Convert Standard MIDI File (.midi) to Free Lossless Audio Codec (.flac) online for free. Fast, secure audio conversion with no watermarks or registration.
Upload your .midi file by dragging it into the upload area or clicking to browse.
Choose your output settings. The default settings work great for most files.
Click Convert and download your .flac file when it's ready.
MIDI (.midi) files are the musical equivalent of source code — editable, lightweight, and infinitely flexible. A MIDI file of Beethoven's entire Fifth Symphony might occupy 60 KB, encoding every note, dynamic marking, and tempo change as discrete events. The .midi extension appears frequently in Linux distribution music packages (where Timidity++ or FluidSynth provides system-wide MIDI playback), in open-source game soundtracks, and in academic computational music research datasets.
FLAC (Free Lossless Audio Codec) is the universal open-source lossless audio standard, supported on every major platform including Windows, macOS, Linux, Android, and modern iOS. Converting MIDI to FLAC renders the symbolic music through software synthesis and preserves the complete audio output without any lossy compression, making it the ideal archival and audiophile format for MIDI renders.
Open-source music projects — Linux distribution boot sounds, game soundtracks for FOSS games, creative commons music libraries — frequently start as MIDI compositions. When these projects need to ship audio rather than MIDI, FLAC is the natural choice: patent-free, lossless, and universally supported. It aligns with the open-source philosophy that typically surrounds .midi-based workflows.
Audiophile listeners who want to hear MIDI compositions at their absolute best should render to FLAC. Unlike lossy codecs that discard inaudible frequencies (psychoacoustic masking), FLAC preserves the complete spectrum of the synthesis output. When combined with a high-quality SoundFont, FLAC MIDI renders can be genuinely impressive — indistinguishable from the direct synthesis output.
FFmpeg processes the .midi file through its SMF decoder, constructing a timeline of MIDI events with absolute timestamps derived from the tempo map and PPQN division. The synthesis engine processes these events through a SoundFont bank: program changes select instrument patches, note-on events trigger sample playback with velocity-sensitive parameters (filter cutoff, amplitude, sample offset), and continuous controllers modulate the sound in real time. The resulting PCM audio is compressed by FLAC's encoder pipeline: decorrelation (mid-side for stereo), linear prediction (up to 32nd order), residual encoding, and Rice/Golomb entropy coding — all completely reversible upon decoding.
FLAC is mathematically lossless — the decoder produces PCM identical to the encoder input. Synthesized MIDI audio typically achieves 40-50% FLAC compression ratios, slightly better than live recordings because synthesis output has lower noise floors and more structured waveform patterns. The quality perceived by the listener depends entirely on the SoundFont. For audiophile-oriented renders, use SoundFonts built from high-resolution (96 kHz/24-bit) instrument recordings with natural room ambience and articulation switching for the most convincing results.
| Device | MIDI | FLAC |
|---|---|---|
| Windows PC | Partial | Partial |
| macOS | Partial | Partial |
| iPhone/iPad | Partial | Partial |
| Android | Partial | Native |
| Linux | Partial | Native |
| Web Browser | No |
Resolution: N/A
Bitrate: 320 kbps
OGG Vorbis preferred
Resolution: N/A
Bitrate: 256 kbps
AAC format required
Resolution: N/A
Bitrate: 128 kbps
Lossless FLAC/WAV for best quality
Resolution: N/A
Bitrate: 128 kbps
MP3 mono for spoken word
MIDI to FLAC provides lossless, patent-free audio from symbolic music data. It is the definitive archival format for MIDI renders in open-source, audiophile, and research contexts.
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| No |
| 特性 | MIDI | FLAC |
|---|---|---|
| 全称 | Standard MIDI File | Free Lossless Audio Codec |
| 扩展名 | .midi | .flac |
| 最适合 | Musical data format | Lossless compression |