The `c_mpos/src/webcam.c` module provides webcam support for desktop builds using the V4L2 API.

**Resolution Adaptation**:

- Automatically queries supported YUYV resolutions from the webcam using V4L2 API

- Supports all 23 ESP32 camera resolutions via intelligent cropping/padding

- **Center cropping**: When requesting smaller than available (e.g., 240x240 from 320x240)

- **Black border padding**: When requesting larger than maximum supported

- Always returns exactly the requested dimensions for API consistency

**Behavior**:

- On first init, queries device for supported resolutions using `VIDIOC_ENUM_FRAMESIZES`

- Selects smallest capture resolution ≥ requested dimensions (minimizes memory/bandwidth)

- Converts YUYV to RGB565 (color) or grayscale during capture

- Caches supported resolutions to avoid re-querying device

**Examples**:

*Cropping (common case)*:

- Request: 240x240 (not natively supported)

- Capture: 320x240 (nearest supported YUYV resolution)

- Process: Extract center 240x240 region

- Result: 240x240 frame with centered content

*Padding (rare case)*:

- Request: 1920x1080

- Capture: 1280x720 (webcam maximum)

- Process: Center 1280x720 content in 1920x1080 buffer with black borders

- Result: 1920x1080 frame (API contract maintained)

**Performance**:

- Exact matches use fast path (no cropping overhead)

- Cropped resolutions add ~5-10% CPU overhead

- Padded resolutions add ~3-5% CPU overhead (memset + center placement)

- V4L2 buffers sized for capture resolution, conversion buffers sized for output

**Implementation Details**:

- YUYV format: 2 pixels per macropixel (4 bytes: Y0 U Y1 V)

- Crop offsets must be even for proper YUYV alignment

- Center crop formula: `offset = (capture_dim - output_dim) / 2`, then align to even

- Supported resolutions cached in `supported_resolutions_t` structure

- Separate tracking of `capture_width/height` (from V4L2) vs `output_width/height` (user requested)

**File Location**: `c_mpos/src/webcam.c` (C extension module)