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Composition Hooks

Overview

The Twilio Composition Hooks REST API lets you automate the creation of Compositions. A Composition Hook is a template that specifies how Group Room video recordings should be composed. Using this API you will be able to:

  • Create and manage Composition Hooks.
  • Monitor the Compositions created by Hooks.

Composition Hooks work per-account (i.e. project). Hence, when a Group Room is completed, all enabled Composition Hooks in the account will be executed against that room recordings.

This API is located beneath of the following base URL:

https://video.twilio.com

Contents

URI Schemes

These are the URI schemes for the Composition Hooks REST API and the supported methods:

  • /v1/CompositionHooks
    • GET: Lists Composition Hook resources.
    • POST: Creates new Composition Hook resources.
  • /v1/CompositionHooks/{CompositionHookSid}
    • GET: Retrieves a Composition Hook instance.
    • POST: Updates a Composition Hook instance.
    • DELETE: Deletes a Composition Hook instance.

Composition Hook instance resource

The Composition Hook instance resource represents a template that specifies how Group Room recordings should be composed.

Resource URI

/v1/CompositionHooks/{CompositionHookSid}

Resource Properties

A Composition Hook Instance Resource has the following properties:

Resource Properties in REST API format
account_sid
sid<AC> Not PII

The SID of the Account that created the CompositionHook resource.

friendly_name
string Not PII

The string that you assigned to describe the resource. Can be up to 100 characters long and must be unique within the account.

enabled
boolean Not PII

Whether the CompositionHook is active. When true, the CompositionHook is triggered for every completed Group Room on the account. When false, the CompositionHook is never triggered.

date_created
date_time<iso8601> Not PII

The date and time in GMT when the resource was created specified in ISO 8601 format.

date_updated
date_time<iso8601>? Not PII

The date and time in GMT when the resource was last updated specified in ISO 8601 format.

sid
sid<HK> Not PII

The unique string that we created to identify the CompositionHook resource.

audio_sources
string[] PII MTL: 30 DAYS

The array of track names to include in the compositions created by the composition hook. A composition triggered by the composition hook includes all audio sources specified in audio_sources except those specified in audio_sources_excluded. The track names in this property can include an asterisk as a wild card character, which matches zero or more characters in a track name. For example, student* includes tracks named student as well as studentTeam. Please, be aware that either video_layout or audio_sources have to be provided to get a valid creation request

audio_sources_excluded
string[] PII MTL: 30 DAYS

The array of track names to exclude from the compositions created by the composition hook. A composition triggered by the composition hook includes all audio sources specified in audio_sources except for those specified in audio_sources_excluded. The track names in this property can include an asterisk as a wild card character, which matches zero or more characters in a track name. For example, student* excludes student as well as studentTeam. This parameter can also be empty.

video_layout

A JSON object that describes the video layout of the composition in terms of regions as specified in the HTTP POST request that created the CompositionHook resource. See POST Parameters for more information. Please, be aware that either video_layout or audio_sources have to be provided to get a valid creation request

resolution
string Not PII

The dimensions of the video image in pixels expressed as columns (width) and rows (height). The string's format is {width}x{height}, such as 640x480.

trim
boolean Not PII

Whether intervals with no media are clipped, as specified in the POST request that created the CompositionHook resource. Compositions with trim enabled are shorter when the Room is created and no Participant joins for a while as well as if all the Participants leave the room and join later, because those gaps will be removed. See Specifying Video Layouts for more info.

format
enum:format Not PII

The container format of the media files used by the compositions created by the composition hook. If mp4 or webm, audio_sources must have one or more tracks and/or a video_layout element must contain a valid video_sources list, otherwise an error occurs.

status_callback
url? Not PII

The URL we call using the status_callback_method to send status information to your application.

status_callback_method
http_method Not PII

The HTTP method we should use to call status_callback. Can be POST or GET and defaults to POST.

url
url Not PII

The absolute URL of the resource.

HTTP GET

Returns the single Composition Hook instance identified by {CompositionHookSid}.

HTTP POST

Updates the Composition Hook instance identified by {CompositionHookSid}. Be aware that partial updates are not supported. This means that when updating you must specify all the POST parameters, even for properties that don't change. Any optional parameter that is not explicitly specified will be reset (i.e. set to its default value)

The following parameters are supported:

Parameters in REST API format
sid
Path
post sid<HK> Not PII

The SID of the CompositionHook resource to update.

friendly_name
Required
post string Not PII

A descriptive string that you create to describe the resource. It can be up to 100 characters long and it must be unique within the account.

enabled
Optional
post boolean Not PII

Whether the composition hook is active. When true, the composition hook will be triggered for every completed Group Room in the account. When false, the composition hook never triggers.

video_layout
Optional
post object PII MTL: 30 DAYS

A JSON object that describes the video layout of the composition hook in terms of regions. See Specifying Video Layouts for more info.

audio_sources
Optional
post string[] PII MTL: 30 DAYS

An array of track names from the same group room to merge into the compositions created by the composition hook. Can include zero or more track names. A composition triggered by the composition hook includes all audio sources specified in audio_sources except those specified in audio_sources_excluded. The track names in this parameter can include an asterisk as a wild card character, which matches zero or more characters in a track name. For example, student* includes tracks named student as well as studentTeam.

audio_sources_excluded
Optional
post string[] PII MTL: 30 DAYS

An array of track names to exclude. A composition triggered by the composition hook includes all audio sources specified in audio_sources except for those specified in audio_sources_excluded. The track names in this parameter can include an asterisk as a wild card character, which matches zero or more characters in a track name. For example, student* excludes student as well as studentTeam. This parameter can also be empty.

trim
Optional
post boolean Not PII

Whether to clip the intervals where there is no active media in the compositions triggered by the composition hook. The default is true. Compositions with trim enabled are shorter when the Room is created and no Participant joins for a while as well as if all the Participants leave the room and join later, because those gaps will be removed. See Specifying Video Layouts for more info.

format
Optional
post ienum:format Not PII

The container format of the media files used by the compositions created by the composition hook. Can be: mp4 or webm and the default is webm. If mp4 or webm, audio_sources must have one or more tracks and/or a video_layout element must contain a valid video_sources list, otherwise an error occurs.

resolution
Optional
post string Not PII

A string that describes the columns (width) and rows (height) of the generated composed video in pixels. Defaults to 640x480. The string's format is {width}x{height} where:

  • 16 <= {width} <= 1280
  • 16 <= {height} <= 1280
  • {width} * {height} <= 921,600

Typical values are:

  • HD = 1280x720
  • PAL = 1024x576
  • VGA = 640x480
  • CIF = 320x240

Note that the resolution imposes an aspect ratio to the resulting composition. When the original video tracks are constrained by the aspect ratio, they are scaled to fit. See Specifying Video Layouts for more info.

status_callback
Optional
post url Not PII

The URL we should call using the status_callback_method to send status information to your application on every composition event. If not provided, status callback events will not be dispatched.

status_callback_method
Optional
post http_method Not PII

The HTTP method we should use to call status_callback. Can be: POST or GET and the default is POST.

The return value is a 200 OK if the request is accepted and executed successfully. Otherwise, a 4xx is returned with detailed information about the problem.

HTTP DELETE

Deletes the Composition Hook instance identified by {CompositionHookSid}.

The return value is a 204 NO CONTENT if the request is accepted and executed successfully. In this case, deletion is immediate.

Otherwise, a 4xx is returned with detailed information about the problem.

Composition Hooks list resource

Resource URI

/v1/CompositionHooks

HTTP POST

Creates a new Composition Hook and registers it so that Twilio can fire it whenever a Group Room is completed.

The return value is a 201 CREATED if the request is accepted and executed successfully. Otherwise, a 4xx is returned with detailed information about the problem.

Supported POST parameters

The following table shows all the parameters that can be specified when creating a new Composition Hook.

Parameters in REST API format
friendly_name
Required
post string Not PII

A descriptive string that you create to describe the resource. It can be up to 100 characters long and it must be unique within the account.

enabled
Optional
post boolean Not PII

Whether the composition hook is active. When true, the composition hook will be triggered for every completed Group Room in the account. When false, the composition hook will never be triggered.

video_layout
Optional
post object PII MTL: 30 DAYS

An object that describes the video layout of the composition hook in terms of regions. See Specifying Video Layouts for more info.

audio_sources
Optional
post string[] PII MTL: 30 DAYS

An array of track names from the same group room to merge into the compositions created by the composition hook. Can include zero or more track names. A composition triggered by the composition hook includes all audio sources specified in audio_sources except those specified in audio_sources_excluded. The track names in this parameter can include an asterisk as a wild card character, which matches zero or more characters in a track name. For example, student* includes tracks named student as well as studentTeam.

audio_sources_excluded
Optional
post string[] PII MTL: 30 DAYS

An array of track names to exclude. A composition triggered by the composition hook includes all audio sources specified in audio_sources except for those specified in audio_sources_excluded. The track names in this parameter can include an asterisk as a wild card character, which matches zero or more characters in a track name. For example, student* excludes student as well as studentTeam. This parameter can also be empty.

resolution
Optional
post string Not PII

A string that describes the columns (width) and rows (height) of the generated composed video in pixels. Defaults to 640x480. The string's format is {width}x{height} where:

  • 16 <= {width} <= 1280
  • 16 <= {height} <= 1280
  • {width} * {height} <= 921,600

Typical values are:

  • HD = 1280x720
  • PAL = 1024x576
  • VGA = 640x480
  • CIF = 320x240

Note that the resolution imposes an aspect ratio to the resulting composition. When the original video tracks are constrained by the aspect ratio, they are scaled to fit. See Specifying Video Layouts for more info.

format
Optional
post ienum:format Not PII

The container format of the media files used by the compositions created by the composition hook. Can be: mp4 or webm and the default is webm. If mp4 or webm, audio_sources must have one or more tracks and/or a video_layout element must contain a valid video_sources list, otherwise an error occurs.

status_callback
Optional
post url Not PII

The URL we should call using the status_callback_method to send status information to your application on every composition event. If not provided, status callback events will not be dispatched.

status_callback_method
Optional
post http_method Not PII

The HTTP method we should use to call status_callback. Can be: POST or GET and the default is POST.

trim
Optional
post boolean Not PII

Whether to clip the intervals where there is no active media in the Compositions triggered by the composition hook. The default is true. Compositions with trim enabled are shorter when the Room is created and no Participant joins for a while as well as if all the Participants leave the room and join later, because those gaps will be removed. See Specifying Video Layouts for more info.

Managing Video Layouts

A Composition Hook VideoLayout describes the video layout of compositions created by that Hook. Details on how to specify such a VideoLayout can be found in the Specifying Video Layouts section on Twilio's Compositions REST API documentation. The only aspect you may take into consideration is that, when working with Composition Hooks, you don't have information about the specific SIDs of tracks, recordings and participants. Hence, you must specify layouts basing on track names and set such names appropriately in your real-time Group Rooms.

HTTP GET

Retrieves the list Composition Hook Records belonging to the corresponding AccountSid with paging data.

Supported GET parameters

The following GET query string parameters allow you to limit the list returned. Note, parameters are case-sensitive

HTTP DELETE

Not Supported

Parameters in REST API format
enabled
Optional
get boolean Not PII

Read only CompositionHook resources with an enabled value that matches this parameter.

date_created_after
Optional
get date_time<iso8601> Not PII

Read only CompositionHook resources created on or after this ISO 8601 datetime with time zone.

date_created_before
Optional
get date_time<iso8601> Not PII

Read only CompositionHook resources created before this ISO 8601 datetime with time zone.

friendly_name
Optional
get string Not PII

Read only CompositionHook resources with friendly names that match this string. The match is not case sensitive and can include asterisk * characters as wildcard match.

Examples

Programming with Composition Hooks is quite similar to programming with Compositions. Hence, in addition to the examples here below, you may also find useful our Recording Compositions documentation

Creating an audio mixing Composition Hook

In this example we want to compose only the audio tracks of all completed Group Rooms. Considering that:

  • Your application credentials are (SKXXXX:your_api_key_secret)
  • You want to mix all audio tracks

The desired Composition Hook can be created with the following code:

        
        
        

        Creating a simple video mixing Composition Hook

        In this example we create a Composition Hook for composing all tracks of a Group Room using a simple grid layout for video.

        Considering that:

        • Your application credentials are (SKXXXX:your_api_key_secret)
        • You want to use mp4 as target format
        • You want to use VGA resolution (640x480)

        You can create the desired Composition Hook using the following:

              
              
              

              Creating a video mixing Composition Hook with complex layout

              In this example we create a Composition Hook that fires a composition with PiP (Picture-in-Picture) layout for every completed Group Room. Observe that, at Hook creation time we don't know any track or recording SIDs. Due to this, we must rely on track names. Here we assume that such names comply with the following:

              • A presenter must share a webcam track named presenter-cam as well as a screenshare track named screen. The presenter audio track, in turn, has the name presenter-audio.
              • In addition to the presenter, the room may have a special participant whose audio track we want to include in the composition. When that participant is present, her audio track has the name listener-audio.

              Assuming that:

              • Your application credentials are (SKXXXX:your_api_key_secret)
              • You want to use mp4 as target format
              • You want to use HD resolution (1280x720)

              The desired Composition Hook may be created as follows:

                    
                    
                    

                    Getting a Composition Hook

                    For executing this example you need:

                    • Your application credentials (SKXXXX:your_api_key_secret)
                    • The Composition Hook Sid (HKXXXX)
                          
                          
                          

                          Listing all enabled Composition Hooks

                          For executing this example you need:

                          • Your application credentials (SKXXXX:your_api_key_secret)
                                
                                
                                

                                Updating a Composition Hook

                                A very important aspect that you must remember is that we do not support partial updates. This means that you must provide all POST parameters on every update operation. In other words, any optional parameter you don't provide will be reset (i.e. set to its default value) with the update.

                                Just for illustration, the following example updates the above-created Grid Composition Hook to disable it. Observe that we need to provide again all the properties that were set during the create operation.

                                      
                                      
                                      

                                      Deleting a Composition Hook

                                      For executing this example you need:

                                      • Your application credentials (SKXXXX:your_api_key_secret)
                                      • The Composition Hook Sid (HKXXXX)
                                            
                                            
                                            

                                            Known Problems and Limitations

                                            There are no known problems.

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