# Windows Sender Demo

This is a simplified demo of the Windows Host sender for DisplayFlow.
It demonstrates:
1. Screen Capture using Desktop Duplication API (DXGI).
2. Hardware H.264 Encoding using Media Foundation (MF).
3. Network Transmission using UDP.

## Prerequisites

- Windows 10/11
- Visual Studio 2019 or later (with C++ Desktop Development)
- CMake 3.10+

## Build

1. Open a terminal (Developer Command Prompt for VS).
2. Navigate to this directory:
   ```cmd
   cd demo\windows_sender
   ```
3. Create a build directory:
   ```cmd
   mkdir build
   cd build
   ```
4. Configure and Build:
   ```cmd
   cmake ..
   cmake --build . --config Release
   ```

## Run

Run the executable with target IP and Port (optional):

```cmd
.\Release\WindowsSenderDemo.exe <TargetIP> <Port>
```

Example:
```cmd
.\Release\WindowsSenderDemo.exe 192.168.1.100 8888
```

## Implementation Details

- **ScreenCapture**: Uses `IDXGIOutputDuplication` to capture desktop frames.
- **VideoEncoder**: Uses `IMFTransform` (Media Foundation) to encode frames to H.264. 
  - *Note*: This demo attempts to feed RGB32 textures to the encoder. If the hardware encoder only supports NV12, conversion logic is needed (not fully implemented in this minimal demo).
- **NetworkSender**: Fragments the H.264 stream into UDP packets (MTU ~1400 bytes) and sends them to the target.

## Protocol

The demo uses a simple custom protocol for feasibility verification:
- **Packet Header** (Network Layer): `FrameID` (4B), `FragID` (2B), `TotalFrags` (2B).
- **Frame Header** (Application Layer, in first fragment/reassembled): `Timestamp` (8B), `Width` (4B), `Height` (4B), `Type` (4B), `Size` (4B).
- **Payload**: H.264 NAL units.