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• Android JavaCV FFmpeg webstream to local static website

  26 mars 2017, par Thomas Devoogdt

  For my integrated test I’m working on an application that needs to provide a live stream to a locally hosted website. I’ve already built a working site that run’s on nanohttpd. This application performs also special image processing. Therefore I use JavaCV. The library is working perfectly and all cpp bindings are working too.

  My question : How to set up a live stream that can directly be played in a static site hosted by nanohttpd ? - I am on the right way ?

  My code :

  init :

  private void initLiveStream() throws FrameRecorder.Exception {
  
      /* ~~~ https://github.com/bytedeco/javacv/issues/598 ~~~ */
  
      frameRecorder = new FFmpegFrameRecorder("http://localhost:9090", imageWidth, imageHeight, 0);
  
      frameRecorder.setVideoOption("preset", "ultrafast");
  
      frameRecorder.setVideoCodec(avcodec.AV_CODEC_ID_H264);
  
      frameRecorder.setAudioCodec(0);
  
      frameRecorder.setPixelFormat(avutil.AV_PIX_FMT_YUV420P);
  
      frameRecorder.setFormat("webm");
  
      frameRecorder.setGopSize(10);
  
      frameRecorder.setFrameRate(frameRate);
  
      frameRecorder.setVideoBitrate(5000);
  
      frameRecorder.setOption("content_type","video/webm");
  
      frameRecorder.setOption("listen", "1");
  
      frameRecorder.start();
  
  }

  In my CameraView :

  @Override
  
  public void onPreviewFrame(byte[] data, Camera camera) {
  
      Camera.Size size = camera.getParameters().getPreviewSize();
  
      Frame frame = new AndroidFrameConverter().convert(data, size.width, size.height);
  
      try {
  
           if(frameRecorder!=null){
  
               frameRecorder.record(frame);
  
           }
  
       } catch (FrameRecorder.Exception e) {
  
           e.printStackTrace();
  
       }
  
   }

  Here is one of the stack traces that ar shown frequently in my search to the solution :

  org.bytedeco.javacv.FrameRecorder$Exception: avio_open error() error -111: Could not open 'http://localhost:9090'

  I couldn’t find any other thread addressing this specific issue.

  Thanks in advance

  EDIT

  Thanks to Chester Cobus, Here is my used code :

  Websocket :

  //Constructor
  
  AsyncHttpServer serverStream = new AsyncHttpServer();
  
  List<websocket> sockets = new ArrayList&lt;>();
  
  
  
  //http://stackoverflow.com/a/33021907/5500092
  
  //I'm planning to use more sockets. This is the only uniform expression I found.
  
  serverStream.websocket("/((?:[^/]*/)*)(.*)", new AsyncHttpServer.WebSocketRequestCallback() {
  
       @Override
  
       public void onConnected(final WebSocket webSocket, AsyncHttpServerRequest request) {
  
           String uri = request.getPath();
  
           if (uri.equals("/live")) {
  
               sockets.add(webSocket);
  
  
  
               //Use this to clean up any references to your websocket
  
               webSocket.setClosedCallback(new CompletedCallback() {
  
                   @Override
  
                   public void onCompleted(Exception ex) {
  
                       try {
  
                           if (ex != null)
  
                               Log.e("WebSocket", "Error");
  
                       } finally {
  
                           sockets.remove(webSocket);
  
                       }
  
                   }
  
               });
  
           }
  
       }
  
  });
  
  
  
  //Updater (Observer pattern)
  
  @Override
  
  public void updated(byte[] data) {
  
      for (WebSocket socket : sockets) {
  
           socket.write(new ByteBufferList(data));
  
      }
  
  }
  
  </websocket>

  Record Acitivy

  private long start_time = System.currentTimeMillis();
  
  
  
  @Override
  
  public void onPreviewFrame(byte[] data, Camera camera) {
  
      long now_time = System.currentTimeMillis();
  
      if ((now_time - start_time) > 250) {
  
          start_time = now_time;
  
          //https://forums.xamarin.com/discussion/40991/onpreviewframe-issue-converting-preview-byte-to-android-graphics-bitmap
  
          Camera.Size size = camera.getParameters().getPreviewSize();
  
          YuvImage image = new YuvImage(data, ImageFormat.NV21, size.width, size.height, null);
  
          ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
  
          image.compressToJpeg(new Rect(0, 0, size.width, size.height), 60, byteArrayOutputStream);
  
          MainActivity.getWebStreamer().updated(byteArrayOutputStream.toByteArray());
  
      }
  
  }

  JavaScript

  var socket;
  
  var imageElement;
  
  
  
  /**
  
   * path - String.Format("ws://{0}:8090/live", Window.Location.HostName)
  
   * image - HTMLImageElement
  
   */
  
  function imageStreamer(path, image) {
  
      imageElement = image;
  
      socket = new WebSocket(path);
  
  
  
      socket.onmessage = function(msg) {
  
          var arrayBuffer = msg.data;
  
          var reader = new FileReader();
  
          reader.onload = function(e) {
  
              imageElement.src = e.target.result;
  
          };
  
          reader.readAsDataURL(arrayBuffer);
  
      };
  
  }

• GC and onTouch cause Fatal signal 11 (SIGSEGV) error in app using ffmpeg through ndk

  30 janvier 2015, par grzebyk

  I am getting a nasty but well known error while working with FFmpeg and NDK :

  A/libc(9845): Fatal signal 11 (SIGSEGV), code 1, fault addr 0xa0a9f000 in tid 9921 (AsyncTask #4)

  UPDATE

  After couple hours i found out that there might be two sources of the problem. One was related to multithreading. I checked it and I fixed it. Now the app crashes ONLY when the video playback (ndk) is on.

  I put a "counter" in touch event

    surfaceSterowanieKamera.setOnTouchListener(new View.OnTouchListener() {
  
              int counter = 0;
  
              @Override
  
              public boolean onTouch(View v, MotionEvent event) {             
  
                  if ((event.getAction() == MotionEvent.ACTION_MOVE)){
  
                      Log.i(TAG, "counter = " + counter);
  
                      //cameraMover.setPanTilt(some parameters);
  
                      counter++;
  
                   }

  And I started disabling other app functionalities one by one, but no video. I found out, that with every single functionality less, it takes app longer to crush - counter reaches higher values. After turning off everything besides video playback and touch interface (cameraMover.setPanTilt() commented out) the app crushes usually when counter is between 1600 - 1700.

  In such case logcat shows the above error and GC related info. For me it seems like GC is messing up with the ndk.

  01-23 12:27:13.163: I/Display Activity(20633): n = 1649
  
  01-23 12:27:13.178: I/art(20633): Background sticky concurrent mark sweep GC freed 158376(6MB) AllocSpace objects, 1(3MB) LOS objects, 17% free, 36MB/44MB, paused 689us total 140.284ms
  
  01-23 12:27:13.169: A/libc(20633): Fatal signal 11 (SIGSEGV), code 1, fault addr 0x9bd6ec0c in tid 20734 (AsyncTask #3)

  Why is GC causing problem with ndk part of application ?

  ---

  ORIGINAL PROBLEM

  What am I doing ?

  I am developing an application that streams live video feed from a webcam and enables user to pan and tilt the remote camera. I am using FFmpeg library built with NDK to achieve smooth playback with little delay.

  I am using FFMpeg library to connect to the video stream. Then the ndk part creates bitmap, does the image processing and render frames on the SurfaceView videoSurfaceView object which is located in the android activity (java part).

  To move the webcam I created a separate class - public class CameraMover implements Runnable{/**/}. This class is a separate thread that connects through sockets with the remote camera and manages tasks connected ONLY with pan-tilt movement.

  Next in the main activity i created a touch listener

  videoSurfaceView.setOnTouchListener(new View.OnTouchListener() {/**/
  
  cameraMover.setPanTilt(some parameters);
  
  /**/}

  which reads user’s finger movement and sends commands to the camera.

  All tasks - moving camera around, touch interface and video playback are working perfectly when the one of the others is disabled, i.e. when I disable possibility to move camera, I can watch video streaming and register touch events till the end of time (or battery at least). The problem occurs only when task are configured to work simultaneously.

  I am unable to find steps to reproduce the problem. It just happens, but only after user touches the screen to move camera. It can be 15 seconds after first interaction, but sometimes it takes app 10 or more minutes to crash. Usually it is something around a minute.

  What have I done to fix it ?

  • I tried to display millions of logs in logcat to find an error but
    the last log was always different.
  • I created a transparent surface, that I put over the videoSurfaceView and assigned touch listener to it. It all ended in the same error.
  • As I mentioned before, I turned off some functionalities to find which one produces the error, but it appears that error occurs only when everything is working simultaneously.

  Types of the error

  Almost every time the error looks like this :

  A/libc(11528): Fatal signal 11 (SIGSEGV), code 1, fault addr 0x9aa9f00c in tid 11637 (AsyncTask #4)

  the difference between two errors is the number right after libc, addr number and tid number. Rarely the AsyncTask number varies - i received #1 couple times but I was unable to reproduce it.

  Question

  How can i avoid this error ? What can be the source of it ?

• Senior Software Engineer for Enterprise Analytics Platform

  28 janvier 2016, par Matthieu Aubry — Uncategorized

  We’re looking for a lead developer to work on Piwik Enterprise Analytics core platform software. We have some exciting challenges to solve and need you !

  You’ll be working with both fellow employees and our open-source community. Piwik staff lives in New Zealand, Europe (Poland, Germany) and in the U.S. We do the vast majority of our collaboration online.

  We are a small, flexible team, so when you come aboard, you will play an integral part in engineering. As a leader you’ll help us to prioritise work and grow our community. You’ll help to create a welcoming environment for new contributors and set an example with your development practices and communications skills. You will be working closely with our CTO to build a future for Piwik.

  Key Responsibilities

  • Strong competency coding in PHP and JavaScript.
  • Scaling existing backend system to handle ever increasing amounts of traffic and new product requirements.
  • Outstanding communication and collaboration skills.
  • Drive development and documentation of internal and external APIs (Piwik is an open platform).
  • Help make our development practices better and reduce friction from idea to deployment.
  • Mentor junior engineers and set the stage for personal growth.

  Minimum qualifications

  • 5+ years of experience in product development, security, usable interface design.
  • 5+ years experience building successful production software systems.
  • Strong competency in PHP5 and JavaScript application development.
  • Skill at writing tests and reviewing code.
  • Strong analytical skills.

  Location

  • Remote work position !
  • or you can join us in our office based in Wellington, New Zealand or in Wrocław, Poland.

  Benefits

  • Competitive salary.
  • Remote work is possible.
  • Yearly meetup with the whole team abroad.
  • Be part of a successful open source company and community.
  • In our Wellington (NZ) and Wroclaw (PL) offices : snacks, coffee, nap room, Table football, Ping pong…
  • Regular events.
  • Great team of people.
  • Exciting projects.

  Learn more

  Learn more what it’s like to work on Piwik in our blog post

  About Piwik

  At Piwik we develop the leading open source web analytics platform, used by more than one million websites worldwide. Our vision is to help the world liberate their analytics data by building the best open alternative to Google Analytics.

  The Piwik platform collects, stores and processes a lot of information : hundreds of millions of data points each month. We create intuitive, simple and beautiful reports that delight our users.

  Apply online

  To apply for this position, please Apply online here. We look forward to receiving your applications !