata 12
  
  count in get_metadata 2073109240

  Can someone explain why the value of count changes from 12 to a random value every time I run this code ? Why isn’t the value of 12 retained once the get_p_metadata function returns ? How would I fix this ?

  UPDATE :

  This solution worked (Thanks to Cornstalks for actually reading the FFmpeg documentation and
  linkdd for the answer) :

  int get_p_metadata (State **ps, AVDictionary **metadata) {
  
      printf("get_p_metadata\n");
  
  
  
      State *state = *ps;
  
  
  
      if (!state || !state->pFormatCtx) {
  
          return FAILURE;
  
      }
  
  
  
      av_dict_copy(metadata, state->pFormatCtx->metadata, 0);
  
  
  
      return SUCCESS;
  
  }
  
  
  
  int get_metadata(State **ps, AVDictionary *metadata) {
  
      printf("get_metadata\n");
  
  
  
      AVDictionary *m = NULL;
  
      get_p_metadata (ps, &m);
  
      printf("count in get_metadata %d\n", m->count);
  
  
  
      return SUCCESS;
  
  }

• Windows 2003 using php popen "start /b" because of executing ffmpeg.exe

  1er juillet 2013, par Oh Seung Kwon

  I have some problem.

  There is a php code that convert audio(wav) to mp3 file with using ffmpeg.exe.

  Here is some code.

  $cmd = "./inc/ffmpeg.exe -i ".$file_name." -acodec mp3 -y -ac 1 -ab 96k ".$mp3_file_name;
  
  
  
  echo $cmd;
  
  echo "Windows";
  
  $handle = popen("start /B ".$cmd, "r");
  
  while(!feof($handle)) {
  
      $read = fread($handle, 2096);
  
      echo $read;
  
  }
  
  pclose($handle);

  Problem is when I execute this code, ffmpeg.exe process isn't terminated. And not gonna die when I stop process with using Windows task manager.

  Do you have a solution for this situation ?

• FFMPEG - Palettegen for animations is not working

  18 juillet 2018, par deanhodges

  I have a script taken from the correct answer at https://superuser.com/questions/1002562/convert-multiple-images-to-a-gif-with-cross-dissolve, but I am getting no results.

  Even copying the code word for word does not work for me.

  However, if I run $ffmpeg = shell_exec("ffmpeg -i images/image001.jpg -vf palettegen palette_test.png"); on a single image, it works fine. But because I need it for an animation, I need to create a pallete for all images.

  Unless of course, on each image in the GIF sequence I can load a new palette ?

  $q = "ffmpeg -f image2 -framerate 0.5 -i ../view/client/files/".$dir."/%*.jpg -i palettePro.png -lavfi paletteuse -y .." . $save_path . '/' . $filename . " -report";