🎥 ViCast-NIP

ViCast is a high-performance C++ broadcast gateway for real-time video routing between NDI® network video, GPU desktop capture, and SDI broadcast hardware.
Designed for 24/7 production environments, ViCast delivers ultra-low latency video processing using SIMD-accelerated pipelines, lock-free frame pools, and multithreaded architecture.
It automatically manages signal routing, failover, synchronization, and broadcast output, making it ideal for studio automation, live production, and IP video infrastructure.

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📌 Table of Contents

• 🧠 Architecture Overview
• ⚡ Core Features
• 🔄 Input Failover Logic
• 🔄 Video Routing Pipeline
• 📊 Output Capability Matrix
• ⚙️ Supported Pixel Formats
• ⏱ Timing & Synchronization
• 🚀 Performance Design
• 🧩 Internal Processing Pipeline
• 📡 Broadcast Integration
• 💻 System Requirements
• ⚙️ Configuration
• Key Parameters
• 📺 Supported DeckLink Video Modes
• 🛠️ Building the Project
• 📄 License
• 🙏 Acknowledgements
• 🎬 Master Signal & Failover Diagram

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🧠 Architecture Overview

INPUT

• GPU Desktop Capture (DXGI duplication)
• NDI Primary / Backup

PROCESS

• libyuv scaling
• Fill / Key generation
• Frame pool (zero allocation)

OUTPUT

• NDI Fill
• NDI Key
• NDI Embedded
• DeckLink SDI (V210 10-bit)

TIMING

• DeckLink Genlock (if present)
• Software frame pacing fallback

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⚡ Core Features

• Intelligent Input Routing
  Prioritizes local GPU Desktop Duplication. If unavailable, switches to NDI sources automatically.

• Automatic NDI Failover
  Monitors Primary NDI source. If signal drops beyond a configurable threshold, switches to Backup seamlessly.

• Zero-Overhead Desktop Capture
  Uses DXGI API for 60fps capture with minimal CPU overhead and direct GPU memory access.

• Multi-Channel NDI Output
  Simultaneously broadcasts Fill, Key (Alpha), and Embedded RGBA streams.

• DeckLink SDI Integration
  Professional 10-bit V210 output with optional hardware Genlock / Reference lock.

• Thread-Safe Telemetry
  Real-time console dashboard for routing, FPS, dropped frames, clock drift, and system health.

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🔄 Input Failover Logic

Priority Order:

1. GPU Desktop Capture
2. NDI Primary
3. NDI Backup

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🔄 Video Routing Pipeline

The engine dynamically switches between Desktop Capture, NDI Primary, and NDI Backup sources.
Failover engages automatically when frames are dropped beyond flapThreshold.

Priority Table:

Priority	Source
1	GPU Desktop Capture
2	NDI Primary
3	NDI Backup

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📊 Output Capability Matrix

Feature	NDI Fill	NDI Key	NDI Embedded	SDI (DeckLink)
Color	✓	✗	✓	✓
Alpha	✗	✓	✓	Optional
10-bit	✓	✓	✓	✓
Hardware Sync	Network	Network	Network	✓
Broadcast Switcher Compatible	✓	✓	✓	✓

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⚙️ Supported Pixel Formats

Format	Bit Depth	Usage
RGBA	8-bit	GPU capture
UYVY	8-bit	NDI pipeline
V210	10-bit	SDI output
YUV 4:2:2	10-bit	DeckLink hardware

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⏱ Timing & Synchronization

Hardware Genlock (Preferred)

• Locks output to external reference if present (Blackburst, Tri-Level, or House Ref).
• Ensures frame-accurate sync across devices.

Internal Clock (Fallback)

• High-precision software timer if no Genlock detected.
• Maintains stable frame pacing for NDI and single-device SDI pipelines.

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🚀 Performance Design

• SIMD acceleration via libyuv
• Lock-free frame pools
• Zero dynamic allocation in hot paths
• Multithreaded pipeline
• GPU-assisted capture

Typical Latency:

Pipeline	Latency
Desktop → NDI	~1 frame
NDI → SDI	~1–2 frames
Desktop → SDI	~1 frame

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🧩 Internal Processing Pipeline

INPUT

• GPU Desktop Capture (DXGI)
• NDI Primary / Backup

PROCESS

• Frame pool (zero allocation)
• libyuv scaling & color conversion
• Fill / Key generation

OUTPUT

• NDI Fill
• NDI Key
• NDI Embedded
• DeckLink SDI (V210)

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📡 Broadcast Integration

System	Compatibility
NDI Production workflows	✓
SDI Switchers	✓
Graphics Engines	✓
IP Video Infrastructure	✓
Studio Automation	✓

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💻 System Requirements

Operating System

• Windows 10 / 11 (64-bit)

Hardware (Optional)

• Blackmagic DeckLink card for SDI output

Dependencies

Dependency	Purpose
NDI® SDK	Network video transport
Blackmagic Desktop Video	DeckLink drivers
Visual Studio 2022 (MSVC v143)	Build toolchain
libyuv	SIMD video processing

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⚙️ Configuration

• Controlled via config.json in AppData/Local/ViCast or executable folder.
• Blank = Disabled design, e.g., "ndiOutputEmbedded": "" disables the sender.

Example config.json

{
  "enableDesktopCapture": true,
  "enableNdiInput": true,
  
  "ndiInputPrimary": "STUDIO-PC (Mix 1)",
  "ndiInputBackup": "STUDIO-PC (Mix 2)",
  
  "flapThreshold": 5,
  
  "ndiOutputFill": "ViCast Fill",
  "ndiOutputKey": "ViCast Key",
  "ndiOutputEmbedded": "ViCast NDI",
  
  "outputWidth": 1920,
  "outputHeight": 1080,
  "outputFpsN": 25,
  "outputFpsD": 1,
  
  "forceProgressive": true,
  "forceInterlaced": false,
  
  "ndiHighestQuality": true,
  "clockVideo": true,
  "clockAudio": true,
  "pixelFormat": "v210",
  
  "enableDeckLink": false,
  "decklinkDevices": [
    {
      "name": "DeckLink 8K Pro",
      "outputMode": "1080p25",
      "keyOutput": true
    }
  ],
  "verboseLogging": true
}

Key Parameters

• outputFpsN / outputFpsD: frame rate fraction (e.g., 60000/1000 = 60fps)
• enableDesktopCapture: overrides NDI inputs if true
• flapThreshold: consecutive dropped frames before failover
• enableDeckLink: enables SDI output (V210 10-bit)

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🛠️ Building the Project

1⃣ Clone the repository

git clone https://github.com/vivek-kr-git/ViCast

2️⃣ Install Dependencies

Install the following:

• NDI SDK
• DeckLink SDK
• libyuv

Add them to Visual Studio:

• Project Properties → Include Directories
• Project Properties → Linker Dependencies

3️⃣ Build

• Configuration: Release
• Platform: x64

⚠️ Debug builds may not sustain real-time 60fps performance due to disabled compiler optimizations.

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📊 Performance Characteristics

ViCast is optimized for real-time broadcast workloads.
Key techniques include:

• Lock-free frame pools
• SIMD processing
• Zero dynamic allocation in hot paths
• Multithreaded pipeline
• Hardware synchronization

Typical latency: ~1–2 frames (depending on hardware and pipeline configuration)

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📄 License

ViCast is licensed under the Apache License 2.0. See LICENSE for details.

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🙏 Acknowledgements

• NDI® by Vizrt
• DeckLink SDK by Blackmagic Design
• libyuv by Google

See THIRDPARTY.md for full copyright and licensing information.

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☕ Support

If you like ViCast-NIP and want to support development, you can buy me a coffee:

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📸 Demo

Example of ViCast in action – desktop capture routed to NDI and SDI output.

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📺 Supported DeckLink Video Modes

Standard Definition (SD)

Resolution	Frame Rate	Scan Type	DeckLink Mode
720×486	29.97	Interlaced	bmdModeNTSC
720×486	23.98	Progressive	bmdModeNTSC2398
720×486	29.97	Progressive	bmdModeNTSCp
720×576	25	Interlaced	bmdModePAL
720×576	25	Progressive	bmdModePALp

HD 720 (Progressive Only)

Resolution	Frame Rate	Scan Type	DeckLink Mode
1280×720	50	Progressive	bmdModeHD720p50
1280×720	59.94	Progressive	bmdModeHD720p5994
1280×720	60	Progressive	bmdModeHD720p60

HD 1080 Interlaced

Resolution	Frame Rate	Scan Type	DeckLink Mode
1920×1080	25	Interlaced	bmdModeHD1080i50
1920×1080	59.94	Interlaced	bmdModeHD1080i5994
1920×1080	60	Interlaced	bmdModeHD1080i6000

HD 1080 Progressive

Resolution	Frame Rate	Scan Type	DeckLink Mode
1920×1080	23.98	Progressive	bmdModeHD1080p2398
1920×1080	24	Progressive	bmdModeHD1080p24
1920×1080	25	Progressive	bmdModeHD1080p25
1920×1080	29.97	Progressive	bmdModeHD1080p2997
1920×1080	30	Progressive	bmdModeHD1080p30
1920×1080	50	Progressive	bmdModeHD1080p50
1920×1080	59.94	Progressive	bmdModeHD1080p5994
1920×1080	60	Progressive	bmdModeHD1080p6000

Legacy 2K Film (1556 lines)

Resolution	Frame Rate	Scan Type	DeckLink Mode
2048×1556	23.98	Progressive	bmdMode2k2398
2048×1556	24	Progressive	bmdMode2k24
2048×1556	25	Progressive	bmdMode2k25

2K DCI

Resolution	Frame Rate	Scan Type	DeckLink Mode
2048×1080	23.98	Progressive	bmdMode2kDCI2398
2048×1080	24	Progressive	bmdMode2kDCI24
2048×1080	25	Progressive	bmdMode2kDCI25
2048×1080	29.97	Progressive	bmdMode2kDCI2997
2048×1080	30	Progressive	bmdMode2kDCI30
2048×1080	50	Progressive	bmdMode2kDCI50
2048×1080	59.94	Progressive	bmdMode2kDCI5994
2048×1080	60	Progressive	bmdMode2kDCI60

4K UHD

Resolution	Frame Rate	Scan Type	DeckLink Mode
3840×2160	23.98	Progressive	bmdMode4K2160p2398
3840×2160	24	Progressive	bmdMode4K2160p24
3840×2160	25	Progressive	bmdMode4K2160p25
3840×2160	29.97	Progressive	bmdMode4K2160p2997
3840×2160	30	Progressive	bmdMode4K2160p30
3840×2160	50	Progressive	bmdMode4K2160p50
3840×2160	59.94	Progressive	bmdMode4K2160p5994
3840×2160	60	Progressive	bmdMode4K2160p60

4K DCI

Resolution	Frame Rate	Scan Type	DeckLink Mode
4096×2160	23.98	Progressive	bmdMode4kDCI2398
4096×2160	24	Progressive	bmdMode4kDCI24
4096×2160	25	Progressive	bmdMode4kDCI25
4096×2160	29.97	Progressive	bmdMode4kDCI2997
4096×2160	30	Progressive	bmdMode4kDCI30
4096×2160	50	Progressive	bmdMode4kDCI50
4096×2160	59.94	Progressive	bmdMode4kDCI5994
4096×2160	60	Progressive	bmdMode4kDCI60

8K UHD

Resolution	Frame Rate	Scan Type	DeckLink Mode
7680×4320	23.98	Progressive	bmdMode8K4320p2398
7680×4320	24	Progressive	bmdMode8K4320p24
7680×4320	25	Progressive	bmdMode8K4320p25
7680×4320	29.97	Progressive	bmdMode8K4320p2997
7680×4320	30	Progressive	bmdMode8K4320p30
7680×4320	50	Progressive	bmdMode8K4320p50
7680×4320	59.94	Progressive	bmdMode8K4320p5994
7680×4320	60	Progressive	bmdMode8K4320p60

8K DCI

Resolution	Frame Rate	Scan Type	DeckLink Mode
8192×4320	23.98	Progressive	bmdMode8kDCI2398
8192×4320	24	Progressive	bmdMode8kDCI24
8192×4320	25	Progressive	bmdMode8kDCI25
8192×4320	29.97	Progressive	bmdMode8kDCI2997
8192×4320	30	Progressive	bmdMode8kDCI30
8192×4320	50	Progressive	bmdMode8kDCI50
8192×4320	59.94	Progressive	bmdMode8kDCI5994
8192×4320	60	Progressive	bmdMode8kDCI60

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