# StartComposition
Starts a Composition from a stage based on the configuration provided in the request.
A Composition is an ephemeral resource that exists after this operation returns successfully. Composition stops and the resource is deleted:
+ When [StopComposition](API_StopComposition.md) is called.
+ After a 1-minute timeout, when all participants are disconnected from the stage.
+ After a 1-minute timeout, if there are no participants in the stage when StartComposition is called.
+ When broadcasting to the IVS channel fails and all retries are exhausted.
+ When broadcasting is disconnected and all attempts to reconnect are exhausted.
## Request Syntax
```
POST /StartComposition HTTP/1.1
Content-type: application/json
{
"destinations": [
{
"channel": {
"channelArn": "string",
"encoderConfigurationArn": "string"
},
"name": "string",
"s3": {
"encoderConfigurationArns": [ "string" ],
"recordingConfiguration": {
"format": "string",
"hlsConfiguration": {
"targetSegmentDurationSeconds": number
}
},
"storageConfigurationArn": "string",
"thumbnailConfigurations": [
{
"storage": [ "string" ],
"targetIntervalSeconds": number
}
]
}
}
],
"idempotencyToken": "string",
"layout": {
"grid": {
"featuredParticipantAttribute": "string",
"gridGap": number,
"omitStoppedVideo": boolean,
"participantOrderAttribute": "string",
"videoAspectRatio": "string",
"videoFillMode": "string"
},
"pip": {
"featuredParticipantAttribute": "string",
"gridGap": number,
"omitStoppedVideo": boolean,
"participantOrderAttribute": "string",
"pipBehavior": "string",
"pipHeight": number,
"pipOffset": number,
"pipParticipantAttribute": "string",
"pipPosition": "string",
"pipWidth": number,
"videoFillMode": "string"
}
},
"stageArn": "string",
"tags": {
"string" : "string"
}
}
```
## URI Request Parameters
The request does not use any URI parameters.
## Request Body
The request accepts the following data in JSON format.
** [destinations](#API_StartComposition_RequestSyntax) **
Array of destination configuration.
Type: Array of [DestinationConfiguration](API_DestinationConfiguration.md) objects
Array Members: Minimum number of 1 item. Maximum number of 2 items.
Required: Yes
** [idempotencyToken](#API_StartComposition_RequestSyntax) **
Idempotency token.
Type: String
Length Constraints: Minimum length of 1. Maximum length of 64.
Pattern: `[a-zA-Z0-9-_]*`
Required: No
** [layout](#API_StartComposition_RequestSyntax) **
Layout object to configure composition parameters.
Type: [LayoutConfiguration](API_LayoutConfiguration.md) object
Required: No
** [stageArn](#API_StartComposition_RequestSyntax) **
ARN of the stage to be used for compositing.
Type: String
Length Constraints: Minimum length of 1. Maximum length of 128.
Pattern: `arn:aws:ivs:[a-z0-9-]+:[0-9]+:stage/[a-zA-Z0-9-]+`
Required: Yes
** [tags](#API_StartComposition_RequestSyntax) **
Tags attached to the resource. Array of maps, each of the form `string:string (key:value)`. See [Best practices and strategies](https://docs.aws.amazon.com/tag-editor/latest/userguide/best-practices-and-strats.html) in *Tagging AWS Resources and Tag Editor* for details, including restrictions that apply to tags and "Tag naming limits and requirements"; Amazon IVS has no constraints on tags beyond what is documented there.
Type: String to string map
Map Entries: Minimum number of 0 items. Maximum number of 50 items.
Key Length Constraints: Minimum length of 1. Maximum length of 128.
Value Length Constraints: Minimum length of 0. Maximum length of 256.
Required: No
## Response Syntax
```
HTTP/1.1 200
Content-type: application/json
{
"composition": {
"arn": "string",
"destinations": [
{
"configuration": {
"channel": {
"channelArn": "string",
"encoderConfigurationArn": "string"
},
"name": "string",
"s3": {
"encoderConfigurationArns": [ "string" ],
"recordingConfiguration": {
"format": "string",
"hlsConfiguration": {
"targetSegmentDurationSeconds": number
}
},
"storageConfigurationArn": "string",
"thumbnailConfigurations": [
{
"storage": [ "string" ],
"targetIntervalSeconds": number
}
]
}
},
"detail": {
"s3": {
"recordingPrefix": "string"
}
},
"endTime": "string",
"id": "string",
"startTime": "string",
"state": "string"
}
],
"endTime": "string",
"layout": {
"grid": {
"featuredParticipantAttribute": "string",
"gridGap": number,
"omitStoppedVideo": boolean,
"participantOrderAttribute": "string",
"videoAspectRatio": "string",
"videoFillMode": "string"
},
"pip": {
"featuredParticipantAttribute": "string",
"gridGap": number,
"omitStoppedVideo": boolean,
"participantOrderAttribute": "string",
"pipBehavior": "string",
"pipHeight": number,
"pipOffset": number,
"pipParticipantAttribute": "string",
"pipPosition": "string",
"pipWidth": number,
"videoFillMode": "string"
}
},
"stageArn": "string",
"startTime": "string",
"state": "string",
"tags": {
"string" : "string"
}
}
}
```
## Response Elements
If the action is successful, the service sends back an HTTP 200 response.
The following data is returned in JSON format by the service.
** [composition](#API_StartComposition_ResponseSyntax) **
The Composition that was created.
Type: [Composition](API_Composition.md) object
## Errors
For information about the errors that are common to all actions, see [Common Error Types](CommonErrors.md).
** AccessDeniedException **
** exceptionMessage **
User does not have sufficient access to perform this action.
HTTP Status Code: 403
** ConflictException **
** exceptionMessage **
Updating or deleting a resource can cause an inconsistent state.
HTTP Status Code: 409
** InternalServerException **
** exceptionMessage **
Unexpected error during processing of request.
HTTP Status Code: 500
** PendingVerification **
** exceptionMessage **
Your account is pending verification.
HTTP Status Code: 403
** ResourceNotFoundException **
** exceptionMessage **
Request references a resource which does not exist.
HTTP Status Code: 404
** ServiceQuotaExceededException **
** exceptionMessage **
Request would cause a service quota to be exceeded.
HTTP Status Code: 402
** ValidationException **
** exceptionMessage **
The input fails to satisfy the constraints specified by an AWS service.
HTTP Status Code: 400
## See Also
For more information about using this API in one of the language-specific AWS SDKs, see the following:
+ [AWS Command Line Interface V2](https://docs.aws.amazon.com/goto/cli2/ivs-realtime-2020-07-14/StartComposition)
+ [AWS SDK for .NET V4](https://docs.aws.amazon.com/goto/DotNetSDKV4/ivs-realtime-2020-07-14/StartComposition)
+ [AWS SDK for C\$1\$1](https://docs.aws.amazon.com/goto/SdkForCpp/ivs-realtime-2020-07-14/StartComposition)
+ [AWS SDK for Go v2](https://docs.aws.amazon.com/goto/SdkForGoV2/ivs-realtime-2020-07-14/StartComposition)
+ [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/ivs-realtime-2020-07-14/StartComposition)
+ [AWS SDK for JavaScript V3](https://docs.aws.amazon.com/goto/SdkForJavaScriptV3/ivs-realtime-2020-07-14/StartComposition)
+ [AWS SDK for Kotlin](https://docs.aws.amazon.com/goto/SdkForKotlin/ivs-realtime-2020-07-14/StartComposition)
+ [AWS SDK for PHP V3](https://docs.aws.amazon.com/goto/SdkForPHPV3/ivs-realtime-2020-07-14/StartComposition)
+ [AWS SDK for Python](https://docs.aws.amazon.com/goto/boto3/ivs-realtime-2020-07-14/StartComposition)
+ [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/ivs-realtime-2020-07-14/StartComposition)