update readme

README.md

@@ -5,4 +5,30 @@ are webcams and which are the additional metadata control handles.
 The list of strings returned are the full filepaths to valid devices.
 
 >[!IMPORTANT]
->In order for this library to work properly, the executing user must have either root or video group privileges 
+>In order for this library to work properly, the executing user must have either root or video group privileges
+
+## Technical Details
+
+The library works by:
+
+1. Scanning `/dev` for files matching the pattern `video*`
+2. Using the `VIDIOC_QUERYCAP` ioctl to check if each device is a video capture device
+3. Filtering out non-capture devices (like metadata control handles)
+
+The core functionality is implemented through direct syscalls to the Linux kernel's V4L2 (Video4Linux2) API. The library uses the `VIDIOC_QUERYCAP` ioctl command to query device capabilities and determine if a device supports video capture.
+
+## Usage
+
+```go
+devices, err := vidnumerator.EnumeratedVideoDevices()
+if err != nil {
+    // handle error
+}
+// devices will contain paths like "/dev/video0", "/dev/video2", etc.
+```
+
+## Implementation Notes
+
+- Uses direct syscalls via `golang.org/x/sys/unix`
+- Implements custom ioctl constants for V4L2 device querying
+- Checks for specific device capabilities (0x4200001) to identify capture devices