WMA to SOU Converter

Generate raw 8-bit SOU audio from WMA files

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Raw PCM Format

SOU provides bare 8-bit audio from WMA for embedded systems.

Server Encoding

No raw audio tools needed — convert WMA to SOU online.

Bulk Processing

Convert WMA collections to SOU simultaneously.

How to convert WMA to SOU

1

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

2

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

3

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

About formats

WMA (Windows Media Audio) is a family of proprietary audio codecs developed by Microsoft and first released in 1999 as part of the Windows Media framework. Created to compete with MP3 and AAC, WMA Standard uses perceptual coding to deliver what Microsoft claimed was near-CD quality at bitrates as low as 64 kbps — roughly half the data rate MP3 typically needed for comparable results. The codec family grew to include WMA Professional for surround sound and high-resolution audio, WMA Lossless for bit-perfect archival compression, and WMA Voice optimized for spoken content at very low bitrates. Deep integration with Windows, Windows Media Player, and the Zune ecosystem gave WMA a strong distribution advantage throughout the 2000s, and digital rights management (DRM) support made it attractive to online music stores of that era. Encoding and decoding are handled natively by Windows, requiring no third-party software for playback on any Windows machine. Cross-platform support has improved through libraries like FFmpeg and GStreamer, though WMA remains less universally compatible than MP3 or AAC on non-Microsoft devices. The format still appears in legacy media libraries, though newer codecs have largely taken its place for streaming and portable use.
Initial release: 1999
SOU is a raw audio format designation that functions as an alias for unsigned 8-bit PCM data (u8) in the SoX audio processing framework. Files with the .sou extension contain headerless, uncompressed audio samples stored as unsigned 8-bit integers — each byte represents a single amplitude value from 0 to 255, with 128 as the silence midpoint. Because there is no header, playback parameters such as sample rate and channel count must be specified externally. The default assumption is typically mono at 8000 Hz, though the data can represent any rate the recording hardware supported. The u8 encoding that SOU aliases is one of the simplest possible digital audio representations, predating structured audio containers like WAV and AIFF. Raw unsigned PCM was commonly produced by early sound cards and digitizers in the late 1980s and early 1990s, when storage constraints and limited processing power made headerless formats a practical choice. One advantage is absolute simplicity: SOU files can be read by any program capable of basic file I/O, with no parsing of container structures or metadata decoding required — useful for embedded systems, hardware diagnostics, and educational contexts where audio fundamentals are being explored. The format's minimal overhead also means that conversion to any modern container is lossless and instantaneous, since the raw PCM samples can be wrapped in a WAV or AIFF header without any transcoding.
Developer: SoX Contributors
Initial release: 1991

Frequently Asked Questions

Why convert WMA to SOU?

SOU delivers 8-bit unsigned raw PCM that embedded systems and legacy platforms expect. These devices lack WMA decoding capability, so converting to SOU is the required step.

What tools and systems can work with SOU files?

SoX processes SOU on modern computers, and various embedded development environments and legacy audio tools consume raw unsigned PCM data in this format without conversion.

Is SOU essentially the same thing as FSSD?

Yes — SOU and FSSD are both names for 8-bit unsigned integer raw PCM audio. They represent identical data, so files are interchangeable between tools that support either name.

What audio fidelity should I expect from SOU format?

SOU is 8-bit unsigned PCM with a limited dynamic range, designed for basic sound effects and voice prompts in embedded systems — not intended for music or high-fidelity playback.

Can I upload many WMA files and convert them all to SOU?

Yes — upload your entire set of WMA recordings in one session and convertio.tools generates separate SOU files for each, making it efficient to prepare batches for embedded platforms.