Mobile App as Universal Remote for AV and Multiroom
We integrate and develop mobile apps that replace all remotes with a single smartphone. One tap — and your LG webOS TV starts Netflix, the Denon AVR-X receiver switches to HDMI 1, and the Sonos One plays a playlist in the living room. The stack is Flutter 3.x with a single codebase for iOS and Android, Kotlin Multiplatform for the gateway, and Node.js for the backend. With over 5 years of experience and more than 10 projects, we deliver reliable control.
Problems We Solve
Different protocols and incompatibility. A single home may use HDMI CEC (for Sony, LG TVs), IP Control (Denon, Yamaha), REST API (Sonos), UPnP (old streamers), and IR (Broadlink). Combining them into a unified interface is a non-trivial task. We implement a universal gateway on Node.js that converts and routes commands between protocols. For example, the "turn off everything" command sends a CEC signal via Pulse-Eight, an IP packet to the receiver, and an IR signal via Broadlink RM4. The gateway operates with latency under 100 ms.
Multiroom audio synchronization. Playing one source in multiple rooms with less than 1 ms latency is a technical challenge solved either by Sonos grouping (REST API) or by Snapcast on Raspberry Pi. Snapcast offers greater flexibility (open source, support for any audio streams), but Sonos is 5 times more accurate in synchronization (1 ms vs 5 ms). For tasks where sync is critical (video+audio in different rooms), we recommend Sonos; for background music, Snapcast. Cost savings on equipment when using Snapcast can reach $300 per zone, which is up to 3 times cheaper than Sonos Ports.
How Multiroom Audio Synchronization Is Achieved
Using Sonos grouping via local REST API provides latency <1 ms. For Snapcast, we configure a server on Raspberry Pi 4 with multiroom streaming. Each Snapcast client (ESP32 or Android) connects to the server via an Ogg stream. This approach can unite up to 6 zones with latency no more than 5 ms. One of our clients saved over $1,000 by integrating Snapcast for 4 zones instead of purchasing additional Sonos Ports.
How We Integrate Devices and What Stack We Use
Example: Sonos and Snapcast Integration
For a client with 6 rooms, we set up multiroom via Sonos Port in each zone. The Flutter app connects to the Sonos HTTP API and allows grouping zones, adjusting volume, and switching tracks. Additionally, we integrated Snapcast for local sources (Kodi media server). Result: a user starts a podcast in one room, and the same track plays in another with synchronization.
AV Control Protocols
| Protocol | Example Devices | Integration Method |
|---|---|---|
| HDMI CEC | Sony, LG TVs | MQTT bridge via Pulse-Eight |
| IP Control | Denon, Yamaha receivers | Telnet/HTTP sockets |
| Sonos API | Sonos One, Beam | REST (local or cloud) |
| Chromecast | Google TV, Chromecast | Cast SDK (Flutter) |
| AirPlay 2 | Apple TV, HomePod | AVRoutePickerView (iOS) |
| IR | Broadlink RM4 | TCP server with backend |
HDMI CEC standard
Multiroom Audio
| Solution | Synchronization | Control |
|---|---|---|
| Sonos | Built-in, <1ms | REST API |
| Snapcast | Network-based, <5ms | REST JSON-RPC |
| AirPlay 2 | Native iOS | AVAudioSession |
Comparison: Snapcast is 5 times less accurate than Sonos (5ms vs 1ms) but wins in flexibility and no brand lock-in. For large systems (10+ zones), Snapcast is more cost-effective — savings can reach $300 per zone.
Technical details of Snapcast synchronization
Snapcast uses a master-slave architecture with a server on Raspberry Pi. Clients buffer audio and adjust playback based on timestamps. The typical sync error is below 5ms, acceptable for background music but not for lip-sync.Work Process
- Analysis — equipment inventory, protocol identification, compatibility testing (2–3 days).
- Design — backend architecture (gateway), mobile framework selection (Flutter/React Native).
- Development — connection implementation, remote UI/UX, testing on real devices (3–6 weeks).
- Integration — IR database setup (1000+ models), HomeKit binding.
- Testing — load testing, offline mode verification.
- Deployment — publish to App Store/Google Play, remote access configuration.
Timelines and What's Included
Basic integration (one protocol, one device) — from 3 weeks. Full remote (multiple protocols, multiroom, IR) — 2–4 months. Budget for a typical project varies depending on complexity: for simple systems from $5,000, for complex up to $25,000. The cost includes the app source code, backend gateway, documentation, testing on your equipment, and one month of support. Contact us for an accurate quote based on your equipment set.
How We Guarantee Quality
We use CI/CD (GitHub Actions, TestFlight), code review, and unit tests. Engineers hold Google (Flutter) and Apple (iOS) certifications. Over 10 multimedia smart home projects. Order a demo version in 2 weeks to evaluate control convenience.
Why Order Development from Us
Experience integrating dozens of protocols, proprietary developments (IR database of 1000+ models, Snapcast bridge). Warranty on all integrations for 6 months. Get a consultation — we will prepare a demo in 2 weeks.