<img src="https://img.shields.io/badge/%20-ENTERPRISE-%23B10031" style="float:left"/><br /> <img src="https://img.shields.io/badge/Android-V4-009727?logo=android" style="float:left"/>
JWP supports the loading of preview thumbnails for individual shots or scenes in a video. These thumbnails are displayed in a tooltip when a viewer hovers the control bar.
<br /> <hr />
## Preview thumbnail overview
In the Android SDK, you define your preview thumbnails in a single .vtt file. The .vtt file is part of a thumbnail `
Caption` that is assigned to a `
For an optimal user experience, the thumbnails should adhere to the following:
URLs must point to individual thumbnail files (**filename.jpg**) or to the [spacial media fragment](🔗) (**filename.jpg#xywh=0,0,120,90**) in a thumbnail sprite
URLs must be relative to the .vtt file
Thumbnail width of 100-150 px
When a media asset is uploaded to your JWP account, a thumbnail track file is created as part of the transcoding process. So, instead of creating a new **.vtt** file for a video asset, you can copy the URL of the thumbnail track file from your JWP dashboard.
To locate the thumbnail track of a specific video asset, follow these steps:
Click the name of the video in your JWP dashboard [Media Library](🔗).
Under **Media Summary**, click the **View Assets**.
On the **Tracks** tab in the **Thumbnail Preview** row, click <strong>∨</strong> to reveal the **DIRECT URL**.
Copy the **DIRECT URL**.
<br /> <hr />
## Adding preview thumbnails to an app
In your main activity, create a `
List<Caption>` object and name it, for example, `
Create a `
Caption` object and name it, for example, `
In the `
Caption` object, define the preview thumbnail .vtt file URL (`
file`). You can use the .vtt file mentioned in the TIP box above that JWP creates during the transcoding process.
Define the `
Caption` object as a thumbnail track (`
previewThumbnail` to `
thumbnailTrack` to a `
(Optional) Add `
thumbnailPreview` to `
PlayerConfig` to configure the appearance of the thumbnail preview.<br /><br />The default setting is `
THUMBNAIL_PREVIEW_TEXT_AND_IMAGE`. You can also configure the thumbnail preview as text-only (`
THUMBNAIL_PREVIEW_TEXT`) or image-only (`
### Add preview thumbnails to existing captions
If you have an existing [captions](🔗) track, you should add preview thumbnails to that existing `
tracks` list. Creating a new `
tracks` list for preview thumbnails will cause only the most recently added `
track` to load.
The following code example illustrates how a preview thumbnail can be added to an existing caption track setup and associated with a playlist through `