Multimedia
Introduction
The multimedia subsystem provides a set of simple and easy-to-use APIs for you to access the system and media resources.
This subsystem offers various media services covering audio, videos, and cameras, which provide the following capabilities:
-
Audio playback and recording
-
Video playback and recording
-
Photographing and recording (with cameras)
Architecture
Figure 1 Common architecture of the multimedia subsystem
Figure 2 Architecture of the multimedia subsystem suitable for the small system
Figure 3 Multimedia service flow for the small system
Directory Structure
The structure of the repository directory is as follows:
/foundation/multimedia # Service code
├── audio_lite # Audio module for the small system
│ ├── figures # Architecture and process figures of the audio module for the small system
│ ├── frameworks # Audio framework implementation for the small system
│ └── interfaces # Audio module APIs for the small system
├── audio_standard # Audio module for the standard system
│ ├── figures # Architecture and process figures of the audio module for the standard system
│ ├── frameworks # Audio framework implementation for the standard system
│ ├── interfaces # Audio module APIs for the standard system
│ ├── sa_profile # Audio service profile for the standard system
│ └── services # Audio service implementation for the standard system
├── camera_lite # Camera module for the small system
│ ├── figures # Architecture and process figures of the camera module for the small system
│ ├── frameworks # Camera framework implementation for the small system
│ └── interfaces # Camera module APIs for the small system
├── camera_standard # Camera module for the standard system
│ ├── figures # Architecture and process figures of the camera module for the standard system
│ ├── frameworks # Camera framework implementation for the standard system
│ └── interfaces # Camera module APIs for the standard system
├── media_lite # Playback and recording module for the small system
│ ├── figures # Architecture and process figures of the playback and recording module for the small system
│ ├── frameworks # Playback and recording framework implementation for the small system
│ ├── interfaces # Playback and recording module APIs for the small system
│ └── services # Playback and recording service implementation for the small system
├── media_standard # Playback and recording module for the standard system
│ ├── figures # Architecture and process figures of the playback and recording module for the standard system
│ ├── frameworks # Playback and recording framework implementation for the standard system
│ └── interfaces # Playback and recording module APIs for the standard system
└── utils # Subsystem utility module
└── lite # Utility module for the small system
├── figures # Architecture and process figures of the utility module for the small system
├── hals # Hardware abstraction interfaces of the subsystem for the small system
├── interfaces # Utility module APIs for the standard system
└── src # Utility module framework implementation for the small system
Constraints
Hardware-based decoding and encoding functions of audio and video data are device-specific.
Usage Guidelines
You can use the APIs in any of the provided classes based on your development requirements.
- For details about how to call media APIs to implement the video recording, preview, and playback, see Multimedia Development Guide.
- For a simple player, use Player and Recorder classes to quickly implement the playback and recording features.
- The CameraKit class provides a group of effective methods for controlling a camera, which facilitates the camera development.
- You can create a CameraKit object and register various callbacks to respond to many events in the multimedia module. Then, create a Camera object to operate camera resources, for example, to start preview, recording, and stream capturing, and set related parameters.
Installation
Load the kernel and related drivers before installing the repository. For details, see readme files of kernel and driver subsystems.