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• Gracefully closing FFMPEG child processes from node

  10 juin 2019, par Gordon

  I am trying to record numerous audio feeds using ffmpeg. Node downloads a config file with the stream URLS (HLS M3U8 playlists), parses it and starts the appropriate number of ffmpeg instances. When I go to shut them down, nothing happens and I have to kill them with task manager, resulting in corrupt files. When I am debugging and hit control-c within a minute or two of starting the program, it works without issue. When I need to record more than 5-10 minutes that I have problems.

  I found this related question from 2013, and adapted it to fit my multiple stream situation.

  The recorder processes are started with the following code (inside the http request callback) :

  config.audio_config.forEach((channel,i)=>{
  
  self.liveChannels++;
  
  
  
  console.log(`   ${channel.number}`);
  
  self.Channels[i] = spawn('ffmpeg', ['-i', `${channel.base_url + channel.stream_ios}`,  '-c:v', 'none', '-c:a', 'copy', `Output\\${config.folder}\\${channel.number}.m4a`]);
  
  self.Channels[i].stdin.setEncoding('utf8');
  
  self.Channels[i].chNum = channel.number;
  
  
  
  self.Channels[i].on('exit',(code,sig)=>{
  
  console.log(`   Channel ${channel.number} recorder closed.`);
  
  self.liveChannels--;
  
  if(self.liveChannels === 0){
  
      process.exit();
  
  }
  
  });
  
  });
  
  console.log('Press Ctl-C to start Shutdown');

  My shutdown function (triggered by SIGINT to main process) is :

  function shutdown() {
  
      self.Channels.forEach((chan)=>{
  
          chan.stdin.write('q');
  
          chan.stdin.end(); //I have tried both with and without this line and chan.stdin.end('q')
  
      });
  
  
  
  }

  UPDATE :
  Switching to an AAC container file (simply changed the extension on the output) removed the need for a graceful FFMPEG exit. I still would like to know why sending ’q’ to stdin only kills the FFMPEG process for the first 10 minutes.

• ffplay does not exit in forked child

  6 septembre 2019, par user12030145

  ffplay  -autoexit does not exit in a forked child

  I need to pipe my application (stdout) to ffplay (stdin). I do this by forking ffplay as a child and using -i pipe:0 as argument.

  #include 
  
  #include 
  
  #include <sys></sys>types.h>
  
  #include <sys></sys>wait.h>
  
  
  
  int main(int argc, const char** argv)
  
  {
  
  int tube[2];
  
  int c;
  
  FILE* f = fopen(argv[1], "rb");
  
  pid_t pid;
  
  if (argc &lt; 2) return -1;
  
  if (pipe(tube))  {
  
      perror("Pipe");
  
      return -1;
  
    }
  
  
  
  // main process cats a .mlp file to stdout, sent to a child ffplay stdin through a pipe
  
  char* const arg[] = {"-i", "pipe:0", "-f", "mlp", "-nodisp", "-autoexit", NULL};
  
  switch (pid = fork())    {
  
              case -1:
  
                  fprintf(stderr,"%s\n", "Could not launch ffplay");
  
                  break;
  
  
  
              case 0:
  
                  close(tube[1]);
  
                  dup2(tube[0], STDIN_FILENO);
  
                  execv("/usr/bin/ffplay", arg);
  
                  fprintf(stderr, "%s\n", "Runtime failure in ffplay child process");
  
                  return -2;
  
  
  
              default:
  
                  close(tube[0]);
  
                  dup2(tube[1], STDOUT_FILENO);
  
          }
  
  
  
  // Here the main process code sending the .mlp file to stdout...
  
  
  
  while ((c = fgetc(f)) != EOF) putchar(c);
  
  
  
  waitpid(pid, NULL, 0);
  
  fclose(f);
  
  
  
  // main never returns
  
  return 0;
  
  }

  The issue is that in this context, ffplay -autoexit never exits (GNU-Linux platform). In a main process, ffplay -autoexit always exits at the end of a media file.
  Is there a pure C workaround without using system, popen or scripting ?
  Is this a feature or a bug of ffplay (I cannot tell) ?

• avformat/hlsenc : Fix leak of child AVFormatContext

  16 décembre 2019, par Andreas Rheinhardt

  avformat/hlsenc : Fix leak of child AVFormatContext
  Before ed897633, the hls muxer would free its child AVFormatContexts
  
  and reset the pointer to these contexts to NULL immediately afterwards ;
  
  ed897633 moved the former to later (into a separate function), but kept
  
  the resetting, ensuring that the child context leaks.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  
  Reviewed-by : Steven Liu <lq@onvideo.cn>
  

  • [DH] libavformat/hlsenc.c