cap-camera

Cross-platform camera capture API that provides a unified interface across macOS (AVFoundation) and Windows (Media Foundation/DirectShow) backends. Offers simple yet low-level access to camera devices with consistent device enumeration, format negotiation, and callback-based frame capture.

Purpose

Provides a single, ergonomic API for camera capture that abstracts platform differences while maintaining access to native capabilities. Designed to handle the complexity of different camera ecosystems on macOS and Windows through platform-specific backends while exposing a consistent Rust interface.

Key Features

• Unified Device Enumeration: Single list_cameras() call returns all available cameras across platforms
• Cross-Platform Format Support: Consistent Format abstraction over native format representations
• Callback-Based Capture: Platform-agnostic frame delivery via closures
• Zero-Copy Frame Access: Direct access to camera frame buffers without additional memory allocation
• Native Backend Access: Direct access to underlying AVFoundation/Media Foundation objects when needed
• Memory Safety: RAII resource management with automatic cleanup on drop
• Chromium-Compatible Device Identification: Consistent device tracking across sessions on the same platform

Core APIs

Device Management

• list_cameras() - Enumerate all cameras with unified CameraInfo objects
• CameraInfo::model_id(), CameraInfo::display_name() - Cross-platform device metadata
• CameraInfo::formats() - Iterator over platform-normalized Format objects

Capture Pipeline

• CameraInfo::start_capturing(format, callback) - Begin capture with unified callback interface
• RecordingHandle::stop_capturing() - Stop capture session and cleanup resources
• CapturedFrame::native() - Access platform-specific frame data when needed

Format Processing

• Format::width(), Format::height(), Format::frame_rate() - Cross-platform format properties
• Format::native() - Direct access to underlying AVFoundation/Media Foundation format objects

Device Identification (ModelID)

The ModelID system provides device identification within each platform, modeled after Chromium's VideoCaptureDeviceDescriptor::model_id. It combines vendor ID (VID) and product ID (PID) to create a unique identifier that remains stable across sessions and system reboots on the same platform.

Architecture

Bridges macOS AVFoundation and Windows Media Foundation/DirectShow through a unified device enumeration and capture interface. Platform-specific modules (macos.rs, windows.rs) handle the underlying capture mechanics and expose them through common traits and callbacks, while the main library provides a consistent API surface that abstracts away platform differences without sacrificing access to native functionality when needed.