CLOUDFLARE’S Streamline introduces a developer playground for building bespoke video pipelines on Cloudflare’s platform. It demonstrates how to render dynamic annotations on a livestream or create alternate video versions with burned-in subtitles by running a modular media workflow inside long‑lived containers. The system combines Cloudflare Stream with low‑level primitives to support real‑time video processing that persists beyond a single request and can publish output back as livestream or hosted video.
The architecture comprises two main parts: the Media Engine and the Application. The Media Engine runs in a Container and handles input/output and processing, with the Processor currently implemented via FFmpeg. The Controller, written in Go, exposes an HTTP API and translates requests into media engine operations. The Application is built with Workers and includes a user interface, an Orchestrator (a Durable Object) to manage session lifecycle, and a preview relay.
Streamline can operate locally or in Cloudflare, with the ability to start a session, ingest video chunks, and apply a pipeline of operations such as overlay, subtitle, filter, and encode, producing either RTMP or WebSocket outputs.
Security and openness are emphasised: access is restricted via Cloudflare Access, session isolation is enforced, and Streamline is released as open source with public playgrounds and example applications. The project provides client libraries and Durable Object exports for integration, plus hosted demos and links to the GitHub repositories for the media engine and demo applications.