Workflow Operation Handler

Introduction

Workflows are the central element to define how a media package is being processed by the Opencast services. Their definitions consist of a list of workflow operations, which basically map a piece of configuration to Opencast code:

<definition xmlns="http://workflow.opencastproject.org">
    ....
    <operation
      id="tag"
      <configurations>
        <configuration key="source-flavors">presentation/trimmed</configuration>
        <configuration key="target-flavor">presentation/tagged</configuration>
      </configurations>
   </operation>
   ...
</definition>

Default Workflow Operations

The following table contains the workflow operations that are available in an out-of-the-box Opencast installation:

Operation Handler	Description	Details
add-catalog	Add a catalog to the media package	Documentation
analyze-audio	Analyze first audio stream	Documentation
analyze-tracks	Analyze tracks in media package	Documentation
analyze-mediapackage	Analyze media package	Documentation
animate	Create animated video sequence	Documentation
amberscript-start-transcription	Start AmberScript Transcription	Documentation
amberscript-attach-transcription	Attach AmberScript Transcription	Documentation
assert	Verify preconditions with assertion	Documentation
asset-delete	Deletes the current mediapackage from the Archive	Documentation
attach-watson-transcription	Attaches automated transcripts to mediapackage	Documentation
cleanup	Cleanup the working file repository	Documentation
clone	Clone media package elements to another flavor	Documentation
comment	Add, resolve or delete a comment	Documentation
composite	Compose two videos on one canvas.	Documentation
concat	Concatenate multiple video tracks into one video track	Documentation
conditional-config	Configure workflow configuration variable based on coditions	Documentation
configure-by-dcterm	Set workflow parameter if dublincore term matches value	Documentation
copy	Copy media package elements to target directory	Documentation
cover-image	Generate a cover-image containing metadata	Documentation
crop-video	Checks for black bars on the sides of the video	Documentation
cut-marks-to-smil	Parses timestamps into a SMIL for the editor workflow	Documentation
defaults	Applies default workflow configuration values	Documentation
demux	Demuxes streams to multiple output files	Documentation
duplicate-event	Create an event by cloning an existing one	Documentation
editor	Waiting for user to review, then cut video based on edit-list	Documentation
encode	Encode media files to differents formats in parallel	Documentation
error-resolution	Internal operation to pause a workflow in error	Documentation
execute-many	Execute a command for each matching element in a MediaPackage	Documentation
execute-once	Execute a command for a MediaPackage	Documentation
export-wf-properties	Export workflow properties	Documentation
extract-text	Extracting text from presentation segments	Documentation
google-speech-attach-transcription	Attaches automated transcripts to mediapackage	Documentation
google-speech-start-transcription	Starts automated transcription provided by Google Speech	Documentation
http-notify	Notifies an HTTP endpoint about the process of the workflow	Documentation
image	Extract images from a video using FFmpeg	Documentation
image-convert	Convert images using FFmpeg	Documentation
image-to-video	Create a video track from a source image	Documentation
import-wf-properties	Import workflow properties	Documentation
incident	Testing incidents on a dummy job	Documentation
include	Include workflow definition in current workflow	Documentation
ingest-download	Download files from external URL for ingest	Documentation
inspect	Inspect the media (check if it is valid)	Documentation
log	Log workflow status	Documentation
mattermost-notify	Send messages to Mattermost	Documentation
metadata-to-acl	Add read/write access based on metadata	Documentation
microsoft-azure-attach-transcription	Attaches automated transcripts to mediapackage	Documentation
microsoft-azure-start-transcription	Starts automated transcription provided by Microsoft Azure	Documentation
move-storage	Move files between asset manager storage systems	Documentation
multiencode	Encode to multiple profiles in one operation	Documentation
normalize-audio	Normalize first audio stream	Documentation
partial-import	Import partial tracks and process according to a SMIL document	Documentation
post-mediapackage	Send mediapackage to remote service	Documentation
prepare-av	Preparing audio and video work versions	Documentation
probe-resolution	Set workflow instance variables based on video resolution	Documentation
process-smil	Edit and Encode media defined by a SMIL file	Documentation
publication-to-workspace	Copy publication element to mediapackage in workspace	Documentation
publish-configure-aws	Distribute and publish media to the configured publication using Amazon S3 and Cloudfront	Documentation
publish-configure	Distribute and publish media to the configured publication	Documentation
publish-engage-aws	Distribute and publish media to the engage player using Amazon S3 and Cloudfront	Documentation
publish-engage	Distribute and publish media to the engage player	Documentation
publish-oaipmh	Distribute and publish media to a OAI-PMH repository	Documentation
publish-youtube	Distribute and publish media to YouTube	Documentation
rename-files	Rename media files using metadata	Documentation
republish-oaipmh	Update media in a OAI-PMH repository	Documentation
retract-configure-aws	Retracts media from configured publication in AWS S3 and Cloudfront	Documentation
retract-configure	Retracts media from configured publication	Documentation
retract-engage-aws	Retracts media from AWS S3 and Cloudfront publication	Documentation
retract-engage	Retracts media from Opencast Media Module publication	Documentation
retract-partial-aws	Retract a subset of the mediapackage from a publication in Amazon S3 and Cloudfront	Documentation
retract-partial	Retract a subset of the mediapackage from a publication	Documentation
retract-oaipmh	Retracts media from a OAI-PMH repository	Documentation
retract-partial	Retract a subset of the mediapackage from a publication	Documentation
retract-youtube	Retracts media from YouTube	Documentation
sanitize-adaptive	Fix references to media files in a playlist	Documentation
segment-video	Extracting segments from presentation	Documentation
segmentpreviews	Extract segment images from a video using FFmpeg	Documentation
select-streams	Select streams for further processing	Documentation
select-version	Select a version of the media package to run the current workflow with	Documentation
send-email	Sends email notifications at any part of a workflow	Documentation
series	Apply series to the mediapackage	Documentation
silence	Silence detection on audio of the mediapackage	Documentation
snapshot	Archive the current state of the mediapackage	Documentation
speechtotext	Create subtitles for video and audio sources	Documentation
start-watson-transcription	Starts automated transcription provided by IBM Watson	Documentation
start-workflow	Start a new workflow for given media package ID	Documentation
statistics-writer	Log statistical data about the video	Documentation
tag	Modify the tag sets of media package elements	Documentation
tag-by-dcterm	Modify the tags if dublincore term matches value	Documentation
tag-engage	Modify the tag sets of media package elements in the engage publication	Documentation
theme	Make settings of themes available to processing	Documentation
timelinepreviews	Create a preview image stream from a given video track	Documentation
transfer-metadata	Transfer metadata fields between catalogs	Documentation
video-grid	Put parallel video streams on a single video canvas	Documentation
waveform	Create a waveform image of the audio of the mediapackage	Documentation
webvtt-to-cutmarks	Create cutting suggestions from subtitles	Documentation
zip	Create zipped archive of the current state of the mediapackage	Documentation

State Mappings

Technically, a workflow can be in one of the following states:

Technical State	Description	What the Admin UI displays in the events table
instantiated	The workflow is queued and will be started as soon as possible	"Pending"
running	The workflow is running, no problems so far	"Running"
stopped	The workflow was aborted by the user	"Processing canceled"
paused	The workflow was paused and can be continued	"Paused"
succeeded	The workflow has completed successfully	"Finished"
failed	The workflow failed due to an error	"Processing failure"
failing	The workflow is still running, but there were errors. It will fail.	"Running"

Using state mappings, it is possible to refine the labels displayed in the Admin UI events table for a particular workflow.

Here is an example which displays "Retracting" instead of "Running" for the retract workflow:

<?xml version="1.0" encoding="UTF-8"?>
<definition xmlns="http://workflow.opencastproject.org">
  <id>retract</id>
  ...
  <state-mappings>
    <state-mapping state="running">retracting</state-mapping>
    <state-mapping state="failing">retracting</state-mapping>
  </state-mappings>

When no state mappings are configured for a workflow, the generic default labels will be displayed.

When a workflow includes other workflows, the event table only shows the state of the including workflow.