Voice SDK for Android
- API Overview
  Agora provides ensured quality of experience (QoE) for worldwide Internet-based voice and video communications through SD-RTN™.
- Lite SDK API List
  This page lists the APIs supported by Lite SDK.
- RtcEngine
  The basic interface of the Agora SDK that implements the core functions of real-time communication.
- RtcEngineEx
  This interface class contains multi-channel methods.
- IRtcEngineEventHandler
  The SDK uses the IRtcEngineEventHandler interface to send event notifications to your app. Your app can get those notifications through methods that inherit this interface.
- IAudioEffectManager
  This class provides audio management methods.
- IAudioEncodedFrameObserver
  The encoded audio observer.
- IMediaExtensionObserver
  Extension event callback interface class.
- IMediaPlayer
  This class provides media player functions and supports multiple instances.
- IMediaPlayerAudioFrameObserver
  The audio frame observer for the media player.
- IMediaPlayerCacheManager
  This class provides methods to manage cached media files.
- IMediaPlayerCustomDataProvider
  The callback for custom media resource files.
- IMediaPlayerObserver
  Provides callbacks for media players.
- IMediaPlayerVideoFrameObserver
  The video frame observer for the media player.
- IAudioFrameObserver
  The audio frame observer.
- IMediaEngine
  The IMediaEngine class.
- IFaceInfoObserver
  Facial information observer.
- IAudioSpectrumObserver
  The audio spectrum observer.
- IMetadataObserver
  The metadata observer.
- IVideoEncodedFrameObserver
  Receives encoded video images.
- IVideoFrameObserver
  The IVideoFrameObserver class.
- ILocalSpatialAudioEngine
  This class calculates user positions through the SDK to implement the spatial audio effect.
- Class and Enum
  This page lists all the definitions of Class and the enums for Android.
- API Sunset Notice
  This page introduces the deprecated and deleted APIs in the SDK.

IMetadataObserver

The metadata observer.

You can call registerMediaMetadataObserver to register or unregister the IMetadataObserver object.

getMaxMetadataSize

Occurs when the SDK requests the maximum size of the metadata.

public abstract int getMaxMetadataSize();

After successfully complete the registration by calling registerMediaMetadataObserver, the SDK triggers this callback once every video frame is sent. You need to specify the maximum size of the metadata in the return value of this callback.

Returns

The maximum size of the buffer of the metadata that you want to use. The highest value is 1024 bytes. Ensure that you set the return value.

onMetadataReceived

Occurs when the local user receives the metadata.

public abstract void onMetadataReceived(AgoraMetadata metadata);

Parameters

metadata: The metadata received. See Metadata.

onReadyToSendMetadata

Occurs when the SDK is ready to send metadata.

public abstract byte[] onReadyToSendMetadata(long timeStampMs, int sourceType);

This callback is triggered when the SDK is ready to send metadata.

Attention: Ensure that the size of the metadata does not exceed the value set in the getMaxMetadataSize callback.

Parameters

timeStampMs: The timestamp.
sourceType: Video data type. See VideoSourceType.

Returns

The metadata that you want to send in the format of byte. Ensure that you set the return value.