Select Tracks Workflow Operation
The select-tracks operation can be used in case not all source tracks should be processed. For example, given a recording with a presenter and a presentation track, the final recording to be published should only include the video stream of the presenter track and the audio stream of the presentation track.
The workflow operation will use workflow properties set by the Opencast video editor to determine which tracks should be
selected for further processing and add them to the media package based on
IMPORTANT: The input tracks need to be inspected using the workflow operation inspect before running this operation.
|source-flavor*||*/source||The flavor of the track(s) to use as a source input|
|target-flavor*||*/work||The flavor of the target track(s)|
|target-tags||download||The tags applied to all target tracks|
|audio-muxing||force||Move single-audio media packages to a specific track (see below)|
|force-target||presenter||Target track for the
* mandatory configuration key
The names of the workflow properties that control which streams are included in the output tracks are
"hide_" + source-flavor.type + "_audio" "hide_" + source-flavor.type + "_video"
For the source flavor
presenter/work, use the boolean workflow properties
hide_presenter_video to control which streams should be included in the output tracks.
Those properties are set by the Opencast video editor and can also be set using a custom workflow configuration panel.
audio-muxing parameter has three possible values:
none (same as omitting the option),
none is specified or the option is omitted, the audio stream is taken from the specified
source-flavor track and is
edited according to the selections in video editor’s “Tracks” panel. The resulting tracks are stored in the
target-tags are applied.
Note: If your editing results in a single video and single audio (track/stream) they will be muxed together even if
this option is set to
The parameter value
force only applies to media packages that have exactly one non-hidden audio stream. For media
packages without an audio stream or with more than one audio stream, the behavior is the same as if the parameter were
omitted. The same applies to media packages for which there is only one audio stream, and it already belongs to the
track with flavor type given by
presenter if that parameter is omitted).
If, however, there is only one non-hidden audio stream and it does not belong to the track given by
then the operation will “move” the audio stream to this target track. Specifically, it will mux the video stream of
force-target with the audio stream it found. Then, it removes the audio stream from the original track.
For example, consider a media package with two tracks, presenter and presentation. Both of these tracks have audio components, however the presenter audio stream is hidden. This WOH will mux presentations's audio stream with presenter's video, and remove the audio track from presentation's video.
The parameter value
duplicate only applies to media packages that have exactly one non-hidden audio stream and no
hidden video streams. For these media packages, the WOH will mux the audio stream it found to all video streams in
the media package. For media packages without an audio stream or with more than one audio stream, the behavior is
the same as if the parameter were omitted.
This workflow operation handler depends on the presence of the following encoding profiles:
|video-only.copy||Removes all audio streams from a media track|
|audio-only.copy||Removes all video streams from a media track|
|mux-av.copy||Mux a video stream and an audio stream into a media track|
Note that those encoding profiles are included in the default configuration of Opencast.
<operation id="select-tracks" description="Select tracks for further processing"> <configurations> <configuration key="source-flavor">*/source</configuration> <configuration key="target-flavor">*/work</configuration> <configuration key="audio-muxing">force</configuration> </configurations> </operation>