# Trick-play track via the Image Media Playlist specification
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In an HLS output group, you can support a trick-play track by providing an asset that follows the Image Media Playlist specification, version 0.4. The Elemental Live implementation follows the time-based method of the specification. The specification is located here:

[https://github.com/image-media-playlist/spec/blob/master/image_media_playlist_v0_4.pdf](https://github.com/image-media-playlist/spec/blob/master/image_media_playlist_v0_4.pdf)

Roku is one example of a platform that implements this specification.

## How the method works
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When you create the output group, you create standard outputs in the usual way for the video, audio, and captions encodes. 

You also create one or more outputs that each contains one encode (stream). This encode is the asset that the downstream player can use to implement the trick-play track. The encode consists of a series of JPEG files, with one file for every video segment. This means that the capture follows the segmentation of the video encode, which means it provides the best experience on the video player. 

Elemental Live creates a main manifest and child manifests in the usual way. The main manifest includes an `EXT-X-IMAGE-STREAM-INF` tag for the frame capture encode. The child manifest for the frame capture encode contains `EXT-X-IMAGES-ONLY` tags. The contents and format of these tags comply with the Image Media Playlist specification.

## Setting up
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You set up the trick-play track in the output group by creating an additional output that contains a video encode that consists of frame captures.

**Note**  
The information in this section assumes that you are familiar with the general steps for creating an event.

**To set up the frame capture encode in an HLS output group**

To create a frame capture encode in an HLS output group, you create an output, and set up the video stream to use the **Frame Capture to JPEG** video codec.

1. In the **HLS Output Group**, in **HLS Outputs**, choose **Add Output** to add another output.

1. For that output, go to the Video section in the corresponding Stream section. 

1. Choose **Video** and set up the video fields, including:
   + **Video Codec** – Choose **Frame Capture to JPEG**. 
   + **Resolution** – Contact your downstream system to obtain the correct width and height. If you guess at the values, the experience on the downstream player might not be optimal.
   + **Trick Play** – Select this field. Many of the remaining fields disappear.

1. Choose **Audio 1** and choose **X** to remove the audio stream. The output must have only one encode (a video encode).

The output is part of the ABR stack and has the same destination as the other encodes in the HLS output group.