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• Revision 428369293d : vp9_mv_pred : quiet a static analysis warning add an assert to validate pred_mv

  18 mars 2015, par James Zern

  Changed Paths :
   Modify /vp9/encoder/vp9_rd.c

  
  
  vp9_mv_pred : quiet a static analysis warning

  add an assert to validate pred_mv array size

  Change-Id : I532b882b71e2baff3ac76e07ed133ec5a11bd0fc

• Revision fc19243ced : Re-design rate-distortion cost tracking buffers This commit re-designs the per

  10 octobre 2013, par Jingning Han

  Changed Paths :
   Modify /vp9/encoder/vp9_block.h

  
   Modify /vp9/encoder/vp9_onyx_int.h

  
   Modify /vp9/encoder/vp9_rdopt.c

  
  
  Re-design rate-distortion cost tracking buffers

  This commit re-designs the per transformed block rate-distortion
  costs tracking buffers. It removes redundant buffer usage, makes
  the needed context memory allocation per VP9_COMP instance and
  reuses the same buffer sets inside the rate-distortion optimization
  search loop, thereby avoiding repeatedly requiring memory space.

  It reduces speed 0 runtime :

  bus at 2000 kbps from 166763ms to 158967ms,
  football at 600 kbps from 246614ms to 234257ms.

  Both about 5% speed-up. Local tests suggest about 2% to 5% speed-up
  for speed 1 and 2 settings. This does not change compression
  performance.

  Change-Id : I363514c5276b5cf9a38c7251088ffc6ab7f9a4c3

• 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 ?