ClearLine

Inspiration

When a viewer misses a sentence, repeated rewind can interrupt the story and still miss the right moment. ClearLine explores a more direct interaction: select the caption line you missed and replay it.

What it does

ClearLine is a caption-first TV video player built for remote navigation. Up or Menu opens the last 30 seconds of dialogue. Browse the timestamped lines and press Select to replay a cue with 300 ms of pre-roll. Down opens caption controls for text size, background and position; preferences apply live and are saved. Back closes the panel or settings and returns focus to playback.

How we built it

We built the Android app in Kotlin using Android Views, AndroidX and Media3. The player loads approved local video with bundled WebVTT captions. A state reducer handles remote keys, dialogue selection, playback recovery and focus. The release build disables the separate research configuration and study logging. The source includes setup instructions, a signed APK release and a separate comparison-study toolkit. Development work is recorded in the repository during the hackathon window.

Challenges

TV navigation required deliberate handling of repeated keys, focus restoration, buffering and Back behavior. Remote video playback failed in the Amazon virtual lab during earlier testing, so the reproducible demo path uses the approved video locally.

Accomplishments and what we learned

The prototype implements caption history, cue-based replay and saved caption preferences. The signed release was installed and demonstrated on an Android TV emulator: playback, recent-dialogue selection, replay confirmation, live caption settings and return to playback were visually verified for this submission. Repository records also document unit tests and prior TV-emulator smoke checks. We learned to separate software verification from evidence of customer benefit: controlled participant trials remain pending, and we do not claim measured accessibility or speed improvements.

Scope and next steps

ClearLine operates inside its own player; it does not read captions from other streaming apps. There is no AI, AWS integration or DRM support. Next steps are consented user trials, broader device validation and human checks of audio, distance readability and accessibility.

Source and installation

Use the v1.0.0-release tag or task7-release branch, rather than the old main branch. The release README explains installation and how to supply the demo media.

Credits

Tears of Steel (2012), (CC) Blender Foundation | mango.blender.org, licensed CC BY 3.0 (https://creativecommons.org/licenses/by/3.0/). English captions were converted to WebVTT. The supplied source film remains unaltered with full credits.

Primary track: Fire TV. Mini challenges: none.

Built With

• kotlin