Files
screen_cast/README.md
T
fegger 6e68300d05 build: add systemd autostart for the receiver
Ship systemd/screencast-receiver.service, a template the install
script substitutes (binary path, run user) and enables so the
receiver starts at boot after the network and avahi-daemon, with
restart-on-failure and a raised start limit for slow-booting boards.
SIGTERM gives the graceful shutdown that withdraws the mDNS
announcement — systemctl stop never triggers the stale-record trap
that kill -9 does. Headless consoles render via KMSDRM (the script
adds the run user to video/render/input); desktop autologin sessions
uncomment two documented Environment lines.

The install script gains SC_RECEIVER_SERVICE=0 to opt out.

Validated: systemd-analyze verify on the substituted unit (only the
expected missing /usr/local/bin path on this dev machine), and a live
lifecycle test as a user unit: the service-managed receiver announced
itself (--discover found it), systemctl stop produced a clean exit
(Result=success, no restart) and the mDNS announcement was withdrawn
immediately.
2026-09-07 12:30:26 +02:00

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2.2 KiB
Markdown

# screen_cast
A native Linux peer-to-peer screencast application.
- **Send** your desktop or a window to another Linux machine.
- **Receive** a stream and render it in a window.
- Discover receivers on the LAN via **mDNS/Avahi**; negotiate sessions with
**JSON signaling**; stream **H.264 over RTP/UDP**.
Built with **C++20**, **Meson**, **PipeWire**, **FFmpeg**, and **SDL3**.
## Quick start
Requirements:
- C++20 compiler with `<format>` (GCC 13+, Clang 18+)
- Meson >= 0.63, Ninja
- FFmpeg development packages (`libavcodec`, `libavutil`, `libswscale`)
- SDL3 development package (`sdl3`)
- nlohmann JSON (`nlohmann_json`) and Avahi client (`avahi-client`)
- For the sender only: PipeWire dev (`libpipewire-0.3`) and libportal
Build and run tests:
```sh
meson setup build
meson compile -C build
meson test -C build --print-errorlogs
```
Stream between two machines:
```sh
screencast --receive # machine A: announces itself, opens a window
screencast --send # machine B: discovers A, negotiates, streams
```
See `docs/RUNBOOK.md` for all modes, flags, and validation procedures.
## Receiver on a small ARM board (e.g. Raspberry Pi Zero 2 W)
The receiver does not need the sender's PipeWire/portal capture stack. On
the board, run:
```sh
sudo ./scripts/install-receiver.sh
screencast --receive
```
The script installs the dependencies, builds a receiver-only binary
(`-Dsender=false`), runs the test suite, and installs to `/usr/local/bin`
(override with `SC_RECEIVER_INSTALL_DIR`). It needs Raspberry Pi OS Trixie
or newer (GCC 13+ for C++20 `<format>`), builds SDL3 from source when the
distribution does not package it, and enables `avahi-daemon`. It also
installs and enables a systemd service so the receiver starts at boot —
`systemctl status screencast-receiver` to check on it.
Performance note: decoding is software H.264; on very small boards expect
smooth playback for modest resolutions and reduced frame rates at high
resolutions. Hardware decode is planned for Phase 7.
## Architecture
See `docs/ARCHITECTURE.md` for module boundaries and design rules.
## Roadmap
Development is split into phases in `docs/PHASES.md`.
Current phase: **Phase 7 — Resilience and polish**.
## License
MIT — see `LICENSE` (to be added).