SHN to GSM Converter

Compress Shorten to GSM mobile voice codec online

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Global Voice

GSM 06.10 powers mobile voice worldwide — lossless SHN gives telephony the cleanest speech input.

Ultra-Compact

GSM at 13 kbps is extremely small — ideal for telephony bandwidth constraints.

Cloud Encoding

No GSM libraries needed — our servers convert SHN to GSM through your browser.

How to convert SHN to GSM

1

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

2

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

3

Let the file convert and you can download your gsm 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 While FLAC eventually superseded Shorten with better compression, seeking support, and embedded metadata, SHN retains historical importance and extensive live music archives in the format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
GSM 06.10 (Full Rate) is the foundational speech codec of the Global System for Mobile Communications standard, ratified by ETSI in 1991 and deployed across hundreds of cellular networks worldwide. Operating at a fixed 13 kbit/s, the algorithm applies Regular Pulse Excitation with Long-Term Prediction (RPE-LTP) to compress 20 ms frames of 8 kHz mono speech into just 33 bytes each. This approach models the vocal tract as a linear predictive filter, encodes the excitation signal, and leverages pitch periodicity for further reduction — tuned to deliver intelligible voice under the bandwidth constraints of early digital mobile channels. The codec powers not only GSM telephony but also many VoIP applications, voicemail systems, and IVR platforms that benefit from its low bitrate. Three concrete advantages stand out. First, extraordinary compression: one minute of speech fits in roughly 100 KB, enabling efficient storage and transmission. Second, universal tooling — libraries such as libgsm and SoX handle encoding and decoding on every major platform. Third, a royalty-free patent landscape that has encouraged adoption across open-source telephony projects like Asterisk and FreeSWITCH.
Initial release: 1991

Frequently Asked Questions

Why convert SHN to GSM?

Telephony platforms, IVR systems, and voice messaging need GSM 06.10 audio. Lossless SHN guarantees the cleanest voice input for GSM encoding.

How do I play GSM audio files?

VLC, SoX, Asterisk PBX, and most telephony software handle GSM natively. For casual listening, convert GSM to WAV or MP3 with any audio converter.

Is GSM suitable for music or only voice?

Voice only — GSM 06.10 encodes at 8 kHz mono and 13 kbps, optimized strictly for speech clarity. For music, choose MP3, FLAC, or OGG instead.

How compact are GSM files compared to SHN?

Very compact — GSM at 13 kbps produces files that are a tiny fraction of the original lossless SHN. Ideal for telephony with limited bandwidth.

What happens to my SHN files after conversion?

SHN uploads are permanently removed from servers as soon as conversion completes. GSM output is automatically purged within 24 hours for data protection.