# SimulcastStreamConfig (/zh-CN/api-reference/rtc/flutter/class-simulcaststreamconfig)

> For AI agents: see the complete documentation index at [llms.txt](/llms.txt).

<a id="class_simulcaststreamconfig__prototype"></a>

```dart
class SimulcastStreamConfig {
  const SimulcastStreamConfig({this.dimensions, this.kBitrate, this.framerate});

  @JsonKey(name: 'dimensions')
  final VideoDimensions? dimensions;
  @JsonKey(name: 'kBitrate')
  final int? kBitrate;
  @JsonKey(name: 'framerate')
  final int? framerate;
  factory SimulcastStreamConfig.fromJson(Map<String, dynamic> json) =>
      _$SimulcastStreamConfigFromJson(json);
  Map<String, dynamic> toJson() => _$SimulcastStreamConfigToJson(this);
}
```

<a id="class_simulcaststreamconfig__parameters"></a>

## 属性 [#属性]

<ParameterList>
<a id="dimensions"></a>
<Parameter name="dimensions">

视频尺寸。详见 [VideoDimensions](/zh-CN/api-reference/rtc/flutter/class-videodimensions)。默认值为视频大流的 50%。

</Parameter>
<a id="kbitrate"></a>
<Parameter name="kBitrate">

视频码率 (Kbps)，默认值为 -1。该参数无需设置，SDK 会根据你设定的视频分辨率和帧率自动匹配最合适的码率。

</Parameter>
<a id="framerate"></a>
<Parameter name="framerate">

视频帧率 (fps)。默认值为 5。

</Parameter>
</ParameterList>