Free online OGG to SF2 converter

What the OGG format is

OGG is a multimedia container commonly used with the lossy Vorbis audio codec. It is created by applications such as Audacity, VLC-based tools, game audio pipelines, and music encoders, and commonly appears in downloaded music, voice recordings, and software assets. An OGG/Vorbis file stores compressed audio; it does not normally contain the playable instrument zones and MIDI mappings required by a SoundFont.

What the SF2 format is

SF2, or SoundFont 2, is a sampled-instrument format used by software synthesizers, MIDI players, notation programs, and hardware sound modules. An SF2 file can contain one or more PCM samples, loop points, root notes, key and velocity ranges, amplitude envelopes, tuning, effects, instruments, and presets. Its main advantage over a standalone audio file is that a sampler can play the embedded sample at different pitches and velocities from a MIDI keyboard or sequence.

How to convert OGG to SF2

The reliable workflow is to decode the OGG to WAV, then build a SoundFont around that WAV. FFmpeg performs the audio conversion, and Polyphone creates the SF2 structure.

1. Decode the source with FFmpeg:
   ffmpeg -i input.ogg -acodec pcm_s16le sample.wav
   This produces a 16-bit PCM WAV. Use -ar 44100 to force a 44.1 kHz sample rate or -ac 1 for mono when the target sampler requires those settings.
2. Open Polyphone and create a new SoundFont with File → New.
3. Import sample.wav into the SoundFont's sample list. Trim silence or unwanted material first in an audio editor such as Audacity if the OGG contains a complete song rather than a single instrument note.
4. Create an instrument and assign the imported sample to a zone. Set the sample's root key to the note at which it was recorded, then define the key range. For a one-shot sound, disable looping; for a sustained note, set loop start and end points and check the loop by playing across the keyboard.
5. Create a preset, assign the instrument to it, set the preset name and MIDI bank/program values if required, and save with File → Save as using a filename such as instrument.sf2.

For a quick automated attempt, you can convert the file on the 101convert.com website for free without installing software. A service can decode the audio and create a basic SoundFont, but it may not choose a useful root note, loop, key range, envelope, or preset mapping; Polyphone gives control over those settings.

Quality, compatibility, and limitations

OGG Vorbis is usually lossy, so decoding it to WAV does not restore detail removed during encoding. Exporting the WAV as 24-bit or 32-bit cannot recover that information; 16-bit PCM is adequate for many SoundFont instruments, while keeping the original sample rate avoids an unnecessary resampling step.

A single OGG recording normally becomes one sample zone, so notes far above or below its root pitch can sound unnatural. A multisample SF2 made from several recordings at different pitches and velocities gives better results but requires separate WAV files and more zone mapping. SF2 support also varies: some players reject large files, unsupported modulators, stereo samples, or unusual loop settings. Test the saved file in the exact synthesizer or application that will use it.