Recherche avancée

Sur d’autres sites (13413)

• How to start webcam capturing with javacv

  11 septembre 2017, par suny99

  I am new to JavaCV, i started to learn it but there is lack of documentation. so i need help. My goal in simple. Just take a capture with camera and open it in window, so i dont want to record or anything. Just open camera in window. this is my code :

  public static void main(String[] args) throws FrameGrabber.Exception {
  
  
  
    FrameGrabber grabber = FrameGrabber.createDefault(0);
  
      grabber.start();
  
  
  
      IplImage grabbedImage = converter.convert(grabber.grab());
  
  
  
      CanvasFrame frame = new CanvasFrame("Some Title", CanvasFrame.getDefaultGamma()/grabber.getGamma());
  
      while(grabber.grab()!=null){
  
  
  
  
  
          frame.showImage(grabbedImage);
  
      }
  
      frame.dispose();
  
      grabber.stop();
  
  
  
       }

  So what is bothering me is this : frame.showImage(grabbedImage) ;
  What i need to do to get that image from camera

• FFmpeg -> JSMpeg Websocket Closes Repeatedly

  13 mars 2018, par Kyle Martin

  I’m trying to create a fairly simple streaming server/site. Here’s the current flow :

  • OBS streams to an RTMP URL
  • Nginx accepts the RTMP stream and uses exec-push to have FFmpeg pick up the stream and transcode it
  • FFmpeg transcodes the stream and outputs it to a JSMpeg application, which displays the stream on a webpage.

  When I have my exec_push statement as follows, everything seems to work perfectly, except the browser says Possible garbage data. Skipping. on every frame it receives :

  exec_push /usr/bin/ffmpeg -re -i rtmp://127.0.0.1:1935/$app/$name -f mpeg1video  http://localhost:8080/supersecret;

  This behavior is understandable, because JSMpeg must receive MPEG-TS data, not MPEG1 data. It sees the MPEG1 frames and thinks they’re garbage.

  So through some online research, I found this :

  exec_push /usr/bin/ffmpeg -re -i rtmp://127.0.0.1:1935/$app/$name -c:v copy -c:a copy -f mpegts http://localhost:8080/supersecret;

  Supposedly, this is supposed to transcode my RTMP stream into an MPEG-TS format, which should be compatible with JSMpeg.

  However, with the second version of the command, my FFmpeg -> JSMpeg stream keeps connecting and disconnecting, connecting and disconnecting, and so on. This behavior is observed in terminal :

  Stream Connected: ::1:40208
  
  close
  
  Stream Connected: ::1:40212
  
  close
  
  Stream Connected: ::1:40216
  
  close
  
  Stream Connected: ::1:40220
  
  close
  
  Stream Connected: ::1:40224
  
  close
  
  ...

  What would cause this ? I am pretty certain the issue is in my exec_push command. OBS is perfectly content, which tells me that the stream is making it to the server, and if I do a push, I can do a test push to Ustream just fine, which tells me that Nginx is at least processing the stream with some reasonable degree of success.

  ---

  Disclaimer : I have no idea what I’m talking about. Everything I know about FFmpeg and JSMpeg/Node is from snippets of code that I found online.

• How to fix 'Error : Write EOF' when running a nodejs file which spawns a child process running ffmpeg ?

  16 septembre 2022, par Prithivin Lakshminarayanan

  I am new to nodejs scripting and I am trying to create a program which receives a video file as a buffer and creates a thumbnail from it. This is my code :

  


  create_thumbnail.js :

  


  const { Readable } = require('stream');
const child_process = require('node:child_process');

async function generate_thumbnail(videoFile, callback) {

    const readable = new Readable();
    readable._read = () => {}
    readable.push(videoFile.data)
    readable.push(null)
    const ffmpeg = child_process.spawn('C:\\FFmpeg\\bin\\ffmpeg', ['-i', 'pipe:0', '-vframes', '1', '-vf', 'scale=iw*.5:ih*0.5', '-f', 'mjpeg', 'pipe:1'], { stdio: ['pipe', 'pipe', 'ignore'] })
    readable.pipe(ffmpeg.stdin);

    const buffer = [];

    ffmpeg.stdout.on('data', (data) => {
        buffer.push(data);
    });

    const thumbnail = ffmpeg.stdout.on('end', () => {
        console.log('There will be no more data.');
        var buf = Buffer.concat(buffer);
        callback (buf);
    });
}

module.exports = { generate_thumbnail };


  


  The program is creating a thumbnail successfully for a video which has a few seconds length. It is failing for larger videos with the following error :

  


  node:events:368
      throw er; // Unhandled 'error' event
      ^

Error: write EOF
    at WriteWrap.onWriteComplete [as oncomplete] (node:internal/stream_base_commons:98:16)
Emitted 'error' event on Socket instance at:
    at Socket.onerror (node:internal/streams/readable:773:14)
    at Socket.emit (node:events:390:28)
    at emitErrorNT (node:internal/streams/destroy:157:8)
    at emitErrorCloseNT (node:internal/streams/destroy:122:3)
    at processTicksAndRejections (node:internal/process/task_queues:83:21) {
  errno: -4095,
  code: 'EOF',
  syscall: 'write'


  


  Can someone please let me know the reason for getting this error. How can I fix it ?