AU to IMA Converter

Fast online AU to IMA audio conversion tool

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Faithful Conversion

Audio integrity is preserved when moving from AU to IMA. The converter handles sample rates and bit depths with care.

Fast Results

The AU to IMA conversion engine is optimized for speed. Most audio files are processed and ready to download within seconds.

Browser-Based Tool

No software to install — convert AU to IMA directly in Chrome, Firefox, Safari, or Edge. Open the page and start converting.

How to convert AU to IMA

1

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

2

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

3

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

About formats

AU is an audio file format introduced by Sun Microsystems for its Unix workstations and the NeXT platform. It features a minimal 24-byte header specifying data offset, size, encoding type, sample rate, and channel count, followed by the audio payload. AU supports numerous encodings, including uncompressed linear PCM at various bit depths, mu-law and A-law companding (logarithmic compression used in telephone systems), and several ADPCM variants. This versatility made AU a workhorse across early Unix environments, web audio (Java applets defaulted to AU), and telephony applications. One advantage is simplicity: the compact header and straightforward structure make it trivial to parse, generate, and stream programmatically. The built-in mu-law option provides another benefit, delivering reasonable voice quality at just 8 KB per second — half the rate of 16-bit uncompressed audio — invaluable when storage and bandwidth were scarce. Although modern formats have largely supplanted AU in consumer applications, it retains a foothold in scientific computing and audio processing pipelines where minimal overhead and reliable cross-platform behavior are valued.
Developer: Sun Microsystems
Initial release: 1992
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

Frequently Asked Questions

Why convert AU to IMA?

Since AU is a dated Sun Microsystems format, moving to IMA brings your audio into a modern, widely recognized container.

How do I open a IMA recording?

Use SoX, Audacity, IMA-compatible audio processors to play or edit IMA recordings. These tools offer reliable compatibility with the format.

Will I lose audio quality in the conversion?

Quality depends on the codec. If IMA uses lossy encoding, minor data loss occurs. Lossless targets preserve the original AU audio faithfully.

How many AU files can I convert in one go?

Upload as many AU files as you need and convert them to IMA simultaneously. The batch feature handles multiple files efficiently.

Are my AU uploads kept private?

Yes. Uploaded AU files are deleted right after conversion, and the IMA output is removed from our servers within 24 hours automatically.

AU to IMA Quality Rating

3.0 (1 votes)
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