# Go FFmpeg WeChat Stream Demo

Standalone demo: Go finds the visible WeChat window, starts FFmpeg `avfoundation` screen capture, crops to the WeChat window rectangle, and serves an MJPEG stream locally.

If FFmpeg screen capture does not produce frames, the demo automatically falls back to macOS window-only capture with `screencapture -l <window_id>`. This captures the WeChat window itself, so other windows covering it should not appear in the stream.

Run:

```bash
cd demos/go-ffmpeg-wechat-stream
go run .
```

Open:

```text
http://127.0.0.1:8765/
```

Options:

```bash
go run . -input 3:none -fps 15 -port 8765 -open=true -wait=true
```

Notes:

- macOS only.
- Requires FFmpeg installed and available in `PATH`.
- Requires Screen Recording permission for the terminal/app running the demo.
- WeChat must be visible on screen.
- By default the demo waits until a visible WeChat window is found. Use `-wait=false` to fail immediately.
- FFmpeg `avfoundation` is screen-based, so crop mode can include windows covering WeChat. The fallback `screencapture -l` path is window-based and is closer to Tencent Meeting style app-window sharing.
- `-input` is the FFmpeg `avfoundation` screen device. List devices with:

```bash
ffmpeg -hide_banner -f avfoundation -list_devices true -i ""
```