video-setup

A graph-based multi-peer video routing system written in C11. Nodes are media processes connected by typed transport edges; the graph carries video streams between sources, relays, and sinks with priority as a first-class property — so a low-latency monitoring feed and a high-quality archival feed can coexist on the same source.

Designed to run on resource-constrained hardware (Raspberry Pi capturing raw MJPEG, forwarding over TCP) alongside more capable machines that handle processing, relay, display, and archival.

Documentation

• architecture.md — system design: graph model, transport protocol, relay design, codec layer, discovery, multi-site plan, device resilience, X11 integration
• docs/protocol.md — wire protocol reference: frame format, all message types, payload schemas, stream lifecycle, discovery
• planning.md — module build order and current status
• conventions.md — C code and project conventions

CLI Tools

• docs/cli/media_ctrl_cli.md — media device and topology tool
• docs/cli/v4l2_ctrl_cli.md — V4L2 camera control tool
• test_image_cli — generate test patterns and write PPM output for visual inspection
• xorg_cli — display a test pattern in the viewer window; exercises scale/anchor modes and text overlays
• v4l2_view_cli — live camera viewer; auto-selects highest-FPS format, displays FPS overlay
• stream_send_cli — capture MJPEG from V4L2, connect to a receiver over TCP, stream VIDEO_FRAME messages with per-stream stats
• stream_recv_cli — listen for incoming TCP stream, display received MJPEG frames with fps/Mbps overlay

Structure

src/modules/     C modules, one directory each
include/         public headers
dev/cli/         CLI driver programs for each module
dev/web/         development web UI (Node.js/Express) — connects to live nodes for V4L2 inspection and control
tools/           build-time code generators (e.g. gen_font_atlas — bitmap font atlas for xorg text overlays)
docs/            documentation

Status

Core modules and the video node binary are working. The node can be queried over the wire protocol for device enumeration and V4L2 camera control. The development web UI connects to live nodes for inspection and control. The xorg viewer sink is implemented (GLFW+OpenGL, all scale/anchor modes, bitmap font atlas text overlays). A V4L2 capture viewer (v4l2_view_cli) demonstrates live camera display without going through the node system. Frame ingest-to-wire and relay have not started.

Module	Status	Notes
common	done	Error types, base definitions
config	done	INI file loader, schema-driven defaults, typed getters
media_ctrl	done	Media Controller topology, pad format config
v4l2_ctrl	done	V4L2 control enumeration, get/set
serial	done	Little-endian binary serialization primitives
transport	done	Framed TCP stream, single-write send
discovery	done	UDP multicast announcements, peer table, found/lost callbacks
protocol	done	Typed write/read functions for all message types
node	done	Video node binary — config, discovery, transport server, V4L2/media request handlers
dev/web	done	Development web UI — connects to live nodes, V4L2 inspection and control
test_image	done	Test pattern generator — colour bars, luminance ramp, grid; YUV420/BGRA output
xorg	done	GLFW+OpenGL viewer sink — YUV420/BGRA/MJPEG input, all scale/anchor modes, bitmap font atlas text overlays; screen grab and XRandR queries not yet implemented
frame_alloc	not started	Per-frame allocation with byte budget and ref counting
relay	not started	Input dispatch to output queues (low-latency and completeness modes)
ingest	not started	V4L2 capture loop — dequeue buffers, emit frames
archive	not started	Write frames to disk, control messages to binary log
codec	not started	Per-frame encode/decode (MJPEG, QOI, ZSTD-raw, VA-API H.264)
web node	not started	Node.js peer — binary protocol socket side + HTTP/WebSocket to browser