IMA to SOU Converter

Encode IMA audio as SOU 8-bit raw audio online

Drop files here. 1 GB maximum file size or Sign Up
to
Facebook Amazon Microsoft Tesla Nestle Walmart L'Oreal

Format Freedom

Transform IMA recordings into SOU — bringing headerless audio into a format with real-world usability.

File Privacy

Your IMA files are erased immediately after processing. SOU results are cleaned from our servers within 24 hours.

Any Platform

Convert from any device with a browser — desktops, laptops, tablets, and smartphones all work perfectly.

How to convert IMA 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

IMA ADPCM (Adaptive Differential Pulse-Code Modulation) is a compact audio coding standard published by the Interactive Multimedia Association in 1992, addressing the need for a lightweight, royalty-free compression scheme suitable for early multimedia PCs and embedded devices. The algorithm encodes each sample as a 4-bit nibble representing the quantized difference from the previous sample, while an adaptive step-size table adjusts dynamically to track signal amplitude — delivering a fixed 4:1 compression ratio over 16-bit PCM. Decoding requires only an integer multiply-add per sample and a small lookup table, so even modest 1990s CPUs could decompress in real time without dedicated DSP. The format became deeply embedded in the multimedia landscape: Microsoft adopted it as a standard ACM codec for WAV files, game engines relied on it for sound effects, and telephony equipment used it for voice storage. Its advantages are enduring: predictable 4:1 size reduction simplifies buffer allocation in constrained environments, the decode path runs on 8-bit microcontrollers, and the open specification made IMA ADPCM one of the most broadly implemented audio codecs in computing history.
Initial release: 1992
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 IMA to SOU?

IMA ADPCM is headerless and hard to use outside embedded systems. SOU provides a proper format with broad compatibility.

What applications open SOU files?

SOX and embedded systems can handle SOU files. Most are available as free downloads for major operating systems.

How is the SOU audio quality?

SOU provides good quality at standard settings. The output clarity depends on the original IMA recording quality.

How fast is the conversion?

Processing is fast — IMA files are lightweight and SOU encoding completes in seconds on our server hardware.

Are my files kept private?

Your IMA files are erased after conversion completes. SOU downloads are purged from our servers within 24 hours automatically.

Does this work on mobile?

Yes. The converter runs in any browser — smartphones, tablets, and desktops all work for IMA to SOU conversion.