SHN to SLN Converter

Encode Shorten audio as raw SLN for Asterisk online

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Specialized Output

Generate SLN from pristine lossless SHN source — clean audio for your specific application needs.

Online Processing

No specialized tools needed — our servers handle the entire SHN to SLN conversion through your browser.

Secure Files

SHN uploads are erased immediately. SLN outputs are purged from servers within 24 hours.

How to convert SHN to SLN

1

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

2

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

3

Let the file convert and you can download your sln 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 While FLAC eventually superseded Shorten with better compression, seeking support, and embedded metadata, SHN retains historical importance and extensive live music archives in the format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
SLN (Signed Linear) is a headerless raw audio format storing 16-bit signed linear PCM samples at 8000 Hz mono, most closely associated with Asterisk) — the open-source PBX framework developed by Digium (now Sangoma Technologies). Within Asterisk, SLN serves as the native internal audio representation: every codec transcoding operation passes through signed linear as an intermediate step. This makes SLN the backbone of Asterisk's codec translation architecture. The format contains nothing but raw samples — no headers, no metadata, no framing — so parameters must be known in advance. While this lack of self-description might seem limiting, it is actually an advantage in telephony where sample format is fixed by convention and every overhead byte matters across thousands of simultaneous channels. The 8000 Hz rate aligns with the G.711 standard for traditional telephony, capturing the full 300-3400 Hz voice band. Asterisk also supports extended variants (sln16, sln32, sln48) for wideband audio. SLN files require no decoding — just direct memory mapping — making them ideal for real-time mixing, conferencing, and prompt playback in high-density VoIP environments.
Initial release: 1999

Frequently Asked Questions

What is SLN?

SLN is a specialized audio format — the raw signed linear audio native to Asterisk PBX telephony systems.

Why convert SHN to SLN?

Specific applications require SLN files. Lossless SHN provides clean, artifact-free source material for the conversion.

What handles SLN?

Specialized tools, SoX, and targeted professional software support SLN audio processing and playback.

Is quality maintained?

Starting from lossless SHN ensures no prior compression artifacts — output quality depends on SLN format capabilities.

Is the conversion secure?

SHN uploads are deleted immediately after conversion. SLN results are removed from servers within 24 hours.