Convert MIDI to WAV — Free Online Converter

MIDI (.midi) occupies a unique position in music technology as both the oldest and most forward-looking digital music format. At over 40 years old, MIDI remains irreplaceable because no other format separates musical intent from sonic realization so cleanly. A .midi file can be rendered through a 1990s FM synthesis chip, a 2025 neural network audio model, or anything in between — each producing valid but wildly different interpretations of the same musical content.

WAV (Waveform Audio File Format) is the foundational digital audio format — uncompressed PCM stored in a RIFF container. Converting MIDI to WAV performs the irrevocable step from abstract music to concrete sound: the synthesis engine renders every MIDI event into audio samples, and WAV captures the complete result without any compression, processing, or alteration. This is the purest possible recording of a MIDI synthesis session.

Sound designers creating sample libraries render MIDI phrases to WAV because the uncompressed format preserves the complete frequency spectrum and dynamic range of the synthesis output. These WAV samples can then be loaded into samplers, mapped across keyboards, layered, and processed without any codec-introduced artifacts interfering with the creative process.

Mastering engineers receiving MIDI composition renders need WAV as the starting point for their processing chain. EQ, compression, limiting, stereo widening, and loudness normalization all benefit from operating on uncompressed PCM data where every sample is exactly as the synthesizer produced it. No lossy codec artifacts exist to interact unpredictably with mastering processing.

FFmpeg decodes the .midi file's complete event timeline, resolving delta-time events to absolute timestamps using the PPQN resolution and tempo map. The synthesis engine operates at the target sample rate (typically 44.1 or 48 kHz) with the configured bit depth (16 or 24 bits). Each sample frame involves summing all active voice oscillators across all 16 MIDI channels, applying per-voice ADSR envelopes and filters, processing global effects (reverb, chorus from SoundFont presets), and writing the final stereo sample pair. The raw PCM output is framed in a RIFF WAV container: a 12-byte RIFF header, a fmt chunk specifying PCM format with channel count, sample rate, bit depth, and block alignment, and a data chunk containing the interleaved PCM samples.