At VideoA11y, we’re committed to ensuring that video content is accessible to all, including users with motor disabilities. Our recent case study focused on designing accessible video player scrubbing controls for Connected TV apps, optimizing them for diverse user needs. This study improves the usability of video scrubbing controls for remotes, while accounting for the needs of text-to-speech users for accurate script updates.

Key Concepts: Accessible Video Scrubbing

To better understand the impact of our proposed solutions, let’s define some key terms:

  • Scrubbing: Fast-forwarding or rewinding through a video via a progress bar.
  • Interval: The unit of progress movement on the video timeline.
  • Skip Rate: The time between each interval when scrubbing.
  • Scrubbing Speed: The amount of time skipped per interval.

Goals of Accessible Video Scrubbing for Connected TV Players

Our main objective was to enhance the user experience for all, especially those with motor disabilities such as Cerebral Palsy, MS, and Arthritis. We aimed to:

  • Eliminate press-and-hold interactions, which can be challenging for users with limited motor control.
  • Provide better support for basic remote controls (like d-pads) with limited buttons.
  • Calculate relative scrubbing speeds for videos of varying lengths (from 1 minute to 4 hours).
  • Improve the experience for Text-to-Speech (TTS) users by providing timely updates on the playback timeline.

Accessible Remote Control Functionality

For remotes with limited buttons, such as d-pads, our solution focuses on simplifying controls:

  • We removed the need for “press and hold” interactions, instead relying on d-pad navigation to adjust scrubbing speed.
  • We ensured that users can toggle between 2x, 4x, and 8x speeds with a single button press, maintaining compatibility with advanced remotes while accommodating simpler ones.

The Proposed Accessible Video Scrubbing Solution

Our solution redefines the scrubbing experience using the d-pad on Connected TV remotes, offering smoother control and better accessibility for users with motor impairments. Here’s how:

  • The scrubbing speed is set at 1 interval per second, with TTS updates delivered every 4 intervals. This gives users enough time between updates to hear concise timestamp updates, regardless of their TTS speech rate.
  • We implemented scrubbing speeds labeled 1x (standard playback), 2x, 4x, and 8x, which are typical in video player designs and familiar to most users. These speeds do not represent a static doubling of speed and are calculated relative to the video length.

Technical Calculations

If you are a video player developer, you’ll certainly appreciate this math. Otherwise, this information gets a bit technical in order to explain the process of accessible scrubbing. If you don’t understand it, please reach out to us. We are more than happy to explain it in a conversation instead of text.

v = the total video length

y = the 2x (relative) scrubbing speed

y = v/240 + 1.75

If you would like to learn more about how my teammate, Jaidynn Fohr, ended up with this function, please see the Supplemental Math section in our doc.

Accessible Scrubbing Examples

Using these calculations, we can know exactly how the accessible scrubbing solution works in a 30-minute video:

  • At 2x speed, there are 141 intervals of 4.25 seconds producing 35 TTS updates over a total scrub time of 2 minutes and 21 seconds.
  • At 4x speed, there are 70 intervals of 8.5 seconds producing 17 TTS updates over a total scrub time of 1 minute and 10 seconds.
  • At 8x speed, there are 35 intervals of 17 seconds production 8 TTS updates over a total scrub time of 35 seconds.

If you compare that with a 2-hour video, you’ll notice that the intervals change giving the user finer control over the scrub:

  • At 2x speed, there are 226 intervals of 31.74 seconds producing 56 TTS updates over a total scrub time of 3 minutes and 46 seconds.
  • At 4x speed, there are 113 intervals of 63.5 seconds producing 28 TTS updates over a total scrub time of 1 minute and 53 seconds.
  • At 8x speed, there are 35 intervals of 17 seconds production 8 TTS updates over a total scrub time of 35 seconds.

For a 4-hour video:

  • At 2x speed, there are 233 intervals of 61.75 seconds producing 58 TTS updates over a total scrub time of 3 minutes and 53 seconds.
  • At 4x speed, there are 116 intervals of 123.5 seconds producing 29 TTS updates over a total scrub time of 1 minute and 53 seconds.
  • At 8x speed, there are 58 intervals of 247 seconds producing 14 TTS updates over a total scrub time of 48 seconds.

Enhancing the Scrubbing Experience for Text-to-Speech Users

A critical component of our solution is optimizing the scrubbing experience for TTS users. By implementing TTS updates every 4 seconds, users receive clear, timely information on their position within the video. This feedback loop ensures they remain aware of their location in the video without being overwhelmed by constant updates.

Why These Changes Matter

These improvements aim to make video content more accessible for users with motor impairments while also enhancing usability for those relying on TTS. With our accessible video scrubbing controls, traversing through video is smoother, more intuitive, and accessible.

By providing flexible, easy-to-use player controls and ensuring compatibility across various remote types, we’re paving the way for a more inclusive video experience on Connected TV platforms.

Join VideoA11y

At VideoA11y, we are passionate about driving accessibility in the video entertainment industry, ensuring that everyone can enjoy the content they love. If you’re as committed to inclusivity as we are, we invite you to join us in creating accessible solutions for video platforms.