func: static void opt_new_stream(const char *opt, const char *arg)
  
  {
  
      AVFormatContext *oc;
  
      if (nb_output_files <= 0) {
  
          fprintf(stderr, "At least one output file must be specified\n");
  
          ffmpeg_exit(1);
  
      }
  
      oc = output_files[nb_output_files - 1];
  
  
  
      if      (!strcmp(opt, "newvideo"   )) new_video_stream   (oc);
  
      else if (!strcmp(opt, "newaudio"   )) new_audio_stream   (oc);
  
      else if (!strcmp(opt, "newsubtitle")) new_subtitle_stream(oc);
  
      else assert(0);
  
  }
  