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• ffmpeg only works 2 instances

  31 janvier 2023, par Alex

  I have 3 usb web cameras. Im using Windows 7.

  


  I have 3 usb web cameras

  


  And I need to create 3 video streams :

  


  ffmpeg -f dshow -i video="Full HD webcam" -vcodec libx264 -tune zerolatency -threads 0 -b 900k -f mpegts udp ://localhost:1234

  


  ffmpeg -f dshow -i video=”@device_pnp_~?\usb#vid_1908&pid_2311&mi_00#8&134fde2a&0&0000#65e8773d-8f56-11d0-a3b9-00a0c9223196\global” -vcodec libx264 -tune zerolatency -threads 0 -b 900k -f mpegts udp ://localhost:1233

  


  ffmpeg -f dshow -i video="@device_pnp_~?\usb#vid_1908&pid_2311&mi_00#8&962d85&0&0000#65e8773d-8f56-11d0-a3b9-00a0c9223196\global" -vcodec libx264 -tune zerolatency -threads 0 -b 900k -f mpegts udp ://localhost:1232

  


  But only works 2 any instances of video streams. When I try to create third video stream I get error :

  


  I get error

  


  Can anybody help me, please ?

  


  i tried to create 3 video streams, but could only create 2 instances of ffmpeg process.

  


• A process' child doesn't get killed from killing the parent process

  2 avril 2022, par Impasse

  I am developing an Electron application. In this application, I am spawning a Python process with a file's path as an argument, and the file itself is then passed to ffmpeg (through the ffmpeg-python module) and then goes through some Tensorflow functions.

  


  I am trying to handle the case in which the user closes the Electron app while the whole background process is going. From my tests though, it seems like ffmpeg's process stays up no matter what. I'm on Windows and I'm looking at the task manager and I'm not sure what's going on : when closing the Electron app's window, sometimes ffmpeg.exe will be a single process, some other times it will stay in an Electron processes group.

  


  I have noticed that if I kill Electron's process through closing the window, the python process will also close once ffmpeg has done its work, so I guess this is half-working. The problem is, ffmpeg is doing intensive stuff and if the user needs to close the window, then the ffmpeg process also NEEDS to be killed. But I can't achieve that in any way.

  


  I have tried a couple things, so I'll paste some code :

  


  main.js

  


  // retrieve video data
ipcMain.handle('get-games', async (event, arg) => {
    const spawn = require('child_process').spawn;
    const pythonProcess = spawn('python', ["./backend/predict_games.py", arg]);

    // sets pythonProcess as a global variable to be accessed when quitting the app
    global.childProcess = pythonProcess;

    return new Promise((resolve, reject) => {
        let result = "";

        pythonProcess.stdout.on('data', async (data) => {
            data = String(data);

            if (data.startsWith("{"))
                result = JSON.parse(data);
        });

        pythonProcess.on('close', () => {
            resolve(result);
        })

        pythonProcess.on('error', (err) => {
            reject(err);
        });
    })
});

app.on('before-quit', function () {
    global.childProcess.kill('SIGINT');
});


  


  predict_games.py (the ffmpeg part)

  


  def convert_video_to_frames(fps, input_file):
    # a few useful directories
    local_dir = os.path.dirname(os.path.abspath(__file__))
    snapshots_dir = fr"{local_dir}/snapshots/{input_file.stem}"

    # creates snapshots folder if it doesn't exist
    Path(snapshots_dir).mkdir(parents=True, exist_ok=True)

print(f"Processing: {Path(fr'{input_file}')}")
try:
    (
        ffmpeg.input(Path(input_file))
        .filter("fps", fps=fps)
        .output(f"{snapshots_dir}/%d.jpg", s="426x240", start_number=0)
        .run(capture_stdout=True, capture_stderr=True)
    )
except ffmpeg.Error as e:
    print("stdout:", e.stdout.decode("utf8"))
    print("stderr:", e.stderr.decode("utf8"))


  


  Does anyone have any clue ?

  


• Evolution #3488 : Stocker globalement toutes les requetes passées

  24 juillet 2015, par cedric -

  un compteur global de requêtes, optionnel ou non ça parait pas mal, car a contrario stocker toutes les requêtes peut vite être lourd.
  J’ai vu des sites avec plus de 2000 requete sur une page, et ça alourdirait inutilement la conso mémoire.
  Sinon je pense aussi qu’ajouter ton petit bandeau dans le plugin dev serait une bonne idée