yutto is a production-grade CLI application for downloading videos, subtitles, danmaku (bullet comments), and metadata from Bilibili. In production it resolves user-supplied URLs (UGC videos, bangumi anime, paid cheese courses, favourites, collections, watch-later lists) against Bilibili's private JSON APIs, normalizes responses into typed Pydantic download requests, and runs a planner/executor pipeline: immutable DownloadPlan construction (output paths, codec/quality selection), concurrent range-based downloading, FFmpeg muxing, and writing of NFO/SRT/ASS artifacts. It also ships an experimental WebSocket JSON-RPC server mode (`yutto serve`) for remote task submission, querying, cancellation, and live event streaming with token authentication.
Kazumi is a cross-platform Flutter application for browsing, collecting, and streaming anime (番剧). At its core, it provides a curated media experience: users can discover anime via popularity rankings, weekly schedules, text and image (trace.moe) search; manage a local watchlist synced with Bangumi (bgm.tv) and WebDAV; and play videos using a hardware-accelerated media_kit (libmpv) player with danmaku overlay, Anime4K super-resolution shaders, Picture-in-Picture, and external player support. It also downloads episodes (HLS segments) for offline playback and supports synchronized group viewing via the Syncplay protocol. The application is built as a Flutter monolith with modular routing (flutter_modular), reactive state management (MobX), local storage (Hive), and a custom plugin system that defines scraping rules (XPath/API) to extract video sources from third-party websites. External dependencies include Bangumi, DanDanPlay, trace.moe, WebDAV servers, and a GitHub-hosted plugin catalog. The codebase demonstrates mature engineering practices including well-isolated async utilities, event-sourced history sync with conflict resolution, and platform-specific WebView integrations for video source extraction and captcha handling.