Feature: Add Lightweight ONVIF Support for RTSP Server Discovery

[SB2318]

Description

This PR introduces a lightweight, non-conformant ONVIF server for RTSP streaming mode. It enables ScreenStream to be automatically discovered by Network Video Recorders (NVRs) and Video Management Software (VMS) on the local network.

Fixes #346

Key Features

• WS-Discovery Support
  Implemented UDP multicast discovery:

  • IPv4: 239.255.255.250
  • IPv6: FF02::C
  • Port: 3702

  This allows automatic device discovery on the local network.

• SOAP HTTP Server
  Added a lightweight SOAP server running on RTSP_PORT + 1000 (default: 9554) to handle core ONVIF Profile T/S requests.

• Multicast Management
  Added proper permission handling and MulticastLock management to improve multicast reliability across Android versions and device manufacturers.

• UI Integration
  Added a real-time counter in the RTSP Server UI to provide visual feedback whenever an ONVIF probe or request is received.

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Technical Details

• Modules Modified: rtsp, app
• Core Logic: OnvifServer.kt handles low-level XML/SOAP routing without external heavy libraries, keeping the app lightweight.
• Lifecycle Management: The ONVIF server is tightly coupled with the RtspServer lifecycle and starts/stops automatically when streaming begins or ends.
• Permissions: Added android.permission.CHANGE_WIFI_MULTICAST_STATE to allow multicast packet reception.

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Proposed Changes

rtsp

• [NEW] OnvifServer.kt — Core implementation for WS-Discovery and SOAP handlers
• [MODIFIED] RtspServer.kt — Integrated ONVIF server startup/shutdown
• [MODIFIED] RtspStreamingService.kt — Added event handling for ONVIF request tracking
• [MODIFIED] models.kt — Added onvifServerMessagesCount to RtspState
• [MODIFIED] RtspMainScreenUI.kt — Updated UI cards to display ONVIF request counter

app

• [MODIFIED] AndroidManifest.xml — Added required multicast permission

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Verification Report

Environment

• Device: Physical Android device (verified via ADB)
• Network: Local Wi-Fi (IPv4 + IPv6 enabled)
• Tools: Custom Python testing suite (WS-Discovery + SOAP 1.2)

Test Results

Test Case	Method	Result	Notes
WS-Discovery Probe	UDP 3702 Multicast	✅ PASS	Responds with valid ProbeMatch
GetDeviceInformation	SOAP HTTP	✅ PASS	Returns "ScreenStream ONVIF Server"
GetProfiles	SOAP HTTP	✅ PASS	Returns "Profile_1" (Main Stream)
GetStreamUri	SOAP HTTP	✅ PASS	Returns valid rtsp://<ip>:<port>/<path>
UI Feedback	Integration	✅ PASS	Counter increments in real time on probe/request reception

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Status: Ready for Review