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• ffmpeg - using crf and setting a mximum bitrate [closed]

  1er mars 2013, par user1963939

  I am trying to transcode a video to h.264/mp4.
  I am using the crf = 20 but according to the requirements I also want to limit the maximum bitrate to 3mbps.

  I was trying to cheat though it by using x264opts like this

  -x264opts crf=20:vbv-bufsize=14000:vbv-maxrate=3000:keyint=40

  is that the right way to do this ?
  Can this be done or I am stuck with using a contant bitrate and no crf ?

• x264 num_units_in_tick can not be correctly set

  3 mai 2012, par MIKU_LINK_SUCCESS

  When I use x264 lib to encode yuv video stream,I can not set the sps parameter num_units_in_tick(i_num_units_in_tick in struct). I init the x264_param_t as :

      x264_param_t*                     m_x264Param;
  
  
  
      if( x264_param_default_preset( m_x264Param, "superfast", "zerolatency" ) < 0 )
  
      return -1;
  
  
  
     x264_param_apply_fastfirstpass( m_x264Param );
  
  
  
      /* Apply profile restrictions. */
  
      //baseline
  
      if( x264_param_apply_profile( m_x264Param, "baseline" ) < 0 )
  
        return -1;

  The i_rc_method is set to 1. I set the parameters which decide the num_units_in_tick,then call x264_encoder_open to get x264_t .

      m_x264Param->i_timebase_den = 90000;
  
      m_x264Param->i_timebase_num = 3000;
  
      m_x264Param->i_fps_num = 60;
  
      m_x264Param->i_fps_den = 2;

  But, num_units_in_tick is still 1, and time_scale is still 60. How can I set num_units_in_tick to 3000, so one frame occupies 3000 timestamp unit.

• How to stream an webm video through ffmpeg using node.js ?

  4 juillet 2012, par Marcos Lopes

  I have built an node.js server that gets ffmpeg video and pass it to all listeners connected, but the video doesn't play. What i'm doing wrong ?

  Here is my ffmpeg command and output : http://pastebin.com/56BMrx7V

  and in my node.js app :

  var http = require('http');
  
  
  
  var server = http.createServer(function(req, res) {  
  
      if (req.url === '/listen') {  
  
          listen(req, res);  
  
      } else if (req.url === '/publish' && req.method === 'POST') {  
  
          stream(req, res);  
  
      }  
  
  });
  
  
  
  var stream = require('stream');  
  
  var writeStream = new stream.Stream();  
  
  var listeners = [];  
  
  
  
  writeStream.writable = true;  
  
  
  
  writeStream.write = function(data) {  
  
      listeners.forEach(function(listener) {  
  
          listener.write(data);  
  
      });  
  
  };  
  
  
  
  writeStream.end = function() {  
  
      listeners.forEach(function(listener) {  
  
          listener.end();  
  
      });  
  
  };  
  
  
  
  var listen = function(req, res) {  
  
      listeners.push(res);  
  
  
  
      res.writeHead(200, {  
  
          'Date': new Date().toUTCString(),  
  
          'Connection': 'close',  
  
          'Content-Type': 'video/webm',  
  
          'Transfer-Encoding': 'chunked'  
  
      });  
  
  };  
  
  
  
  var stream = function(req, res) {  
  
      req.on('data', function(data) {  
  
          writeStream.write(data);  
  
      });  
  
  
  
      req.on('end', function() {  
  
          writeStream.end();  
  
      });  
  
  }
  
  
  
  server.listen(3000);  
  
  console.log('Listening on localhost port 3000');

  Thanks.