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• Terminal text becomes invisible after terminating subprocess

  21 novembre 2016, par wim

  After terminating an ffmpeg subprocess, the terminal gets messed up - typed characters are invisible ! The input still works in that commands can be executed, but keyboard input is not echoed to the terminal.

  Issuing shell command reset puts everything back to normal (or !reset from within ipython), so a workaround the issue is calling os.system('reset') inside the script.

  Other things I’ve tried : import curses; curses.initscr() before spawning the subprocess and curses.endwin() after termination, which worked somewhat but broke other stuff. Another possibly related issue is that after spawning the child process, the interactive terminal becomes laggy and sometimes fails to capture typed characters.

  The code to spawn the process looks like :

  with open('/tmp/stdout.log', 'w') as o:
  
      with open('/tmp/stderr.log', 'w') as e:
  
          proc = subprocess.Popen([args], stdout=o, stderr=e)

  And later to stop it :

  proc.terminate()
  
  proc.communicate()

  What could be going wrong here ?

• Nodejs youtube-dl ffmpeg audio stream

  19 septembre 2015, par Majster

  I have an issue with streaming video from YouTube. I have a http server which attempts to grab the raw video url, pull out the audio, convert it to mp3 and stream it to clients. The issue is that I’m not getting any audio on my client. Code is below (it’s all work in progress so there’s a lot of hardcoded stuff in there).

  // The obvious stuff
  
  var exec = require('child_process').exec;
  
  var spawn = require('child_process').spawn;
  
  var request = require('request');
  
  var http = require('http');
  
  
  
  //Listen for requests
  
  var server = http.createServer(function(req, response) {
  
     //This command runs youtube-dl and gets the video url
  
     var command = './node_modules/youtube-dl/bin/youtube-dl --simulate --get-url http://www.youtube.com/watch?v=5qF_qbaWt3Q';
  
     var exc = exec(command, function(error, stdout, stderr) {
  
        var downloadUrl = stdout.toString(); //Convert the buffer to string
  
        downloadUrl = downloadUrl.substring(0, downloadUrl.length - 1); //And strip the '\n' sign at the end
  
        console.log("This thing is: '" + downloadUrl + "'");
  
        response.writeHead(200, {
  
           'Content-Type': 'audio/mpeg'
  
        }); //When this is mpeg3 browser will download a blank .mp3 file now it tries to stream it
  
  
  
        //Spawn the ffmpeg child process
  
        var child = spawn('ffmpeg', ['-i', 'pipe:0', '-acodec', 'libmp3lame','-f', 'mp3', '-']);
  
        child.stdout.pipe(response); //Pipe it so it writes to our response
  
  
  
        // fs.createReadStream(filePath).pipe(child.stdin); - this is a testing thing ---> fs is filesystem and filePath is a link to a file - works
  
        request({url: downloadUrl, headers: {'Youtubedl-no-compression': 'True'}}).pipe(child.stdin); //Request the data and pipe it to ffmpeg for processing
  
     });
  
  });

  I can provide any additional info if needed. But the thing works if I try to use a file instead of request call so there is no problem with ffmpeg and other settings. Is it possible that YouTube has a protection against downloading videos this way ? I tried to paste the URL of console.log into my browser and nothing happens - no video. How can I fix this ?

• avformat_open_input failed to open unnamed pipe

  8 octobre 2015, par user2406774

  hi i am writing an application that reads data from network and feeds it to unnamed pipe and i want to read it from other end of pipe using avformat_open_input but this call blocking infinetly any idea about how to read stream from unnamed pipe

  here is the flow of code

   int fd[2]
  
      pipe(fd);
  
      if(fork()==0){
  
      //child process
  
      close(fd[1]);
  
      avcodec_register_all();
  
      av_register_all();
  
      avformat_network_init();
  
  
  
      AVInputFormat *input_format = av_find_input_format("mp4");
  
      if (!input_format)
  
      {
  
      fprintf(stderr, "Could not find MP4 demuxer.\n");
  
      exit(1);
  
      }
  
  
  
      AVFormatContext *input_context = NULL;
  
      fprintf(stderr,"Before opening input context\n");
  
      int ret = avformat_open_input(&input_context, fd[0],input_format, NULL);
  
     // int ret = avformat_open_input(&input_context, "pipe:fd[0]",input_format, NULL);
  
      fprintf(stderr,"After opening input context\n");
  
  
  
      }
  
  
  
  
  
      else{
  
          //parent process
  
          close(fd[0]);
  
          read data from Network();
  
          //write it to pipe
  
          ret=write(fd[1], udp_packet, len);
  
  
  
          }

  after opening input stream i am trying to transcode the mp4 to mpeg ts file .if i give mp4 file as filename filed in avformat_open_input API it is working fine

  any suggestions ?