# Popin HD Video Calling: Recommended Network Guidelines

#### **Overview**

Popin provides real-time HD video calls powered by a scalable **SFU (Selective Forwarding Unit)** backend. It ensures smooth video, clear audio, and low latency through adaptive streaming, **WebSocket-based signaling**, and **Protocol Buffers (Protobuf)** data serialization.

This document outlines the recommended and minimum network requirements for achieving optimal video and audio quality.

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#### **1. ⚡ Bandwidth**

| **Quality**               | **Upload Speed**       | **Download Speed**     | **Notes**                                                       |
| ------------------------- | ---------------------- | ---------------------- | --------------------------------------------------------------- |
| **HD Video (720p–1080p)** | Minimum: 5 Mbps        | Minimum: 5 Mbps        | Functional, occasional quality drops may occur in weak networks |
| **HD Video (720p–1080p)** | Recommended: 8–10 Mbps | Recommended: 8–10 Mbps | Ensures stable, high-quality video and audio                    |

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#### **2. 🌐 Network Quality Guidelines**

| **Parameter**   | **Recommended**                              |
| --------------- | -------------------------------------------- |
| **Latency**     | < 100 ms (ideal), up to 200 ms acceptable    |
| **Packet Loss** | < 1% recommended, noticeable issues above 3% |
| **Jitter**      | < 30 ms recommended                          |

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#### **3. ✅ Recommended**

* **Minimum HD Video:** 5 Mbps upload/download
* **Recommended HD Video:** 8–10 Mbps upload/download
* **Network:** Use wired or strong Wi-Fi connections
* **Device Optimization:** Close unnecessary applications that use network bandwidth during calls

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#### **4. 📊 Minimum Requirements**

| **Resolution** | **Frame Rate (fps)** | **Minimum Bandwidth** |
| -------------- | -------------------- | --------------------- |
| **360p**       | 30 fps               | 450 kbps              |
| **720p**       | 30 fps               | 1.7 Mbps              |
| **1080p**      | 30 fps               | 3 Mbps                |

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#### **5. 🎙️ Published Tracks and Media Configuration**

| **Type**       | **Media** | **Codec / Format** | **Resolution(s)**            |
| -------------- | --------- | ------------------ | ---------------------------- |
| **Microphone** | audio/red | Audio Stream       | —                            |
| **Camera**     | video/VP8 | Video Stream       | 640×360, 1280×720, 1920×1080 |

* **Audio (Microphone):** Encoded using RED for redundancy, improving resilience against packet loss.
* **Video (Camera):** Published in multiple resolutions (360p, 720p, 1080p) to support adaptive **simulcast streaming**.

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#### **6. 🎞️ Codec Priority and Compatibility**

Popin prioritizes codecs in the following order to balance performance, quality, and compatibility:

**Codec Priority List:**

1. **VP8** — Default codec for broad compatibility and low latency.
2. **H.264** — Hardware-accelerated and widely supported across devices.
3. **VP9** — Provides improved compression for modern browsers.
4. **AV1** — Offers high-quality video at lower bitrates (emerging support).
5. **H.265 (HEVC)** — Supported on select clients for advanced compression and 4K optimization.

Popin automatically negotiates the optimal codec based on participant capabilities and real-time network conditions.

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#### **7. ⚙️ Backend Architecture**

Popin’s media infrastructure uses a **Selective Forwarding Unit (SFU)** design to efficiently route video and audio streams with minimal latency.

**Technical Highlights:**

* **Transport Protocol:** WebRTC media transport with **SRTP encryption**.
* **Signaling:** WebSocket-based with **Protocol Buffers (Protobuf)** serialization for minimal overhead.
* **Adaptive Bitrate (ABR):** Automatically adjusts stream quality based on bandwidth and device performance.
* **Simulcast Support:** Multiple simultaneous video layers (360p, 720p, 1080p) for optimized network usage.

This architecture delivers scalability, low latency, and high-quality experiences for both one-to-one and multiparty video sessions.