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• Streaming video written using FFmpeg (C# using AutoGen) sends multiple data requests

  26 juin 2016, par williamtroup

  I’ve written a video generator that rights a video in h264 format (mp4). When I stream the video from my azure service, i’m seeing the following network traffic :

  

  The AVCodecContext layout I’m using is as follows :

  AVCodec* videoCodec = ffmpeg.avcodec_find_encoder(AVCodecID.AV_CODEC_ID_H264)
  
  AVCodecContext* videoCodecContext = ffmpeg.avcodec_alloc_context3(videoCodec);
  
  videoCodecContext->bit_rate = 400000;
  
  videoCodecContext->width = 1280;
  
  videoCodecContext->height = 720;
  
  videoCodecContext->gop_size = 12;
  
  videoCodecContext->max_b_frames = 1;
  
  videoCodecContext->pix_fmt = videoCodec->pix_fmts[0];
  
  videoCodecContext->codec_id = videoCodec->id;
  
  videoCodecContext->codec_type = videoCodec->type;
  
  videoCodecContext->time_base = new AVRational
  
  {
  
      num = 1,
  
      den = 30
  
  };
  
  
  
  ffmpeg.av_opt_set(videoCodecContext->priv_data, "preset", "ultrafast");

  I cannot figure out how to solve this problem. Videos generating using Windows Movie Maker stream perfectly.

  Also, this appears to only happening in Google Chrome.

• how can i stop ffmpeg when no new frame come to /dev/video0

  17 mai 2022, par itirou tarou

  I am now modifying stream from camera with our program(programA) and output as .ts files like below.

  


  camera => programA => /dev/video0 => ffmpeg => .ts files

  


  When camera stopped, programA stop automatically and no new frame arrive to /dev/video0.
I want ffmpeg stop automatically in such situation.
What ffmpeg option should I use ?
Currently I'm using option below, but ffmpeg doesn't stop.

  


  ffmpeg -f video4linux2 -i /dev/video0 -vsync vfr -f hls -c:v h264_nvenc out.m3u8


  


  Edited :
  
I tried to invalidate /dev/video0 but it failed like below.

  


  # modprobe -r v4l2loopback
modprobe: FATAL: Module v4l2loopback is in use.


  


  After I stopped programA and ffmpeg, the command success.
  
ProgramA is kicked by systemd service and restart automatically when it stopped.
  
ffmpeg is kicked by programB, but programB doesn't control programA.
  
But it sounds like good idea to inform B so B can kill ffmpeg.
  
I'll try that way. Thank you.

  


• Live audio using ffmpeg, javascript and nodejs

  8 novembre 2017, par klaus

  I am new to this thing. Please don’t hang me for the poor grammar. I am trying to create a proof of concept application which I will later extend. It does the following : We have a html page which asks for permission to use the microphone. We capture the microphone input and send it via websocket to a node js app.

  JS (Client) :

  var bufferSize = 4096;
  
  var socket = new WebSocket(URL);
  
  var myPCMProcessingNode = context.createScriptProcessor(bufferSize, 1, 1);
  
  myPCMProcessingNode.onaudioprocess = function(e) {
  
    var input = e.inputBuffer.getChannelData(0);
  
    socket.send(convertFloat32ToInt16(input));
  
  }
  
  
  
  function convertFloat32ToInt16(buffer) {
  
    l = buffer.length;
  
    buf = new Int16Array(l);
  
    while (l--) {
  
      buf[l] = Math.min(1, buffer[l])*0x7FFF;
  
    }
  
    return buf.buffer;
  
  }
  
  
  
  navigator.mediaDevices.getUserMedia({audio:true, video:false})
  
                                  .then(function(stream){
  
                                    var microphone = context.createMediaStreamSource(stream);
  
                                    microphone.connect(myPCMProcessingNode);
  
                                    myPCMProcessingNode.connect(context.destination);
  
                                  })
  
                                  .catch(function(e){});

  In the server we take each incoming buffer, run it through ffmpeg, and send what comes out of the std out to another device using the node js ’http’ POST. The device has a speaker. We are basically trying to create a 1 way audio link from the browser to the device.

  Node JS (Server) :

  var WebSocketServer = require('websocket').server;
  
  var http = require('http');
  
  var children = require('child_process');
  
  
  
  wsServer.on('request', function(request) {
  
    var connection = request.accept(null, request.origin);
  
    connection.on('message', function(message) {
  
      if (message.type === 'utf8') { /*NOP*/ }
  
      else if (message.type === 'binary') {
  
        ffm.stdin.write(message.binaryData);
  
      }
  
    });
  
    connection.on('close', function(reasonCode, description) {});
  
    connection.on('error', function(error) {});
  
  });
  
  
  
  var ffm = children.spawn(
  
      './ffmpeg.exe'
  
     ,'-stdin -f s16le -ar 48k -ac 2 -i pipe:0 -acodec pcm_u8 -ar 48000 -f aiff pipe:1'.split(' ')
  
  );
  
  
  
  ffm.on('exit',function(code,signal){});
  
  
  
  ffm.stdout.on('data', (data) => {
  
    req.write(data);
  
  });
  
  
  
  var options = {
  
    host: 'xxx.xxx.xxx.xxx',
  
    port: xxxx,
  
    path: '/path/to/service/on/device',
  
    method: 'POST',
  
    headers: {
  
     'Content-Type': 'application/octet-stream',
  
     'Content-Length': 0,
  
     'Authorization' : 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx',
  
     'Transfer-Encoding' : 'chunked',
  
     'Connection': 'keep-alive'
  
    }
  
  };
  
  
  
  var req = http.request(options, function(res) {});

  The device supports only continuous POST and only a couple of formats (ulaw, aiff, wav)

  This solution doesn’t seem to work. In the device speaker we only hear something like white noise.

  Also, I think I may have a problem with the buffer I am sending to the ffmpeg std in -> Tried to dump whatever comes out of the websocket to a .wav file then play it with VLC -> it plays everything in the record very fast -> 10 seconds of recording played in about 1 second.

  I am new to audio processing and have searched for about 3 days now for solutions on how to improve this and found nothing.

  I would ask from the community for 2 things :

  1. Is something wrong with my approach ? What more can I do to make this work ? I will post more details if required.

  2. If what I am doing is reinventing the wheel then I would like to know what other software / 3rd party service (like amazon or whatever) can accomplish the same thing.

  Thank you.