prevent ffmpeg from opening console window - node.js

Question

I have a node/express server which is used to give streams from IP camera to a website. Everything is working well. I run that webserver with PM2 on a windows server.
The problem : for each stream I have a windows console opening with just nothing logged in. The console reopen when I try to close it.
Is there a way to prevent those console to open ?
Here is the related node.js code :
const { NodeMediaServer } = require('node-media-server');
private _initiate_streams(): void{
DatabaseProvider.instance.camerasDao.getCamerasList().pipe(
take(1)
).subscribe(
(databaseReadOperationResult: DatabaseReadOperationResult<ICamera[]>) => {
if (databaseReadOperationResult.successful === true){
const cameras = databaseReadOperationResult.result;
const tasks = [];
cameras.forEach( camera => {
tasks.push(
{
app : config.get('media_server.app_name'),
mode: 'static',
edge: camera.rtsp_url,
name: camera.stream_name,
rtsp_transport: 'tcp'
}
)
});
const configMediaServer = {
logType: 3, // 3 - Log everything (debug)
rtmp: {
port: 1935,
chunk_size: 60000,
gop_cache: true,
ping: 60,
ping_timeout: 30
},
http: {
port: config.get('media_server.port'),
allow_origin: '*'
},
auth: {
play: true,
api: true,
publish: true,
secret: config.get('salt'),
api_user: 'user',
api_pass: 'password',
},
relay: {
ffmpeg: 'C:\\FFmpeg\\bin\\ffmpeg.exe',
tasks: tasks
}
};
var nms = new NodeMediaServer(configMediaServer)
nms.run();
} else {
// catch exception
}
}
);
}