Extract text from Hidden Markov Model audio files (HTK)
To convert HTK audio files to another format, you need HTK Toolkit or other Audio software.
To convert other file formats to the "Acoustic Feature File" file type, you need software like HTK Toolkit or a similar tool.
The .HTK file format stores specialized audio data or extracted acoustic features (such as Mel-Frequency Cepstral Coefficients) used primarily by the Hidden Markov Model Toolkit (HTK). Researchers and data scientists use these files to train machine learning models for speech recognition and voice synthesis.
These files are highly specialized and notoriously frustrating for general users. The format relies on a proprietary header structure and often contains numerical parameter matrices instead of standard sound waves. Consequently, .HTK files exceed the capabilities of standard media players; they will not open in VLC, iTunes, or web browsers. They typically require command-line processing via the original HTK binaries developed by Cambridge University.
If the .HTK file contains an actual acoustic waveform, it should be converted to WAV or FLAC to restore compatibility with consumer audio software. If it contains mathematical feature vectors, converting it to CSV or TXT is necessary to view the raw data.
Standard online converters routinely fail to process .HTK files because they lack the niche academic libraries required to parse HTK's custom headers. This file format is difficult to open or convert because often only the original HTK software can properly read or export the structured data. If our analysis detects a supported underlying raw audio stream, viewing or conversion may still be possible.
Convert.Guru analyzes your HTK file, detects the exact format, and lets you read the text inside.
If you want to convert HTK file to MP3, WAV, AAC, FLAC, OGG, WMA, M4A, AIFF, OPUS, ALAC, APE or WV, you can use HTK Toolkit or similar software from the "Speech Recognition Acoustic Data" category. In the File menu, look for Save As… or Export….
To convert MIDI, AAC, TTA, AU, WV, DTS, MID, FLAC, RA, MP3, PCM or WAV files to HTK, try HTK Toolkit or another comparable tool in the "Speech Recognition Acoustic Data" category.
The history of Convert.Guru began over 25 years ago in California with Tom Simondi’s file-format database. A former contributor to Space Shuttle development and a software pioneer of the 1980s, Simondi established a trusted resource for file type analysis that was even referenced by Microsoft Windows XP. Today, we use modern technology to process and convert thousands of file formats while continually improving our HTK converter.