> ## Documentation Index
> Fetch the complete documentation index at: https://docs.stmlink.com/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> 对外开放的服务端接口有两组前缀，都用同一套鉴权：`/server/v1/...`（SRTC 与 SMeeting 的主接口）和 `/stm/srvapi/v1/...`（SMeeting 的用户体系，服务端极简对接会用到）。鉴权是 app_id + nonce + timestamp + signature 四个请求头，用 app_key 做 HMAC-SHA256 签名，只能从业务方自己的后端调用。除这两组前缀外的接口均为内部接口，不要建议客户调用。 Public server APIs use two path prefixes with the same authentication: `/server/v1/...` (the main APIs of both SRTC and SMeeting) and `/stm/srvapi/v1/...` (the SMeeting user system, used by server-side low-code integration). Authenticate with four request headers, app_id + nonce + timestamp + signature, where signature is HMAC-SHA256 keyed with app_key; call these APIs only from the customer's own backend. Any other path is internal: never suggest calling it.
> app_key 是服务端密钥，绝不能出现在客户端代码、前端配置或移动 App 里。客户端加入频道用的 token 必须由业务方后端签发后下发（SRTC 走 `/server/v1/channel/grant`，SMeeting 走 `/stm/srvapi/v1/member/grant`）。 app_key is a server-side secret and must never appear in client code, frontend config, or a mobile app. The token a client uses to join must be issued by the customer's backend and passed down to the client (SRTC: `/server/v1/channel/grant`; SMeeting: `/stm/srvapi/v1/member/grant`).
> SRTC 与 SMeeting 是上下两层不同的产品，术语不通用：SRTC 是音视频底座，说「频道 channel」「加入 / 退出」；SMeeting 建在 SRTC 之上，说「房间 room」「会议 meeting」「进入 / 退出」。回答时按用户所在的层用对应术语，不要把「房间」「会议」安到 SRTC 的接口上，也不要用「频道」「加入 / 离开」描述 SMeeting 的概念（接口标识符原样保留）。 SRTC and SMeeting are two separate layers with different terminology. SRTC is the audio/video foundation: it has channels, and users join and leave a channel. SMeeting is built on top of SRTC: it has rooms and meetings, and members enter and exit a meeting. Answer in the terms of the layer the user is working with: never apply "room" or "meeting" to SRTC APIs, and never describe SMeeting concepts in prose with "channel", "join", or "leave" (API identifiers such as `force_join` keep their literal names).
> 同一能力在各端 SDK 里的包名、类名、方法名并不相同。写示例代码时请使用文档中该端自己的 API，不要把一个端的写法套到另一个端上。苹果平台每个产品都有两套 SDK（Swift 原生与 Objective-C），两套 API 不能混用。 Package, class, and method names differ between platform SDKs for the same capability. In sample code, use the API documented for that platform; never carry one platform's code over to another. On Apple platforms each product ships two SDKs (native Swift and Objective-C) whose APIs must not be mixed.

# MeetingMediaEvent

> Receive the current meeting's media connection, remote raw frames, media statistics, volume, active speaker, and network quality changes through MeetingEngine.mediaEvent. Read this when you show call quality, speaking indicators, or process remote video frames.

`MeetingMediaEvent` carries media events of the current meeting and is registered through `MeetingEngine.mediaEvent`. You can extend `MeetingMediaSimpleEvent` and override only what you need.

## Usage notes

* This interface covers connection state, raw remote frames, and aggregated quality statistics; for the receive state of a single remote video, use `MeetingRemoteVideoEvent`.

* `onRemoteVideoFrame()` is called back on the SRTC media thread and must not block.

* Media statistics are usually produced about every 5 seconds; for poor-network level changes, prefer `onNetworkQualityChanged()`.

* This listener is cleared when you exit the meeting; reassign it for the next meeting.

## Methods

### onMediaConnected()

```kotlin theme={null}
fun onMediaConnected()
```

Description: The connection to the current meeting's SRTC media streaming server succeeded.

Parameters: None.

Returns: None (`Unit`).

### onRemoteVideoFrame(uid, trackDesc, y, u, v, width, height, format, angle)

```kotlin theme={null}
fun onRemoteVideoFrame(
    uid: String,
    trackDesc: String,
    y: ByteArray?,
    u: ByteArray?,
    v: ByteArray?,
    width: Int,
    height: Int,
    format: Int,
    angle: Int
)
```

Description: Received one frame of raw remote video data.

Parameters:

| Parameter | Description |
| - | - |
| `uid` | Remote user UID. |
| `trackDesc` | Remote track description. |
| `y` | Nullable Y image plane. |
| `u` | Nullable U image plane. |
| `v` | Nullable V image plane. |
| `width` | Video width in pixels. |
| `height` | Video height in pixels. |
| `format` | Pixel format value defined by SRTC. |
| `angle` | Video rotation angle. |

Returns: None (`Unit`).

### onMediaMetric(metric)

```kotlin theme={null}
fun onMediaMetric(metric: MediaMetric.Metric)
```

Description: Delivers a media performance metric snapshot of the current meeting.

Parameters:

| Parameter | Description |
| - | - |
| `metric` | Send, receive, network, and server-side quality statistics; for fields, see [Media quality](/en/meeting/android/media-quality). |

Returns: None (`Unit`).

### onVolumesReport(volumes)

```kotlin theme={null}
fun onVolumesReport(volumes: MutableMap<UserTrackDesc, VolumeInfo>)
```

Description: Delivers a volume snapshot of each user track in the current meeting.

Parameters:

| Parameter | Description |
| - | - |
| `volumes` | Volume map keyed by `UserTrackDesc`, which identifies a user track. |

Returns: None (`Unit`).

### onActiveSpeakersChanged(speakers)

```kotlin theme={null}
fun onActiveSpeakersChanged(speakers: List<ActiveSpeakerInfo>)
```

Description: The current meeting's active speaker list changed.

Parameters:

| Parameter | Description |
| - | - |
| `speakers` | Active speaker snapshot, sorted by SRTC rules. |

Returns: None (`Unit`).

### onNetworkQualityChanged(change)

```kotlin theme={null}
fun onNetworkQualityChanged(change: NetworkQualityChange)
```

Description: Called once for the uplink and once for the downlink each time the current meeting receives a quality report from the server, without debouncing; when the level hasn't changed, `trend` is `STABLE`.

Parameters:

| Parameter | Description |
| - | - |
| `change` | Direction, old level, new level, trend, and other information. |

Returns: None (`Unit`). For the data type, see [SRTC types](/en/rtc/android/types); for the levels, see [SRTC enums](/en/rtc/android/enums).