Architecture & Performance

OSMV v5.1.0 is written in native C++20 using a dual-process architecture engineered for minimal RAM and near-zero idle CPU usage while streaming.

The Dual-Process Model

Keeping a graphical context and GPU driver buffers open in the background consumes unnecessary memory during a stream. OSMV isolates background polling from the UI:

1. The Background Daemon:
   • Windows (OSMV.exe): Single portable executable (~1.94 MB, no external DLLs). DirectX 11, DXGI, and DWM DLLs are marked /DELAYLOAD so the daemon never maps GPU libraries into memory, consuming only ~4.5 to 6 MB of private RAM.
   • Linux (osmv): Built as a standalone daemon binary that links only libdbus-1, libcurl, and pthreads—zero X11, Wayland, OpenGL, or GTK dependencies.
   • Handles media polling (WinRT SMTC / D-Bus MPRIS), Discord IPC, Time/Date/Timers, native System Info sampling, Textline Changer, and a dedicated network worker thread for Dynamic Files and Twitch Helix so HTTP calls never stall local 1-second timers.
2. The Configuration GUI (--gui / osmv-gui):
   • Uses Dear ImGui (Win32 + DirectX 11 on Windows; GLFW + OpenGL 3 on Linux) with event-driven frame pacing (0.25s when idle, 0.016s during animations or user input).
   • Uses ~51 to 58 MB of private RAM on Windows while open.
   • Closing the window [X] or clicking Mode Headless / Minimize to Tray terminates the GUI process and releases 100% of its graphics memory back to the OS immediately.

Execution Flow

• Startup: Running OSMV.exe (or ./osmv) acquires a single-instance lock (Local\osmv-daemon-instance-v3 on Windows, flock in $XDG_RUNTIME_DIR on Linux).
  • If no daemon is running: starts the background daemon, initializes the system tray icon (Shell_NotifyIconW on Windows; D-Bus StatusNotifierItem + com.canonical.dbusmenu on Linux), and launches the GUI unless --silent is passed or Open GUI on launch is disabled.
  • If a daemon is already running: sends a show_gui IPC message to wake/open the GUI and exits.
• Headless Mode: Closing the GUI window keeps the daemon running unobtrusively in the system tray.
• Quit: Clicking Quit OSMV in the GUI or tray menu signals the daemon to shut down cleanly and clears shared/current_song.json and shared/current_song.js (null).

Local IPC & Disk Optimization

The daemon and GUI communicate over a length-prefixed JSON local IPC channel:

• Windows: Named Pipe \\.\pipe\osmv-ipc-v3
• Linux: Unix Domain Socket $XDG_RUNTIME_DIR/osmv-ipc-v3.sock (fallback /tmp/osmv-ipc-v3-<uid>.sock)

Key performance optimizations:

• Instant IPC Control: The GUI polls get_state every 500 ms only while open and sends reload_settings, chrono_down, chrono_up, textline_next, twitch_search_games, twitch_update_channel, and quit commands without duplicating WinRT/MPRIS polling in the GUI process.
• Change-Cached Atomic Writes: Text files are tracked in memory (CachedTextWriter) and written atomically via .tmp + rename only when their formatted output actually changes.
• Track-Change Artwork Caching: Album artwork streams from WinRT/MPRIS are read and Base64-encoded only when the track changes, eliminating per-second image allocations.