WMV to SPH Converter

Reliable WMV to SPH conversion — works in any browser

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Rapid Processing

Converting WMV to SPH is fast — cloud servers handle the heavy lifting so you get results in moments.

Data Safety First

Files are processed securely and deleted after conversion. Nothing lingers on servers — your privacy is fully protected.

Cloud-Powered Engine

The entire conversion runs on remote servers — your device stays fast and unburdened during the WMV to SPH process.

How to convert WMV to SPH

1

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

2

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

3

Let the file convert and you can download your sph file right afterwards

About formats

WMV (Windows Media Video) is a family of video codecs and associated file format developed by Microsoft, first introduced in 1999 as part of the Windows Media framework. The format encompasses several codec generations, from the original WMV 7 through WMV 9 (also standardized as VC-1 by SMPTE under the 421M specification). WMV files are typically contained within the ASF (Advanced Systems Format) wrapper and use the .wmv extension to indicate video content. WMV 9/VC-1 achieved compression efficiency comparable to early H.264 implementations, delivering good visual quality at moderate bit rates and earning adoption for HD DVD and Blu-ray disc content as an approved codec. The format was deeply integrated into the Windows operating system, Windows Media Player, and server-side streaming infrastructure, making it a natural choice for enterprise media delivery, corporate training videos, and Windows-centric web content throughout the 2000s. WMV supports features including interlaced video, multiple bit rate encoding for adaptive streaming, and digital rights management through Windows Media DRM. The Silverlight platform also used WMV as its primary video format for rich internet applications and streaming services. While the industry has largely moved to H.264 and HEVC for most applications, WMV remains present in legacy enterprise content management systems, archived media libraries, and workflows tied to the Windows Media ecosystem.
Developer: Microsoft
Initial release: 1999
SPH is the file extension for audio stored in the NIST SPHERE (SPeech HEader REsources) format, a standard created by the U.S. National Institute of Standards and Technology around 1990. Built for speech research, SPH files carry a 1024-byte ASCII header packed with metadata — database identifiers, channel counts, sample rates, byte ordering, and compression type — making every recording self-describing. The underlying audio is typically 16-bit linear PCM sampled at 16 kHz, though other configurations are permitted. Researchers at NIST, DARPA, and universities worldwide rely on SPH for distributing speech corpora such as TIMIT, Switchboard, and the LDC collections that underpin modern automatic speech recognition systems. A key advantage is that the human-readable header lets scripts parse recording metadata without binary decoding. The format's strict standardization also eliminates ambiguity when sharing datasets across institutions and platforms. Because SPH files store uncompressed PCM, they preserve full audio fidelity — critical when training acoustic models where even small artifacts can skew results.
Initial release: 1990

Frequently Asked Questions

Why convert WMV to SPH?

Since WMV has poor Mac, Linux, and mobile device support, converting to SPH gives you speech recognition training use across more platforms.

How do I open a SPH file?

SPH opens easily in NIST/SPHERE tools, HTK toolkit, or SoX. Just double-click the file or drag it into the player of your choice.

Does the conversion work on mobile?

It does. Convertio.tools works in any modern mobile browser — upload your WMV, convert to SPH, and download directly on your phone.

Can I adjust the output bitrate?

Yes — set the desired bitrate before converting. Lower bitrates produce smaller files, while higher bitrates preserve more audio detail.

How long does the conversion take?

Conversion speed depends on the WMV file size and chosen quality settings. Most files process within seconds to a couple of minutes.

What devices can play SPH?

SPH playback requires compatible software on your desktop or laptop. Check the recommended apps above to find the right player for your system.