SPICE Remote Computing Protocol

SPICE (Simple Protocol for Independent Computing Environments) is a free and open-source remote computing protocol designed for accessing virtualized desktop environments. Originally developed by Qumranet (founded by Benny Schnaider, Rami Tamir, and Yoram Yasur in Israel) in 2003, SPICE was acquired by Red Hat in 2008 when Red Hat purchased Qumranet for $107 million. Red Hat open-sourced SPICE in December 2009 under the GNU GPL. The project is now maintained by the SPICE Project community with Red Hat as the primary contributor. Key features: high performance: SPICE is designed specifically for virtual machine (VM) remote display, offering better performance than VNC or RDP for VM console access. It uses adaptive graphics compression, local cursor rendering (the client renders the mouse cursor locally to avoid round-trip latency), and video detection (automatically switches to streaming mode for video content). Multi-monitor: support for multiple monitors on the guest VM, with each monitor displayed in its own window on the client. Hardware acceleration: QXL (the SPICE video driver) provides 2D hardware acceleration for the guest. The QXL device is implemented in QEMU/KVM. Audio: bidirectional audio support (playback and recording) between guest and client using CELT or Opus codecs. USB redirection: redirect USB devices from the client machine to the guest VM over the network, enabling use of local USB devices (printers, scanners, flash drives) in the virtual machine. Smartcard redirection: use local smartcard readers for guest authentication. File transfer: drag-and-drop file sharing between client and guest. Clipboard sharing: copy and paste text and images between client and guest. Architecture: consists of spice-server (library used by QEMU), spice-client (remote-viewer), spice-protocol (shared protocol definitions), and vdagent (guest agent for clipboard, mouse, and resolution sync). Integrates with libvirt and GNOME Boxes. C/C++. LGPL-2.1+.