[2] It is open-source, and runs on most major modern platforms including Windows, Mac OS X, and Linux.
Support is included for NTSC, PAL and SECAM in 60 Hz/50 Hz varieties, including autodetection of those formats (based on the number of scanlines generated in each frame).
Stelladaptor and 2600-daptor support allows real joysticks, paddles, and driving controllers to be used, and support is also included to access a real AtariVox device plugged into a serial port (and actually generate sound from the AtariVox device).
Stella does not yet support the cassette-based titles designed to work with the Coleco KidVid cassette player but does have support for titles designed to work with the Starpath Supercharger and Spectravideo Compumate.
Other major features include Blargg TV effects, a cheatcode system, support for user-defined palette files, state loading/saving (including a TimeMachine-like unwind/rewind capability), hardware-accelerated rendering and effects, event remapping, and an extensive built-in, cross-platform user interface (including a ROM launcher frontend).