> ## 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. # SRTC > API reference for SRTC, the Web SDK's main entry class: constructor, joining and leaving channels, channel and user info, network quality queries, device enumeration, creating local tracks, publishing and subscribing, IM, event callbacks, and destroy. SRTC is the main entry point of the Web SDK. Create an instance with `new SRTC(initParams)`. The channel-level methods on this page (publishing, subscribing, user queries, `leave`, etc.) are **equivalent** to the methods of the same name on the Channel object returned by `join`, and act on the current (default) channel. When you join multiple channels at once, call them on each Channel object instead to specify the target. See [Multi-channel](/en/rtc/web/advanced/multi-channel). *** ### constructor ```typescript theme={null} constructor(initParams: SdkInitParams) ``` | Parameter | Type | Required | Description | | - | - | :-: | - | | `initParams` | `SdkInitParams` | Yes | Initialization parameters; see [SdkInitParams](/en/rtc/web/types#sdkinitparams) | *** ### buildInfo Gets the SDK build information. ```typescript theme={null} buildInfo(): BuildInfo ``` *** ### getEnvInfo Gets the WebRTC capability detection result for the current browser. We recommend calling it as early as possible after initialization. ```typescript theme={null} getEnvInfo(): EnvWebInfo ``` **Returns:** `EnvWebInfo`; see [EnvWebInfo](/en/rtc/web/types#envwebinfo) *** ### onNotifyChannelEvent In-channel event callback. We recommend registering it before `join`. ```typescript theme={null} onNotifyChannelEvent?: ((event: ChannelEvent) => void) | null ``` For the full list of event types, see [Events](/en/rtc/web/events). *** ### onNotifyImEvent Out-of-channel IM event callback. ```typescript theme={null} onNotifyImEvent?: ((event: ImEvent) => void) | null ``` *** ### join Joins a channel and returns that channel's **Channel object**. Get the channel info with `channel.getInfo()`. ```typescript theme={null} join(token: string, options?: JoinOptions): Promise ``` | Parameter | Type | Required | Description | | - | - | :-: | - | | `token` | `string` | Yes | Token for joining the channel, issued by the server | | `options` | `JoinOptions` | No | Join options; see [JoinOptions](/en/rtc/web/types#joinoptions) | You can call it multiple times to join several channels at once. Single-channel apps can ignore the return value and keep using the channel-level methods on the `srtc` instance (which act on the current channel). For the Channel object's methods and multi-channel usage, see [Multi-channel](/en/rtc/web/advanced/multi-channel). > Migrating from older versions: `join` used to return `ChannelInfo` and now returns a Channel object; the old return value is equivalent to `(await srtc.join(token)).getInfo()`. *** ### leave Leaves the channel. For local tracks, the SDK automatically stops capture, stops playback, or removes play views after leaving. ```typescript theme={null} leave(): Promise ``` With multiple channels, it acts on the earliest-joined channel and is equivalent to that channel's `channel.leave()`; to leave a specific channel, call `leave()` on its Channel object directly. *** ### getChannelInfo Gets the current channel info. Returns `null` when not in a channel. ```typescript theme={null} getChannelInfo(): ChannelInfo | null ``` *** ### getUserInfo Gets the info of a given user in the channel. ```typescript theme={null} getUserInfo(uid: string): UserInfo ``` | Parameter | Type | Required | Description | | - | - | :-: | - | | `uid` | `string` | Yes | User ID | *** ### getUsersInfo Gets the info of all users in the channel, as either an array or a map. ```typescript theme={null} getUsersInfo(map: true): Record getUsersInfo(map: false): UserInfo[] ``` *** ### getStreamMetric Gets the current full media metric snapshot, including overall network statistics and a `TrackMetric` for each local/remote track. ```typescript theme={null} getStreamMetric(): StreamMetric | undefined ``` > Throws if called when not in a channel. For field details, see [Network quality](/en/rtc/web/network-quality). *** ### getNetworkStats Gets the current overall network statistics. Use it when you only care about the network overview (bitrate, packet loss, RTT, available bandwidth); it's lighter than `getStreamMetric`. ```typescript theme={null} getNetworkStats(): NetworkStats | undefined ``` > Throws if called when not in a channel. *** ### getConnectionQuality Gets the current connection quality evaluation, returning the uplink/downlink levels, the overall level, MOS, and the triggering reasons. The SDK evaluates internally over a 2-second sliding window. ```typescript theme={null} getConnectionQuality(): QualityEvaluation | undefined ``` > Throws if called when not in a channel. For apps, we recommend subscribing to the `ChannelEventType.CONNECTION_QUALITY_CHANGED` event to be notified of changes passively. *** ### getDevices Enumerates media devices. ```typescript theme={null} getDevices(kind?: MediaDeviceKind, requestPermissions?: boolean): Promise ``` | Parameter | Type | Required | Description | | - | - | :-: | - | | `kind` | `'audioinput' \| 'audiooutput' \| 'videoinput'` | No | If omitted, devices of all types are returned | | `requestPermissions` | `boolean` | No | Whether to request media permissions proactively; defaults to `true` | *** ### createLocalMicTrack Creates a microphone audio track. ```typescript theme={null} createLocalMicTrack(preset?: MicPreset): LocalMicTrack ``` | Parameter | Type | Required | Description | | - | - | :-: | - | | `preset` | `MicPreset` | No | Microphone preset; defaults to `MicPresets.music` | *** ### createLocalCustomAudioTrack Creates a local audio track from a custom `MediaStreamTrack`. ```typescript theme={null} createLocalCustomAudioTrack(msTrack: MediaStreamTrack): LocalAudioTrack ``` | Parameter | Type | Required | Description | | - | - | :-: | - | | `msTrack` | `MediaStreamTrack` | Yes | An audio `MediaStreamTrack` | *** ### createLocalCameraTrack Creates a camera video track. ```typescript theme={null} createLocalCameraTrack(preset?: CameraPreset): LocalCameraTrack ``` | Parameter | Type | Required | Description | | - | - | :-: | - | | `preset` | `CameraPreset` | No | Camera preset; defaults to `CameraPresets['720p']` | *** ### createLocalScreenTrack Creates a screen sharing video track. ```typescript theme={null} createLocalScreenTrack(preset?: ScreenPreset, audioPreset?: ScreenAudioPreset): LocalScreenTrack ``` | Parameter | Type | Required | Description | | - | - | :-: | - | | `preset` | `ScreenPreset` | No | Video preset; defaults to `ScreenPresets['1080p']` | | `audioPreset` | `ScreenAudioPreset` | No | System audio preset; defaults to `ScreenAudioPresets.default` | > A system audio track is created as well by default. Whether system audio can actually be captured also depends on the browser's capabilities and on whether the user checks "Share audio" in the system sharing dialog. *** ### createLocalCustomVideoTrack Creates a local video track from a custom `MediaStreamTrack`. ```typescript theme={null} createLocalCustomVideoTrack(msTrack: MediaStreamTrack): LocalVideoTrack ``` | Parameter | Type | Required | Description | | - | - | :-: | - | | `msTrack` | `MediaStreamTrack` | Yes | A video `MediaStreamTrack` | *** ### createLocalCompositeRecorder Creates a local composite recorder, used in the browser to composite the video tiles and audio tracks that the current page needs to record into a local recording file. ```typescript theme={null} createLocalCompositeRecorder(): LocalCompositeRecorder ``` The returned `LocalCompositeRecorder` is only responsible for media compositing and the `MediaRecorder` lifecycle; your app computes the view—video grids, paging, speaker layout, screen sharing priority, and so on—and passes it in through `videoItems` and `updateVideoItems(...)`. > For detailed usage, see [Local recording](/en/rtc/web/advanced/local-recording). *** ### publishLocalTrack Publishes a local track to the channel; after publishing, remote users can subscribe to it. ```typescript theme={null} publishLocalTrack( track: LocalAudioTrack | LocalVideoTrack, opt?: Partial | Partial ): Promise ``` | Parameter | Type | Required | Description | | - | - | :-: | - | | `track` | `LocalAudioTrack \| LocalVideoTrack` | Yes | The local track to publish | | `opt` | `Partial \| Partial` | No | Publish parameters, merged with the preset parameters given when the track was created | **Returns:** `TrackInfo`, a snapshot of this publication's track description in the channel; to get the latest value later, use `channel.getPublishInfo(track)`. Within one channel, only one track per `desc` can be published. Publishing the same `desc` again with **a different** track (for example, a `mic` track is already published and you publish a second `mic`) throws; publishing the same track again is unaffected and remains idempotent. So serialize entry points such as turning on the microphone or camera yourself: if you publish again before the previous `publishLocalTrack` has finished awaiting, two tracks publish at the same time, and you usually only keep a reference to the one created later, so the one published first can never be unpublished. *** ### unpublishLocalTrack Unpublishes a local track; remote users receive the `USER_TRACK_REMOVE` event. ```typescript theme={null} unpublishLocalTrack(track: LocalAudioTrack | LocalVideoTrack): Promise ``` *** ### enableLocalTrack Resumes sending data for a paused local track. ```typescript theme={null} enableLocalTrack(track: LocalAudioTrack | LocalVideoTrack): Promise ``` > Remote users receive the `TRACK_UNMUTED` event. For how it differs from `publishLocalTrack`, see [Mute vs. unpublish](/en/rtc/web/advanced/mute-vs-unpublish). *** ### disableLocalTrack Pauses sending data for a local track without unpublishing it. ```typescript theme={null} disableLocalTrack(track: LocalAudioTrack | LocalVideoTrack): void ``` > Remote users receive the `TRACK_MUTED` event. For how it differs from `unpublishLocalTrack`, see [Mute vs. unpublish](/en/rtc/web/advanced/mute-vs-unpublish). *** ### subscribeRemoteAudioMixTrack Subscribes to the channel-wide mixed audio track. ```typescript theme={null} subscribeRemoteAudioMixTrack( filter?: string[] | ((track: BaseTrack) => boolean) ): Promise ``` | Parameter | Type | Required | Description | | - | - | :-: | - | | `filter` | `string[] \| ((track: BaseTrack) => boolean)` | No | Pass `string[]` to exclude by UID; pass a function to decide per track whether to filter it out | *** ### subscribeRemoteAudioTrack Subscribes to a single audio stream of a given user. ```typescript theme={null} subscribeRemoteAudioTrack(uid: string, id: string): Promise ``` | Parameter | Type | Required | Description | | - | - | :-: | - | | `uid` | `string` | Yes | User ID | | `id` | `string` | Yes | Track ID, available from `TrackInfo.id` | *** ### subscribeRemoteVideoTrack Subscribes to a given user's video stream. ```typescript theme={null} subscribeRemoteVideoTrack(uid: string, id: string): Promise ``` | Parameter | Type | Required | Description | | - | - | :-: | - | | `uid` | `string` | Yes | User ID | | `id` | `string` | Yes | Track ID, available from `TrackInfo.id` | *** ### subscribeRemoteVideoMcuTrack Subscribes to the remote composite video stream. ```typescript theme={null} subscribeRemoteVideoMcuTrack(): Promise ``` > `RemoteVideoMcuTrack` extends `RemoteVideoTrack` and can be used like a regular remote video track. *** ### unsubscribeRemoteTrack Unsubscribes from a remote stream. ```typescript theme={null} unsubscribeRemoteTrack( track: RemoteAudioMixTrack | RemoteAudioTrack | RemoteVideoTrack ): Promise ``` *** ### getRemoteTrack Gets a subscribed remote track instance by user ID and either track ID or track description. ```typescript theme={null} getRemoteTrack(uid: string, id?: string, desc?: string): RemoteAudioTrack | RemoteVideoTrack ``` | Parameter | Type | Required | Description | | - | - | :-: | - | | `uid` | `string` | Yes | User ID | | `id` | `string` | No | Track ID; pass either this or `desc` | | `desc` | `string` | No | Track description; pass either this or `id` | > You must pass at least one of `id` and `desc`; otherwise it throws. *** ### enableIm Enables out-of-channel IM messages. ```typescript theme={null} enableIm(token: string): Promise ``` | Parameter | Type | Required | Description | | - | - | :-: | - | | `token` | `string` | Yes | IM enable token | **Returns:** `Promise`, the IM session `sid`. *** ### disableIm Disables out-of-channel IM messages. ```typescript theme={null} disableIm(): Promise ``` *** ### destroy Fully releases the SRTC instance: leaves all channels in turn, disables IM, and removes the listeners the instance registered on browser global objects (device plug/unplug, page visibility). It's idempotent—repeated calls return immediately; calling the instance's methods afterward throws. ```typescript theme={null} destroy(): Promise ``` Without `destroy()`, the global listeners keep holding a reference to the instance so it can't be garbage-collected. So you **must call it** before an SPA route navigates away from the audio/video page, before a component unmounts, or before you create a new SRTC instance; apps whose instance lives as long as the page don't need to call it. For everyday joining and leaving of channels, `leave()` (or `channel.leave()`) is enough, and the instance can be reused to `join` again.