How to acquire and execute ffmpeg in real time New data generated by the run process

I want to realize such a function: upload while converting videos.

I tried to do like this, but the result was not satisfactory.
Res outputs results only after ffmpeg completes the operation of the whole process.
```
// await ffmpeg.run'-i', 'video.mp4', '-r', '10', '-b:a', '32k', 'test.mp4');
ffmpeg.run('-i', 'video.mp4', '-r', '10', '-b:a', '32k', 'test.mp4').then(res => {
console.log('success', res);
})
```

Is there any constructive way?