Hydrogen is an advanced drum machine for GNU/Linux. It's main goal is to bring professional yet simple and intuitive pattern-based drum programming. Features:

General -- Very user-friendly, modular, fast and intuitive graphical interface based on QT 4. -- Sample-based stereo audio engine, with import of sound samples in .wav, .au and .aiff formats. -- Support of samples in compressed FLAC file.

Sequencer and mixer

-- Pattern-based sequencer, with unlimited number of patterns and ability to chain patterns into a song. -- Up to 192 ticks per pattern with individual level per event and variable pattern length. -- Unlimited instrument tracks with volume, mute, solo, pan capabilities. -- Multi layer support for instruments (up to 16 samples for each instrument). -- Sample Editor, with basic cut and loop functions. (NEW) -- Time-stretch and pitch functions via rubberband cli. Require the rubberband-cli package. (NEW) -- Play-lists with scripting function. (NEW) -- Advanced tab-tempo. (NEW) -- Director Window with a visual metronome and song position tags. (NEW) -- Time-line with variable tempo. (NEW) -- Single and stacked pattern mode. (NEW) -- Export/Import single patterns into song projects. (NEW) -- Midi learning via Shift+MouseClick on many gui-cotrollers combined with a midi settings editor. (NEW) -- Ability to import/export song files. -- Unique human velocity, human time, pitch and swing functions. -- Multiple patterns playing at once.

Other -- JACK, ALSA, PortAudio and OSS audio drivers. -- ALSA MIDI and PortMidi input with assignable midi-in channel (1..16, ALL). -- Import/export of drumkits. -- Export song to wav, aiff, flac or ogg file. -- Export song to midi file.