.SF3 File Format

Introduction

SF3 is a compressed form of the SoundFont 2 instrument bank. It was introduced by the developers of MuseScore, which ships its default sounds this way, to make large banks much smaller. It is not an official version from the makers of SoundFont 2: the structure is the same, but the samples are stored as Ogg Vorbis instead of raw PCM.

Structure

An SF3 file is a RIFF file with the form type sfbk, laid out exactly like an SF2 file with its INFO, sdta and pdta lists. The differences are that the version in the ifil chunk has major number 3, the smpl chunk holds each sample as a separate Ogg Vorbis stream, and the sample headers flag those samples as compressed and give their start and end as byte offsets into smpl rather than sample counts. Instruments and presets are unchanged.

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