Lib Jitsi Meet api - video quality config Issue

Hello , We have setup one-to-many video conference using lib-jitsi-meet API(https://meet.jit.si/libs/lib-jitsi-meet.min.js) and our own servers for other Jitsi components(prosody,jicofo,jvb). The Video-Call is working fine but the video call quality is very low at the receivers end.The quality further deteriorates on addition of new user to the conference. Please let us know what config changes needs to be done to resolve this problem.we tried several configs posted on the community but it did not help.

Lib jitsi config used at our end :

 {
	"options": {
		"hosts": {
			"domain": "***.com",
			"muc": "conference.***.com"
		},
		"bosh": "//***.com:5281/http-bind",
		"clientNode": "http://jitsi.org/jitsimeet"
	},
	"confOptions": {
		"openBridgeChannel": true
	},
	"initOptions": {
		"disableAudioLevels": true,
		"desktopSharingChromeExtId": "mbocklcggfhnbahlnepmldehdhpjfcjp",
		"desktopSharingChromeDisabled": false,
		"desktopSharingChromeSources": [
			"screen",
			"window"
		]
	}
}