82 lines
2.6 KiB
Markdown
82 lines
2.6 KiB
Markdown
# Windows Sender Demo
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This is a simplified demo of the Windows Host sender for DisplayFlow.
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It demonstrates:
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1. Screen Capture using Desktop Duplication API (DXGI).
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2. Hardware/Software H.264 Encoding using **FFmpeg** (switched from Media Foundation for better compatibility).
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3. Network Transmission using UDP.
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## Prerequisites
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- Windows 10/11
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- Visual Studio 2022 or later (with C++ Desktop Development)
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- CMake 3.10+
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- **FFmpeg Development Libraries** (Shared)
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- Ensure you have the `include` and `lib` directories.
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- Example path: `D:\tools\ffmpeg-8.0.1-full_build-shared`
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## Build
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1. Open a terminal (Developer Command Prompt for VS or PowerShell).
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2. Navigate to this directory:
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```cmd
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cd demo\windows_sender
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```
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3. Create a build directory:
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```cmd
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mkdir build
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cd build
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```
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4. Configure and Build (Replace path with your FFmpeg location):
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```cmd
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cmake .. -DFFMPEG_ROOT="D:/tools/ffmpeg-8.0.1-full_build-shared"
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cmake --build . --config Release
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```
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*Note: If your FFmpeg is installed elsewhere, change the path accordingly.*
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5. **Important**: Copy FFmpeg DLLs to the executable directory.
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- Copy `avcodec-*.dll`, `avutil-*.dll`, `swscale-*.dll`, `avformat-*.dll` from your FFmpeg `bin` directory to `demo\windows_sender\build\Release`.
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## Run
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Run the executable with optional arguments: Target IP, Port, and Output File.
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```cmd
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.\Release\WindowsSenderDemo.exe [TargetIP] [Port] [OutputFile]
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```
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### Examples
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1. **Basic Streaming** (Default: 127.0.0.1:8888):
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```cmd
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.\Release\WindowsSenderDemo.exe
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```
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2. **Specify Target**:
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```cmd
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.\Release\WindowsSenderDemo.exe 192.168.1.100 8888
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```
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3. **Stream and Save to File** (for debugging):
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```cmd
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.\Release\WindowsSenderDemo.exe 127.0.0.1 8888 debug.h264
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```
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You can play the saved `debug.h264` using VLC player to verify the encoding quality.
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## Implementation Details
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- **ScreenCapture**: Uses `IDXGIOutputDuplication` to capture desktop frames.
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- **VideoEncoder**:
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- Uses **FFmpeg (libx264)** for encoding.
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- Performs **BGRA to YUV420P** color conversion using `libswscale`.
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- Configured for low latency (`zerolatency` tune, `ultrafast` preset).
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- **NetworkSender**: Fragments the H.264 stream into UDP packets (MTU ~1400 bytes) and sends them to the target.
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## Protocol
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The demo uses a simple custom protocol for feasibility verification:
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- **Packet Header** (Network Layer): `FrameID` (4B), `FragID` (2B), `TotalFrags` (2B).
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- **Frame Header** (Application Layer, in first fragment/reassembled): `Timestamp` (8B), `Width` (4B), `Height` (4B), `Type` (4B), `Size` (4B).
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- **Payload**: H.264 NAL units.
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