SHN to HTK Converter

Encode Shorten audio as HTK speech research online

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Specialized Output

Generate HTK 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 HTK conversion through your browser.

Secure Files

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

How to convert SHN to HTK

1

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

2

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

3

Let the file convert and you can download your htk 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 While FLAC eventually superseded Shorten with better compression, seeking support, and embedded metadata, SHN retains historical importance and extensive live music archives in the format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
HTK is the native waveform container for the Hidden Markov Model Toolkit, a software suite developed at Cambridge University's Engineering Department for speech recognition research. First distributed in 1993, HTK rapidly became a reference platform in computational linguistics labs worldwide, and its file format followed suit. Each file stores a sequence of parameter vectors or raw samples prefixed by a 12-byte header specifying the number of frames, the frame period in 100 ns units, the byte count per frame, and a type code indicating the data kind — options range from waveform PCM to Mel-frequency cepstral coefficients and filter-bank energies. This versatility lets a single container carry both source audio and extracted features without changing parsers. The deliberately minimal header avoids alignment padding or optional chunks, making the format trivial to read from C, Python, or MATLAB with a few lines of binary I/O. Three advantages underpin HTK's lasting relevance: tight integration with the HTK training and recognition pipeline, deterministic byte layout that eliminates parser ambiguity, and widespread adoption in academic corpora.
Initial release: 1993

Frequently Asked Questions

What is HTK?

HTK is a specialized audio format — the format for the Hidden Markov Model Toolkit in speech recognition research.

Why convert SHN to HTK?

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

What handles HTK?

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

Is quality maintained?

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

Is the conversion secure?

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