WMA to NIST Converter
Create NIST SPHERE speech files from WMA audio
Speech Research
NIST SPHERE is the standard for ASR — convert WMA for research pipelines.
Corpus-Ready
Generate SPHERE with correct headers for speech recognition training.
Online Processing
No toolkit needed — convert WMA to NIST in your browser.
How to convert WMA to NIST
Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.
Choose nist or any other format you need as a result (more than 200 formats supported)
Let the file convert and you can download your nist file right afterwards
About formats
Frequently Asked Questions
NIST SPHERE is the mandatory input format for major speech recognition toolkits like Kaldi and HTK. These pipelines reject WMA entirely, so converting to SPHERE is required before any training or evaluation.
Kaldi, HTK, CMU Sphinx, NIST evaluation scoring tools, and many university research frameworks expect SPHERE input. The format is the de facto standard for speech corpus distribution worldwide.
Yes — NIST, SPH, and SPHERE all refer to the same format: SPeech HEader REsources developed by NIST. The file extension may vary (.nist, .sph) but the internal structure is identical.
NIST SPHERE stores PCM audio, so the decoded WMA content is transferred without additional compression. Speech recognition accuracy depends on source quality, which is preserved during conversion.
Yes — upload your full set of WMA recordings and Convertio produces a NIST SPHERE file for each simultaneously. Download individually or as a single archive for immediate use in your research pipeline.