Cobalt is a privacy-focused media downloader web application with a SvelteKit frontend and Node.js/Express API backend. Users paste a URL from supported platforms (YouTube, TikTok, Instagram, Twitter/X, Vimeo, Reddit, SoundCloud, Twitch, Bilibili, and 15+ others) and receive a downloadable media file. The architecture is a monorepo with three packages: @imput/cobalt-web (static frontend), @imput/cobalt-api (processing backend), and @imput/version-info (build-time version helper). The API acts as a fancy proxy - it fetches media streams from source platforms, optionally remuxes/transcodes via FFmpeg (server-side or client-side via libav.js WebAssembly), and streams results back without ever writing to disk. The frontend handles URL input, settings management (localStorage with migration), a processing queue with Web Workers for client-side FFmpeg, i18n (EN/RU), and PWA features. Key data flows: user submits URL → API validates/matches service → extracts stream URLs → returns tunnel/redirect/picker response → frontend either streams directly, proxies via API, or processes locally via Web Workers. External dependencies: FFmpeg (via ffmpeg-static), youtubei.js for YouTube, hls-parser, undici for HTTP, Redis (optional for rate limiting), Cloudflare Turnstile (optional bot protection).
Podsync is a Go-based service that converts video/audio content from YouTube, Vimeo, SoundCloud, and Twitch into podcast RSS feeds. It downloads media via yt-dlp, stores metadata in BadgerDB, and serves feeds via an HTTP server. The architecture is modular: platform-specific builders (pkg/builder/) query APIs to discover episodes, a downloader (pkg/ytdl/) handles media retrieval, and a feed generator (pkg/feed/) produces iTunes-compatible RSS and OPML. The system supports cron-based scheduling, episode filtering by regex/duration/age, cleanup policies, API key rotation, and hooks for custom workflows. It runs as a standalone binary or Docker container with local or S3 storage.
Plyr is a widely-used, client-side JavaScript library that provides a simple, accessible, and customizable media player for HTML5 video/audio, YouTube, and Vimeo. It is implemented as a modular class with plugins, utilities, and a comprehensive SCSS theming system. The library handles all aspects of media playback: custom controls, captions (VTT), fullscreen, picture-in-picture, AirPlay, speed and quality selection, preview thumbnails, and ads (Google IMA). It uses a build system based on Gulp and Rollup, produces ES and UMD bundles, and includes a polyfilled variant for older browsers. The codebase is well-organized with clear separation of concerns (controls, captions, fullscreen, listeners, storage, plugins) and extensive JSDoc documentation. However, it exhibits some technical drift, including legacy UA sniffing, a large controls module marked for refactoring, and deprecated build tooling. Despite this, the library remains actively maintained and is production-ready, with a robust demo site and a large user community.