Recherche avancée

Sur d’autres sites (7858)

• ffmpeg produces bad output when called from execve in c++

  31 mai 2016, par Arheisel

  im writing a c++ program that involves ffmpeg being called from a c++ program. a couple of days ago i got it working using std::system

  std::system("ffmpeg -threads auto -y -r 1.74659 -i /mnt/ev_ramdsk/1/%05d-capture.jpg -px_fmt yuv420p -preset ultrafast -r 10 /mnt/ev_ramdsk/1/video.mp4");

  but this only worked once now this produces .mp4 videos of 8MB or so that cannot be played anywhere.. so because of a suggestion in a previous question i moved to execve.

  Here is my code

  child_pid = fork();
  
          if(child_pid < 0){
  
              syslog(LOG_ERR, "ERROR: ffmpeg forking failed");
  
              return false;
  
          }
  
          else if(child_pid > 0){
  
              syslog(LOG_DEBUG, "DEBUG: forking succeeded, pid: %d", child_pid);
  
          }
  
          else if(child_pid == 0){
  
              char *newargv[16];
  
              for(int i=0; i < 15; i++) newargv[i] = (char *)malloc(sizeof(char) * 60); //allocate the array in memory
  
              strcpy(newargv[0], "/usr/bin/ffmpeg");
  
              strcpy(newargv[1], "-threads");
  
              strcpy(newargv[2], "auto");
  
              strcpy(newargv[3], "-y");
  
              strcpy(newargv[4], "-framerate");
  
              tempSS << fps;
  
              strcpy(newargv[5], tempSS.str().c_str());
  
              tempSS.str(std::string());
  
              strcpy(newargv[6], "-i");
  
              strcpy(newargv[7], std::string(conf->dir_ram + dest + "%05d-capture.jpg").c_str());
  
              strcpy(newargv[8], "-pix_fmt");
  
              strcpy(newargv[9], "yuv420p");
  
              strcpy(newargv[10], "-preset");
  
              strcpy(newargv[11], "ultrafast");
  
              strcpy(newargv[12], "-r");
  
              strcpy(newargv[13], "25");
  
              strcpy(newargv[14], std::string(conf->dir_ram + dest + "video.mp4").c_str());
  
              newargv[15] = NULL;
  
  
  
              for(int i=0; i < 15; i++){
  
                  tempSS << "newargv[" << i << "] = \"" << newargv[i] << "\", ";
  
              }
  
              syslog(LOG_DEBUG, "DEBUG:newargv: %s", tempSS.str().c_str());
  
              tempSS.str(std::string());
  
  
  
              char *newenviron[] = { NULL };
  
  
  
              if(execve(newargv[0], newargv, newenviron) == -1){
  
                  syslog(LOG_ERR, "ERROR: execve returned -1");
  
                  exit(EXIT_SUCCESS);
  
              }
  
          }
  
  
  
          wpid = wait(&status);
  
          syslog(LOG_DEBUG, "DEBUG: ffmpeg child terminated, pid: %d, status: %d", wpid, status);

  the output of syslog is :

  May 28 00:25:03 SERVER dt_ev_maker[10471]: DEBUG: forking succeeded, pid: 10658
  
  May 28 00:25:03 SERVER dt_ev_maker[10658]: DEBUG:newargv: 
  
  newargv[0] = "/usr/bin/ffmpeg", 
  
  newargv[1] = "-threads", 
  
  newargv[2] = "auto", 
  
  newargv[3] = "-y", 
  
  newargv[4] = "-framerate", 
  
  newargv[5] = "1.45097", 
  
  newargv[6] = "-i", 
  
  newargv[7] = "/mnt/ev_ramdsk/1/%05d-capture.jpg", 
  
  newargv[8] = "-pix_fmt", 
  
  newargv[9] = "yuv420p", 
  
  newargv[10] = "-preset", 
  
  newargv[11] = "ultrafast", 
  
  newargv[12] = "-r", 
  
  newargv[13] = "25", 
  
  newargv[14] = "/mnt/ev_ramdsk/1/video.mp4",
  
  May 28 00:25:03 SERVER dt_ev_maker[10471]: DEBUG: ffmpeg child terminated, pid: 10658, status: 256

  in this case the video has about 90B size and is also corrupted.

  NOTE : if i run the same command from the command line the video can be played normally.

  what am i doing wrong ?

  Thanks in advance !

  EDIT

  Thanks to ouroborus (changes submitted above) i got it to make 18MB videos, but i cant play them.

• Anomalie #2273 : Choisir la largeur d’affichage des visuels

  27 septembre 2016, par b b

  Voir #3582 et #3449 qui propose d’intégrer le comportement du plugin medoc dans le core, ce qui semble répondre à la demande. Si oui, on pourrait fermer ce ticket et continuer la discussion sur #3582 ?

• Elegant early exit from a spawned ffmpeg process in C

  21 octobre 2016, par jackson80

  I have a program where I build an ffmpeg command string to capture videos with options input through a gtk3 gui. Once I have all my options selected, I spawn a process with the ffmpeg command string. And I add a child watch to tell me when the process has completed.

    // Spawn child process 
  
    ret = g_spawn_async (NULL, argin, NULL, G_SPAWN_DO_NOT_REAP_CHILD, NULL, NULL, &pid1, NULL);
  
    if ( !ret )
  
    {
  
      g_error ("SPAWN FAILED");
  
      return;
  
    }
  
  
  
  /* Add watch function to catch termination of the process.  This function
  
     * will clean any remnants of process */
  
    g_child_watch_add (pid1, (GChildWatchFunc)cb_child_watch, widget );

  Executing ffmpeg from a terminal using a command line, the program will give an option to input a "q" at the terminal to end the ffmpeg process early.
  Is there any way to send a "q" to that spawned process to elegantly end the ffmpeg ? I’m fairly sure I could kill the process using the process id, but I would rather stop it using a mechanism that allows ffmpeg to gracefully exit..
  This is running Centos 7, kernel 4.7.5, ffmpeg version 3.0.2.
  Since I can still access the terminal where the ffmpeg output is displayed, I’ve tried typing a "q", but it has no effect on the process.