Recherche avancée

Sur d’autres sites (14967)

• 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 ?

  


• avcodec/mpeg4videodec : Fix runtime error : signed integer overflow : 134527392 * 16...

  3 mars 2017, par Michael Niedermayer

  avcodec/mpeg4videodec : Fix runtime error : signed integer overflow : 134527392 * 16 cannot be represented in type ’int’
  This checks the sprite delta intermediates for overflow
  
  Fixes : 716/clusterfuzz-testcase-4890287480504320
  Found-by : continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/mpeg4videodec.c

• How to add custom external video filter to ffmpeg at runtime ?

  9 décembre 2019, par alex

  Trying to build ffplay app that uses ffmpeg LGPL build with custom filter that I want to plug in during runtime. Differently from adding custom filter during compilation described scenario is not documented, thus tried to experiment. Tried executing avfilter_register and avfilter_graph_alloc_filter functions before avfilter_graph_parse_ptr with avfilter_graph_parse_ptr resulting in -22 return value (Invalid argument).

  Filter graph string : [in] split [T1], fifo, [T2] overlay=0:H/2 [out]; [T1] fifo, crop=iw:ih/2:0:ih/2, my_edgedetect=low=0.1:high=0.4 [T2]

  Lines added to configure_filtergraph function in ffplay.c :

          if ((ret = avfilter_register(&ff_vf_edgedetect)) < 0)
  
              goto fail;
  
          if ((ret = avfilter_graph_alloc_filter(graph, &ff_vf_edgedetect, ff_vf_edgedetect.name)) < 0)
  
              goto fail;

  Custom edge detect filter name (AVFilter.name) changed to my_edgedetect.

  ---

  What is the proper way to register custom filter during runtime ?

  ---

  P.S.
  Same question on Zeranoa forum