Convert MOD to FLAC — Free Online Converter

MOD is the seminal tracker music format from the Commodore Amiga, created by Karsten Obarski for the Ultimate Soundtracker in 1987. It fundamentally changed how computer music was made by embedding short 8-bit instrument samples directly in the file alongside pattern-based sequencing data. A typical MOD contains up to 31 samples (drums, bass, leads, pads) and 64-128 rows of note data per pattern across 4 channels, with each note triggering a sample at a specific pitch via Amiga period values. Effect commands (3xx portamento, 4xx vibrato, Cxx volume, etc.) add expressiveness within the constraints. The entire demoscene culture — competitive programming art groups like Future Crew, TRSI, and Fairlight — was built on this format.

FLAC (Free Lossless Audio Codec) by Josh Coalson provides bit-perfect compression of PCM audio, typically reducing file sizes by 40-60% without discarding any information. Converting MOD to FLAC renders the tracker composition into a continuous audio stream through software synthesis, then compresses that stream losslessly. This combination preserves every detail of the rendering while keeping files manageable — making FLAC the ideal format for serious archival of tracker music when cross-platform compatibility matters more than Apple ecosystem integration.

The tracker music preservation community maintains archives of hundreds of thousands of MOD files (the Mod Archive alone hosts over 300,000 modules). While the original files should always be preserved, having rendered FLAC versions serves multiple purposes: they provide consistent reference recordings independent of rendering engine differences, they play on every modern device without special software, and they can be uploaded to lossless music platforms and archives. FLAC's open-source nature and universal support make it the de facto standard for lossless audio archival.

Audiophile listeners who appreciate the raw character of tracker music — the crunchy 8-bit samples, the hard-panned Amiga stereo, the aliasing artifacts that became an aesthetic choice — want to preserve that character without adding lossy compression artifacts on top. FLAC delivers exactly this: the rendered MOD audio, bit-for-bit preserved, playable in foobar2000, VLC, Winamp, MPD, Kodi, and virtually every music player across every platform.

FFmpeg's module decoder (libopenmpt preferred for accuracy, libmodplug as fallback) parses the MOD file structure: the 1084-byte header (20-byte title, 31x30-byte sample descriptors, song length, pattern order table, 'M.K.' or 'M!K!' magic bytes), followed by pattern data and sample data. The renderer processes each pattern row at the configured tempo (default: speed 6, BPM 125 = 50 Hz tick rate from Amiga VBLANK), synthesizing all channels simultaneously with proper effect processing. The resulting PCM stream feeds into FLAC's encoder, which segments the audio into blocks (typically 4096 samples), applies linear prediction (up to 12th order) to model the signal, and entropy-codes the residuals using Rice coding. The output is a standard FLAC stream with STREAMINFO, PADDING, and optional VORBIS_COMMENT metadata blocks.