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• Conversion of .dav [Ubuntu]

  3 juin 2018, par Dauas

  I’ve installed ffmpeg on a Ubuntu Linux Amazon EC2 Server and have a Lorex FLIR NVR directly FTP transferring .DAV files to it. In this system a Java program would then tell the EC2 to convert the .dav to but this is where the problems begin, FFMPEG fails to convert the .dav file and to my surprise there is no Codec for .dav (Though I see mention of it once having been supported). I reach out for a solution to this File Format problem, unfortunately the .dav files are a given as the NVR I have is incapable of transfering any other data type over the web, but what is the best way to convert a .dav file on a linux machine ? My Java program has full access to the Shell. It would also be incredibly helpful if anybody were to know how to get their hands on a .dav codec I could test with ffmpeg. I very much value all of your time helping me on this issue.

• 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.

• MP4Box / FFMPEG concat loses audio after first clip

  17 novembre 2017, par user1615343

  So I am certainly no expert when it comes to either of these tools, but I have a web-based project that’s executing commands on an Amazon Linux server to concatenate two video files that are uploaded.

  Both files are converted to mp4s first using FFMPEG, and those play perfectly in a browser after conversion :

  ffmpeg -i file1.mpg -c:v libx264 -crf 22 -c:a aac -strict -2 -movflags faststart file2.mp4

  Then, I attempt to combine these two resulting mp4s into a single mp4. I tried using FFMPEG to do this but to no avail. Switching to try MP4Box got me much closer : the videos are concatenated together, but the audio stops playing at the end of the first clip, and the second clip is silent.

  MP4Box -force-cat -keepsys -add file.mp4 -cat file2.mp4 out.mp4

  I’ve tried varying versions of the above command with no better results. Any input is greatly appreciated.

  EDIT : info on .mp4 files using

  ffmpeg -i file1.mp4 -i file2.mp4

  ffmpeg -i 1510189259715DogRunsintoGlassDoor_315a03a8e20acfc.mp4 -i
  1510189273549NewhouseMoonMoonneverseenstairsbeforefunnydog_285a03a8e6aab25.mp4

  ffmpeg version N-61041-g52a2138 Copyright (c) 2000-2014 the FFmpeg
  developers

  built on Mar 2 2014 05:45:04 with gcc 4.6 (Debian 4.6.3-1)

  configuration : —prefix=/root/ffmpeg-static/64bit
  —extra-cflags=’-I/root/ffmpeg-static/64bit/include -static’ —extra-ldflags=’-L/root/ffmpeg-static/64bit/lib -static’ —extra-libs=’-lxml2 -lexpat -lfreetype’ —enable-static —disable-shared —disable-ffserver —disable-doc —enable-bzlib —enable-zlib —enable-postproc —enable-runtime-cpudetect —enable-libx264 —enable-gpl —enable-libtheora —enable-libvorbis —enable-libmp3lame —enable-gray —enable-libass —enable-libfreetype —enable-libopenjpeg —enable-libspeex —enable-libvo-aacenc —enable-libvo-amrwbenc —enable-version3 —enable-libvpx

  libavutil 52. 66.100 / 52. 66.100

  libavcodec 55. 52.102 / 55. 52.102

  libavformat 55. 33.100 / 55. 33.100

  libavdevice 55. 10.100 / 55. 10.100

  libavfilter 4. 2.100 / 4. 2.100

  libswscale 2. 5.101 / 2. 5.101

  libswresample 0. 18.100 / 0. 18.100

  libpostproc 52. 3.100 / 52. 3.100

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from
  ’1510189259715DogRunsintoGlassDoor_315a03a8e20acfc.mp4’ :

  Metadata :

  major_brand : isom

  minor_version : 512

  compatible_brands : isomiso2avc1mp41

  encoder : Lavf55.33.100

  Duration : 00:00:04.92, start : 0.023220, bitrate : 634 kb/s

  Stream #0:0(und) : Video : h264 (High) (avc1 / 0x31637661), yuv420p,
  360x360 [SAR 1:1 DAR 1:1], 501 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc
  (default)

  Metadata :

  handler_name : VideoHandler

  Stream #0:1(und) : Audio : aac (mp4a / 0x6134706D), 44100 Hz, mono,
  fltp, 132 kb/s (default)

  Metadata :

  handler_name : SoundHandler

  Input #1, mov,mp4,m4a,3gp,3g2,mj2, from
  ’1510189273549NewhouseMoonMoonneverseenstairsbeforefunnydog_285a03a8e6aab25.mp4’ :

  Metadata :

  major_brand : isom

  minor_version : 512

  compatible_brands : isomiso2avc1mp41

  encoder : Lavf55.33.100

  Duration : 00:00:18.79, start : 0.023220, bitrate : 455 kb/s

  Stream #1:0(und) : Video : h264 (High) (avc1 / 0x31637661), yuv420p,
  362x360 [SAR 1:1 DAR 181:180], 320 kb/s, 29.94 fps, 29.94 tbr, 11976
  tbn, 59.88 tbc (default)

  Metadata :

  handler_name : VideoHandler

  Stream #1:1(eng) : Audio : aac (mp4a / 0x6134706D), 44100 Hz, stereo,
  fltp, 129 kb/s (default)

  Metadata :

  handler_name : SoundHandler

  At least one output file must be specified