Back in 2001, Donald Norman highlighted the failures of DVD menu design. Much research on DVD menu design has been done since then. Unfortunately, DVD subtitle usability doesn’t seem to have received the same attention.
Selecting DVD subtitles is a two-step process:
However, the remote controls of many DVD-players overload these two steps onto a single button. Pushing the subtitle button once turns the subtitles on by selecting the first language in the list. Each subsequent button push selects the next language in the list. When the DVD player reaches the end of the list, the next push of the subtitle button turns the subtitles off.
In the simplest case, a DVD will have subtitles in one language. Toggling the subtitles on and off requires only two button pushes: one to turn the subtitles on by selecting the one language on the list; another to turn the subtitles off. The usability problem of this design is that it doesn’t scale well. For example, one of my DVDs has subtitles in ten languages:
The list of languages on other DVDs is even longer. And when you include the subtitles for an extra commentary track in each language, the list can double.
Toggling the subtitles on and off for a ten-language DVD requires many button pushes. In the worst case, when the first language on the list is selected, turning the subtitles off requires ten button pushes: nine to step through the subtitles for the remaining languages in the list, and one to turn the subtitles off. Unfortunately, since I only ever select English subtitles, the worst case is also the usual case.
Quickly toggling subtitles on and off is useful when one wants to rewind the movie to read dialogue that is unclear on the audio track, perhaps because of background music or an unfamiliar accent or dialect.
One-button and two-button solutions to this subtitling usability problem spring to mind. In the one-button solution, pressing the button would step through each subtitle language; pressing and holding the button would display or hide the text on the screen. In the two-button solution, pressing one button would step through each subtitle language; the other button would display or hide the text on the screen. Both designs should be tested with users.