FastScreenCapture 0.1.1 [ALPHA] — Ultra-Fast Uncompressed Screen Capture CLI & Global Hotkey Daemon for Java

⚡ Bit-perfect uncompressed screen grabs and direct 60 FPS video recording. Direct DirectX 11 DXGI GPU capture, zero GC pressure, direct RAM pipe to FFmpeg, and native system-wide hotkeys.

FastScreenCapture was born out of frustration while recording high-frequency 3D particle benchmarks for FastAnimation: standard tools like ShareX and the native Windows 11 Snipping Tool introduced heavy compression blur, frame drops, and severe moiré interference on fine particle lines.

Instead of burning CPU on heavy compression or writing 30 GB of uncompressed bitmaps to the SSD, FastScreenCapture extracts pristine frames straight from DXGI Desktop Duplication and streams raw BGRA buffers directly into an optimized FFmpeg pipe — keeping CPU usage near 0% with zero dropped frames.

▶️ Watch the 60 FPS Demo Video on YouTube: https://youtu.be/CBbNffXXvVc

FastScreenCapture.bat --daemon

Runs quietly in the background without UI lag or focus interruption:

• [F9]: Toggle 60 FPS Video Recording (starts/stops lossless MP4 stream via FFmpeg pipe with instant +faststart playback).
• [F10]: Instant Bit-Perfect Screenshot (uncompressed 32-bit BMP straight to grabs/).
• Acoustic feedback: High tone (1200 Hz) confirms recording start; low tone (450 Hz) confirms recording stop.

FastScreenCapture.bat

Captures the entire desktop at hardware resolution and writes a bit-perfect uncompressed .bmp into grabs/.

FastScreenCapture.bat --record 60 --fps 60 --out fastanimation_demo.mp4

• Why FastScreenCapture?
• Key Features
• Real-World Use Cases
• Architecture & Pipeline
• Performance Benchmarks
• Installation
• Documentation
• Platform Support
• License
• Related Projects

Traditional capture tools are poorly suited for latency-critical tasks, high-frequency analysis, and bit-accurate image verification:

1. Sluggish UI & Desktop Freezes: Snipping Tool and ShareX interrupt desktop interaction, causing UI stutter and focus drops.
2. Forced CPU Compression Overhead: Enforcing PNG/JPEG encoding burns 20–100 ms of CPU time per frame and creates compression artifacts.
3. Severe GC Stalls: Legacy Java capture tools allocate tens of megabytes per frame on the JVM heap.

FastScreenCapture bypasses these limitations:

• Direct DXGI Desktop Duplication: Raw GPU framebuffer extraction in <1 ms via FastScreen.
• Bit-Perfect 100% Raw BMP: Lossless uncompressed files instantly openable in any viewer or editor.
• Global Low-Latency Hooks: Instantaneous event response via FastHotkey.
• Zero JVM GC Allocations: Zero-copy off-heap memory path straight to disk.

• ⚡ Instant Capture Throughput — Captures and commits full desktop frames in milliseconds.
• 🎯 Bit-Perfect Quality — 100% uncompressed raw BGRA/ARGB data without lossy artifacts.
• ⌨️ Global Native Hotkeys — Background daemon mode listening for F1–F12 or PrintScreen.
• 📁 Direct-to-Disk DMA — Streamlined Little-Endian BMP serialization bypassing OS memory bloat.
• 🔗 FastJava Synergy — Powered by FastScreen, FastHotkey, and FastCore.

• ⚡ Zero-Lag Screenshot Hotkey Daemon: Replace bloated screenshot utilities (ShareX, Windows Snipping Tool) with a background process that commits full-resolution desktop captures in <6 ms without UI pauses or window flashes.
• 🎯 Bit-Exact Visual Regression & UI Testing: Capture pristine, 100% uncompressed frames during automated UI / rendering test suites (e.g., Selenium, JavaFX, OpenGL, Vulkan) where PNG compression artifacts or color subsampling would cause false positive diffs.
• 🏎️ High-Speed Gameplay & Event Bursting: Burst-capture 5–60 consecutive uncompressed frames (--burst 10) at full monitor refresh rates during rapid in-game action, physics anomalies, or micro-stutters.
• 🤖 Dataset Generation for Vision & OCR Pipelines: Rapidly collect hundreds of raw screen patches per second without GPU/CPU encoding bottlenecks for training OCR, layout parsing, or object detection models.
• 📊 Financial & High-Frequency Trading Telemetry: Archive pixel-accurate order book states, charts, and millisecond ticker snapshots without introducing thread latency to execution algorithms.

┌─────────────────────────────────────────────────────────────────────────────┐
│                 Windows OS Global Hotkey Daemon (FastHotkey)                │
│                 [F10] Single Screenshot  |  [F9] Toggle Video               │
└──────────────────────────────────────┬──────────────────────────────────────┘
                                       │ Instant Key Event (<0.1ms)
                                       ▼
┌─────────────────────────────────────────────────────────────────────────────┐
│                       FastScreenCapture Daemon Engine                       │
└──────────────────────────────────────┬──────────────────────────────────────┘
                                       │ Direct DXGI Extraction (<1ms)
                                       ▼
┌─────────────────────────────────────────────────────────────────────────────┐
│                                 FastScreen                                  │
│                  (DirectX 11 DXGI GPU Desktop Duplication)                  │
└──────────────────┬───────────────────────────────────────┬──────────────────┘
                   │                                       │
    [F10] Single Frame                             [F9] 60 FPS Stream
                   ▼                                       ▼
┌─────────────────────────────────────┐ ┌─────────────────────────────────────┐
│            FastBmpWriter            │ │     Zero-Copy Direct Pipe (RAM)     │
│    (54-Byte Top-Down DIB Header)    │ │    Direct Memory -> FFmpeg stdin    │
└──────────────────┬──────────────────┘ └──────────────────┬──────────────────┘
                   │ Direct NIO Channel Write              │ Lossless H.264 +faststart
                   ▼                                       ▼
┌─────────────────────────────────────┐ ┌─────────────────────────────────────┐
│       Bit-Perfect Raw BMP           │ │     Instant-Play 60 FPS MP4         │
│     (NVMe Storage: grabs/*.bmp)     │ │   (NVMe Storage: grabs/*.mp4)       │
└─────────────────────────────────────┘ └─────────────────────────────────────┘

Measured on official JMH benchmark suite (run-benchmark.bat):

Benchmark                                     Mode  Cnt   Score   Error   Units
Benchmark.benchmarkFastScreenCaptureBmpWriter thrpt    3   0.221          ops/ms

• Throughput: >220 full frames / sec uncompressed 32-bit (800×600) written directly to disk.
• Heap GC Pressure: 0 bytes temporary allocations on the JVM heap.

Measured during continuous 60-second real-time capture of the FastAnimation demo (1440×960 @ 60 FPS):

Metric                               Value          Impact
DXGI Desktop Acquisition Latency     < 0.8 ms       Sub-millisecond frame availability
Direct Memory Pipe Write Latency     < 0.3 ms       Immediate transfer to encoder stdin
Sustained Stream Throughput          60.0 FPS       100% stable framerate, 0 dropped frames
Average Process CPU Overhead         < 1.0 %        Barely registers during intense 3D simulations
Disk I/O Churn                       0 MB/s temp    Zero intermediate disk writes; pure RAM pipe

To enable high-speed direct-pipe video recording without disk I/O bottlenecks, FastScreenCapture requires FFmpeg. FastScreenCapture will automatically detect FFmpeg in your system PATH or in standard WinGet directories.

Install FFmpeg in one command via Windows Package Manager:

winget install Gyan.FFmpeg

Alternatively, download the official Windows build directly from gyan.dev/ffmpeg/builds (e.g. ffmpeg-release-essentials.zip) and add its bin folder to your system PATH.

Add the JitPack repository and the dependencies to your pom.xml:

<repositories>
    <repository>
        <id>jitpack.io</id>
        <url>https://jitpack.io</url>
    </repository>
</repositories>

<dependencies>
    <!-- FastScreenCapture Engine -->
    <dependency>
        <groupId>com.github.andrestubbe</groupId>
        <artifactId>FastScreenCapture</artifactId>
        <version>0.1.1</version>
    </dependency>

    <!-- Underlying Native & Zero-Copy Hardware Engines -->
    <dependency>
        <groupId>com.github.andrestubbe</groupId>
        <artifactId>FastScreen</artifactId>
        <version>0.1.4</version>
    </dependency>
    <dependency>
        <groupId>com.github.andrestubbe</groupId>
        <artifactId>fasthotkey</artifactId>
        <version>0.1.0</version>
    </dependency>
    <dependency>
        <groupId>com.github.andrestubbe</groupId>
        <artifactId>FastImage</artifactId>
        <version>0.1.4</version>
    </dependency>
    <dependency>
        <groupId>com.github.andrestubbe</groupId>
        <artifactId>FastSIMD</artifactId>
        <version>0.1.3</version>
    </dependency>
    <dependency>
        <groupId>com.github.andrestubbe</groupId>
        <artifactId>FastMemory</artifactId>
        <version>0.1.1</version>
    </dependency>
    <dependency>
        <groupId>com.github.andrestubbe</groupId>
        <artifactId>FastPointer</artifactId>
        <version>0.1.1</version>
    </dependency>
    <dependency>
        <groupId>com.github.andrestubbe</groupId>
        <artifactId>FastCore</artifactId>
        <version>0.1.0</version>
    </dependency>
</dependencies>

repositories {
    maven { url 'https://jitpack.io' }
}

dependencies {
    implementation 'com.github.andrestubbe:FastScreenCapture:0.1.1'
    implementation 'com.github.andrestubbe:FastScreen:0.1.4'
    implementation 'com.github.andrestubbe:fasthotkey:0.1.0'
    implementation 'com.github.andrestubbe:FastImage:0.1.4'
    implementation 'com.github.andrestubbe:FastSIMD:0.1.3'
    implementation 'com.github.andrestubbe:FastMemory:0.1.1'
    implementation 'com.github.andrestubbe:FastPointer:0.1.1'
    implementation 'com.github.andrestubbe:FastCore:0.1.0'
}

1. 📸 FastScreenCapture-0.1.1.jar (The CLI & Capture Engine)
2. 🖥️ FastScreen-0.1.4.jar (DirectX 11 DXGI Desktop Capture & Native Engine)
3. ⌨️ FastHotkey-0.1.0.jar (Low-Latency Win32 System Hotkeys)
4. 🖼️ FastImage-0.1.4.jar (Zero-Copy Frame Container & SIMD Filters)
5. ⚡ FastSIMD-0.1.3.jar (Vectorized SIMD Math Core)
6. 🧠 FastMemory-0.1.1.jar (High-Performance Off-Heap Memory Manager)
7. 📍 FastPointer-0.1.1.jar (Zero-Overhead Direct Memory Pointer Bridge)
8. ⚙️ FastCore-0.1.0.jar (Mandatory Native Library & DLL Auto-Loader)

• PHILOSOPHY.md: The engineering rationale for uncompressed zero-latency captures.
• REFERENCE.md: Complete CLI switches and Java API reference.
• CHANGELOG.md: Full release history and version notes.
• ROADMAP.md: Upcoming features, 60+ FPS video streaming, and ecosystem milestones.

MIT License — See LICENSE for details.

• FastScreen — Ultra-Fast DirectX Screen Capture Engine
• FastAnimation — High-Performance Zero-GC 60/120 FPS Animation Engine
• FastCamera — Hardware-Accelerated Native Camera Capture & Streaming
• FastHotkey — Low-Latency Global System Hotkeys
• FastImage — SIMD-Accelerated Off-Heap Image Engine
• FastDWM — Native Windows Desktop Window Manager & VSync Engine
• FastSIMD — AVX2/AVX-512 Vectorized Math Acceleration
• FastPointer — Safe Zero-Overhead Direct Memory Pointer Bridge
• FastMemory — High-Performance Off-Heap Memory Buffers
• FastCore — Native Library Loader for Java

Part of the FastJava Ecosystem — Making the JVM faster. ⚡