# TRTCTranscodingConfig class Null safety

On-Cloud MixTranscoding configuration

This contains the final encoding quality and the positions of images of each channel.

## Constructors

TRTCTranscodingConfig({int? appId, int? bizId, int mode = TRTCCloudDef.TRTC_TranscodingConfigMode_Unknown, int videoWidth = 0, int videoHeight = 0, int videoBitrate = 0, int videoFramerate = 15, int videoGOP = 2, int backgroundColor = 0x000000, String? backgroundImage, int audioSampleRate = 48000, int audioBitrate = 64, int audioChannels = 1, List<TRTCMixUser>? mixUsers, String? streamId})

## Properties

appId ↔ int?
  Field description: Tencent Cloud CSS `AppID` Recommended value: please select a created application in the TRTC console, click Application Info, and get it in "Relayed Live Streaming Info".
  read / write
audioBitrate ↔ int
  Field description: audio bitrate after transcoding. Recommended value: default value: 64 Kbps. Value range: `32,192`.
  read / write
audioChannels ↔ int
  Field description: number of sound channels after transcoding. Recommended value: default value: 1. Valid values: 1, 2.
  read / write
audioSampleRate ↔ int
  Field description: audio sample rate after transcoding. Recommended value: default value: 48000 Hz. Valid values: 12000 Hz, 16000 Hz, 22050 Hz, 24000 Hz, 32000 Hz, 44100 Hz, 48000 Hz.
  read / write
backgroundColor ↔ int
  Field description: background color of the mixed video image. The default value is black, and the format is hex number; for example: "0x61B9F1" represents the RGB color (97,158,241). Recommended value: default value: 0x000000 (black)
  read / write
backgroundImage ↔ String?
  Field description: background image of the mixed video image. Recommended value: default value: null, indicating not to set the background image Note: you need to upload the background image in "Application Management" > "Function Configuration" > "Material Management" in the console in advance.
  After the upload is successful, you can get the corresponding "image ID". Then, you need to convert it into a string and set it as `backgroundImage`.
  For example, if the "image ID" is 63, you can set `backgroundImage = "63"`;
  read / write
bizId ↔ int?
  Field description: Tencent Cloud CSS `bizid` Recommended value: please select a created application in the TRTC console, click Application Info, and get it in "Relayed Live Streaming Info".
  read / write
hashCode → int
  The hash code for this object.
  read-only, inherited
mixUsers ↔ List<TRTCMixUser>?
  Field description: position information of each channel of subimage
  read / write
mode ↔ int
  Field description: transcoding configuration mode
  read / write
runtimeType → Type
  A representation of the runtime type of the object.
  read-only, inherited
streamId ↔ String?
  Field description: ID of the live stream output to CDN If this parameter is not set, the SDK will execute the default logic, that is, it will mix the multiple streams in the room into the video stream of the caller of the API, i.e., A + B => A; If this parameter is set, the SDK will mix the multiple streams in the room into the live stream ID you specify, i.e., A + B => C. Recommended value: default value: null, that is, the multiple streams in the room will be mixed into the video stream of the caller of this API.
  read / write
videoBitrate ↔ int
  Field description: bitrate of video resolution in Kbps after transcoding. Recommended value: if you enter 0, the backend will estimate the bitrate based on `videoWidth` and `videoHeight`. You can also refer to the comment on the enumeration definition of `TRTC_VIDEO_RESOLUTION_640_480`.
  read / write
videoFramerate ↔ int
  Field description: frame rate of video resolution in fps after transcoding. Recommended value: default value: 15 fps. Value range: (0,30].
  read / write
videoGOP ↔ int
  Field description: keyframe interval (GOP) of video resolution after transcoding. Recommended value: default value: 2 (in seconds). Value range: `1,8`.
  read / write
videoHeight ↔ int
  Field description: height of video resolution after transcoding. Recommended value: 640 px. If you are pushing a pure audio stream, please set width x height to 0 px x 0 px; otherwise, a video stream with a canvas background will be carried after mixtranscoding.
  read / write
videoWidth ↔ int
  Field description: width of video resolution after transcoding. Recommended value: 360 px. If you are pushing a pure audio stream, please set width x height to 0 px x 0 px; otherwise, a video stream with a canvas background will be carried after mixtranscoding.
  read / write

## Methods

noSuchMethod(Invocation invocation) → dynamic
  Invoked when a non-existent method or property is accessed.
  inherited
toJson() → Map<String, dynamic>
toString() → String
  A string representation of this object.
  inherited

## Operators

operator ==(Object other) → bool
  The equality operator.
  inherited