Often an audio or video resource will have content that is part of the object but not significant, such as a microphone check, or audience noise before the start of a performance, or a test card. The
start property allows the publisher to specify a point where a client application should begin playback.
This recipe extends Simplest Manifest - Video by adding the information required by a client to start playback at a particular point. This is done by adding the
start property to the Manifest with the start time in seconds.
The target of
start must be a JSON object with
type properties and can be either a Canvas, or a Specific Resource with a Selector and a
source property where the value is a Canvas.
In this use case, the target
type property is a Specific Resource (
"type": "SpecificResource"), and the Selector
type property is a Point Selector (
"type": "PointSelector") that identifies a starting time point (
"t": 120.5) within the
For more on the
start property, see: Start Property.
About selector classes:
Selectors in Annotation targets are used to describe how to retrieve a given part of a resource. There are three Selector classes defined in the IIIF specification, but only the
PointSelector class is appropriate for this use case. The
PointSelector class defines a specific point either spatially (
y) and/or temporally (
This example shows a Manifest with a single Canvas with a duration of 1801.055 seconds. It has a single video file (30-minute-clock.mp4) which is associated with it. The
start property specifies a start point of 120.5 seconds into the playback. The video was created by DrLex1 and was released using a Creative Commons Attribution license.
Note: As of the writing of this recipe, playback of video content is supported by some viewers (Universal Viewer), but the
start property for time-based objects is not yet supported in viewers.