As an open source operating system, Android offers device and chip manufacturers hardware abstraction layers (HALs) to be implemented as interfaces for common mobile OS functions.
These HALs now come in the even more portable and persistent HAL interface definition language (HIDL). HIDL enables the framework to be replaced without rebuilding the HALs.
Audio
Android's audio HAL connects the higher-level, audio-specific framework APIs to the underlying audio driver and hardware.
Camera
The camera subsystem includes implementations for camera pipeline components while the camera HAL provides interfaces for use in implementing your version of these components.
Connectivity
This section describes implementation of standard Android connectivity protocols and describes use of related features, including Bluetooth, NFC, Wi-Fi, Telephony, and more.
Graphics
The Android framework offers a variety of graphics-rendering APIs for 2D and 3D that interact with manufacturer implementations of graphics drivers.
Interaction/Input
The Android interaction/input subsystem consists of an event pipeline that traverses multiple layers of the system and supports automotive, neural networks, peripherals, sensors, and TV.
Media
Android includes Stagefright, a media playback engine at the native level that has built-in software-based codecs for popular media formats.
Storage
All versions of Android support traditional storage with support for adoptable storage arriving in Android 6.0.