.FLP File Format

Introduction

An FLP file is a project saved by FL Studio, the music production software from Image-Line, first released as FruityLoops in 1997. It holds everything needed to rebuild the session: the channel rack and its instruments, patterns and their notes, the playlist, the mixer and its effects, plugin settings and the project details such as tempo, title and author.

The file holds no rendered audio. Samples are stored as paths to files on disk, and plugins as their saved state, so a project opens fully only where the same samples and plugins are installed.

The basic layout has not changed since the late 1990s, but what goes inside it has. Text encoding, the size of some records, the events in use and the number of tracks and mixer inserts all depend on the version of FL Studio that saved the file, so each version is described here as a format of its own, with its own reference. Image-Line described the format once, for FruityLoops 1.7 in 1999, and has not published it since. The details on these pages come from that document and from community reverse engineering, and some fields are still unknown.

Variations

Every version stores the version that saved the file as a text event (ID 199), such as 20.8.4.2576, near the start of the event stream. The eras below are told apart by that string. The boundaries are those used by open-source readers; Image-Line has not documented them.

Structure

In every version an FLP file is two chunks, each a four-letter ID and a little-endian length. The header chunk FLhd gives the file type, the channel count and the timing resolution. The data chunk FLdt holds the rest of the project as one long stream of events.

Each event is an ID byte followed by its value. The ID sets the size of the value: one, two or four bytes, or a length-prefixed block of text or data. There is no nesting. A New event starts a channel or a pattern, and in later versions an arrangement, and the events after it describe that item until the next one starts. Which events exist, and how their values are laid out, is set out in each version’s own reference.

The order shown inside the stream is a rough guide. Events of different kinds can appear in other orders, and a reader should handle each event by its ID wherever it appears.

Links