SubMiner/backlog/tasks/task-43 - Add-community-subtitle-timing-database-for-shared-sync-corrections.md

id, title, status, assignee, created_date, labels, dependencies, priority

id	title	status	assignee	created_date	labels	dependencies	priority
TASK-43	Add community subtitle timing database for shared sync corrections	To Do		2026-02-14 02:13	feature community subtitles sync		low

Description

Allow users to share their subtitle timing corrections to a community database, so other users watching the same video file get pre-synced subtitles automatically.

Motivation

Subtitle synchronization (alass/ffsubsync) is one of the most friction-heavy steps in the mining workflow. Users spend time syncing subtitles that someone else has already synced for the exact same video. A shared database of timing corrections keyed by video file hash would eliminate redundant work.

Design

1. Video identification: Use a partial file hash (first + last N bytes, or a media fingerprint) to identify video files without uploading content
2. Timing data: Store the timing offset/warp parameters produced by alass/ffsubsync, not the full subtitle file
3. Upload flow: After a successful sync, offer to share the timing correction (opt-in)
4. Download flow: Before syncing, check the community database for existing corrections for the current video hash
5. Trust model: Simple upvote/downvote on corrections; show number of users who confirmed a correction works

Technical considerations

• Backend could be a simple REST API with a lightweight database (or even a GitHub-hosted JSON/SQLite file for v1)
• Privacy: only file hashes and timing parameters are shared, never video content or personal data
• Subtitle source (jimaku entry ID) can serve as an additional matching key
• Rate limiting and abuse prevention needed for public API
• Could integrate with existing jimaku modal flow

Phasing

• v1: Local export/import of timing corrections (share as files)
• v2: Optional cloud sync with community database

Acceptance Criteria

• #1 Video files are identified by content hash without uploading video data.
• #2 Timing corrections (offset/warp parameters) can be exported and shared.
• #3 Before syncing, the app checks for existing community corrections for the current video.
• #4 Upload of timing data is opt-in with clear privacy disclosure.
• #5 Downloaded corrections are applied automatically or with one-click confirmation.
• #6 Trust signal (confirmation count) is shown for community corrections.