uStreamer is a lightweight, high-performance MJPEG-HTTP video streaming server designed primarily for PiKVM (IP-KVM over HDMI). It captures video from V4L2 devices (USB cameras, HDMI capture cards) and streams it as MJPEG over HTTP with sub-second latency, while also supporting H.264 streaming via WebRTC through a Janus plugin. The system is a single, multithreaded C daemon with pluggable JPEG encoders (CPU via libjpeg-turbo, hardware passthrough, and V4L2 M2M acceleration) and includes a worker pool for parallel encoding. It integrates tightly with Linux multimedia subsystems (V4L2, ALSA, DRM) and provides additional features like audio capture/playback with Opus encoding, GPIO control, systemd socket activation, and shared memory IPC for zero-copy frame access by other processes (e.g., Janus, Python bindings, dump tool). The codebase is production-grade, extensively tested in the PiKVM ecosystem, and packaged for multiple Linux distributions and container environments. The architecture separates concerns into clean modules: capture (V4L2 buffer management with DMA export), encoding (abstraction over CPU/HW/M2M), HTTP server (libevent-based, serving MJPEG streams, snapshots, and static assets), and a generic worker thread pool for parallel JPEG compression. Shared memory sinks (memsink) enable efficient frame transfer to external consumers like the Janus WebRTC plugin or the standalone dump utility. The project also includes a full-featured Janus plugin for H.264/Opus streaming with NTP timestamping and PLI handling, a Python C extension for shared memory client access, and a separate V4 passthrough tool for the PiKVM V4 Plus hardware. Build configuration uses Makefiles with numerous feature flags (WITH_GPIO, WITH_JANUS, WITH_SYSTEMD, etc.), permitting a modular build. Overall, uStreamer exemplifies careful engineering of real-time video pipelines on embedded Linux, with a focus on minimal latency, hardware offload, and robust IPC.