Future Media Standards & Guidelines

How to Use the EMP to Deliver Subtitles

1. Purpose

This document explains how to use the EMP to deliver subtitles for scheduled, off-schedule, and archived programmes, marketing trails, user-generated content and games.

For further information about delivering A/V content for BBC online, refer to the A/V Streaming Standards and the A/V Addendum.

For further information about delivering subtitles files for online A/V content refer to the Subtitling Guidelines.

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2. Subtitles for the EMP

If you are using the EMP to deliver subtitles you must provide the files in timed-text format. If your subtitles are already in EBU-STL format, you will need to email the subtitles files to Andrew Strachan in the Usability and Accessibility Team in Central UX&D so they can be converted to timed-text format using our in-house subtitles conversion facility (SCF).

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3. Recommended directory structure and file naming conventions

The recommended directory structure for hosting the holding image, Flash video, subtitles and playlist for the EMP is as follows:


For further information about implementing the EMP, refer to the EMP website Restricted access – post-NDA only.

When naming the files themselves, ensure that the file names are the same (bar the extension) for each asset whenever possible. The assets include the subtitles file, image, Flash video and playlist.

The naming structure of timed-text subtitles files for A/V content is as follows:


For example:



  • ProgName can be abbreviated to represent the programme title (for example, sja is abbreviated for the Sarah Jane Adventures programme);
  • sXX represents the series number; and
  • epYY represents the episode number.

Make sure you confirm the file name for each video clip in advance before subtitles are provided.

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4. Adding subtitles to the EMP playlist

For complete instructions and guidance on creating a playlist for the EMP, refer to the EMP website Restricted access – post-NDA only.

You will need to add a captions element to the playlist, as shown in the following example:

<media kind="captions" type="application/ttaf+xml">
	<connection kind="http" href="http://www.bbc.co.uk/missingmodel/emp/subtitles/debbie.xml"/>

You will also need to use the EMP playlist generator to help create the playlist using the URL for the holding image, subtitles, and details of the Flash video. This will help ensure that the subtitles work for the EMP before publishing it on your site.

Including the caption element within the playlist will display the 'S' subtitles toggle button on the control panel of the EMP. The 'S' button will appear after the user chooses 'Click to play'. From a user experience perspective, you should highlight the availability of subtitles next to the EMP.

If the URL for the subtitles within the caption element of the playlist is missing or incorrect, the EMP will display an 'S' subtitles toggle button and the message 'Subtitles not available'.

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