FFmpeg-mt can't convert PNG images to a video, hangs with no callback

I tried to do a simple images-to-video conversion using this library. I already ensured the FFmpeg is loaded and working just fine by transcoding the bunny video.

The command I run is below, but somehow there's no feedback at all (no error, no log, no progress), and the command after it aren't executed (so it's stuck).

And yes I already confirmed the images exist and can be loaded by FFmpeg (by writing => loading => preview on browser). The file is stored inside `images/` in FS and with format `000.png`, `001.png`, etc.

```
await this.ffmpeg.exec([
'-framerate', '1',
'-i', 'images/%03d.png',
'-r', '30',
'output.mp4'
]);
```

The FFmpeg command is also properly detecting the images, there will be FS error otherwise. So something is "stuck" during the execution, I also receive no `progress` callback. I tried using 1 hardcoded image instead of pattern and got the same result.