Evaluating the positioning of BBC Subtitles

User Experience & Usability

The BBC have been providing subtitles for all their video content since the 1980’s. They provide a transcript of a video, helping viewers with hearing impairments to follow programmes. Over 10% of people use subtitles on a daily basis to help with hearing or language barriers.

It is not just users with disabilities that engage with subtitles, however. Use cases might include;

  • When on sites such as Facebook, Instagram and Twitter, with auto-start videos that have sound switched off as default, users commonly use subtitles to consume content
  • When users want to watch video content on mobile without disturbing others in the same room
  • Being on public transport where it might be more difficult to hear due to background noise.

The challenge

Subtitles generally appear by default at the bottom of the screen, however, programme makers also have the option to place these subtitles in different positions on the screen. This is beneficial if, for example, there is important information (such as a phone number) at the bottom of the screen that would otherwise be obscured by the subtitles. Subtitles could therefore temporarily move to the top of the screen and then move back to the bottom of the screen when the important information has disappeared. These moving subtitles are called positional subtitles.

New video controls were planned for iPlayer on mobile, with the user interface elements (e.g. play/pause and seek controls) appearing in the middle of the screen. This was in keeping with previous research on device ergonomics and usage. However, the first build version of the new UI could sometimes obscure the subtitles, depending on where the subtitles were placed at the time the UI components are invoked, whereas previous player versions enabled the subtitles to respond to obstructive onscreen controls (such as the scrub-bar) and reposition them above the UI.

Mobile phone playing BBC iPlayer with subtitles

As part of their ongoing work to improve the user experience of their online video players, the BBC wanted to conduct research with a range of users to understand the experience of the new planned video controls for mobile iPlayer when watching video content with subtitles.

What we did

To understand a range of experiences when interacting with the new video controls whilst viewing subtitles, we tested with a cross-section of users who have subtitles turned on when viewing video content on their mobile phone. Participants included those with; no disabilities, hearing impairments, cognitive impairments and learning difficulties. To understand if there was a relationship between the position of the subtitles and the new UI control elements, we explored three different subtitles ‘states’; at the bottom of the screen below the scrub bar; at the top of the screen; and at the bottom of screen, above the scrub bar.

Three different subtitle states viewed by participants.

During the sessions, it was important to understand, as far as possible, the natural experience, without interruption to the user. To do this, we asked users to wear headphones if they normally would, made use of simulated background noise, and provided the tasks before the session had started. Whilst interacting with the iPlayer, we used cue cards to prompt on tasks, to avoid (as much as possible) engaging with participants as they carried out their task.

By capturing these more immediate, natural reactions, we were able to gather insights into how the users’ experience was impacted – negatively, or otherwise. After the natural interactions, we stepped back through the scenarios, probing retrospectively on specific areas of interest after each task. This allowed us to delve deeper into behaviours and attitudes, though it was important to consider the immediate vs. retrospective feedback given, in the wider context of the results.

We also explored alternative interactions between the subtitles and UI controls using mock-ups, to supplement the insights and provide future considerations for the BBC team.


By testing with a range of users, the BBC were able to understand how experiences may be impacted by those with different viewing needs. There is a continual balancing act between not obscuring the programme content or any on-screen text, and positioning of subtitles on the screen in a way that causes the least disruption for users. The insights from the research provided support in the direction of the new UI, helping to inform the team’s next steps.

During the sessions a number of insights also emerged, which did not directly relate to the research objectives. These presented some interesting considerations for the team in the future, as they continue to monitor, review and inform future iterations of the design.

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