SHN to HCOM Converter

Encode Shorten as Mac HCOM Huffman format online

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Mac Vintage

Create HCOM from lossless SHN — both use lossless compression, with HCOM native to classic Macintosh.

Lossless Chain

Both SHN and HCOM are lossless — audio quality fully preserved through the conversion.

No Mac Needed

Generate HCOM from any OS through your browser — no vintage hardware required.

How to convert SHN to HCOM

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose hcom or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your hcom file right afterwards

About formats

Shorten (SHN) is a lossless audio compression codec created by Tony Robinson at SoftSound and first published in 1993, making it one of the earliest practical lossless compressors. The algorithm uses linear prediction to estimate each sample from predecessors, then encodes residuals with Huffman or Golomb-Rice codes. Compression ratios typically fall between 2:1 and 3:1, with the guarantee that decoded output is bit-identical to the original. Shorten gained cultural significance in the late 1990s as the preferred format for trading live concert recordings online — communities like etree.org built entire distribution networks around SHN files, and bands like the Grateful Dead and Phish tacitly endorsed the practice. One advantage was the format's simplicity: encoding and decoding ran fast even on modest Pentium-era hardware. Another strength was deterministic output — the same input always produced the same bytes, making checksums reliable for verifying integrity across thousands of traders. While FLAC eventually superseded Shorten with better compression, seeking support, and embedded metadata, SHN retains historical importance and extensive live music archives in the format still circulate today.
Initial release: 1993
HCOM is a Huffman-coded audio format from the early Macintosh era, designed to shrink digitized sound for distribution on floppy disks and bulletin board systems when storage was precious and modems were slow. The encoder takes 8-bit unsigned PCM input, computes a frequency table of sample-delta values, and builds an optimal Huffman tree that replaces common deltas with short bit sequences. Compression ratios of 2:1 or better were typical for speech recordings, a meaningful saving when a 3.5-inch floppy held only 800 KB. Files were distributed as Macintosh resource forks and played through utilities like SoundApp and the BinHex ecosystem that defined Mac software exchange in the late 1980s. The format supported sample rates up to 22.255 kHz, matching the output capabilities of original Macintosh sound hardware. Tools such as SoX retain HCOM decoding support, ensuring that archived recordings remain accessible decades later. HCOM holds three practical advantages for preservation work: lossless compression that recovers the original samples exactly, a self-contained Huffman table embedded in each file for dependency-free decoding, and historical prevalence across thousands of vintage Mac sound archives.
Developer: Apple Computer
Initial release: 1985

Frequently Asked Questions

What is HCOM?

HCOM is a Huffman-compressed Mac sound format from classic Mac OS — lossless compression for audio data.

Why convert SHN to HCOM?

Classic Mac projects need HCOM audio. Both SHN and HCOM use lossless compression, preserving quality.

What opens HCOM?

SoX, classic Mac emulators, and retro computing tools support HCOM.

Is quality preserved?

HCOM uses lossless Huffman coding — quality is fully preserved from lossless SHN source.

Is it private?

SHN uploads are deleted immediately. HCOM results are removed within 24 hours.