AU to GSRT Converter

Online tool to convert AU audio into GSRT

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No Installation

The AU to GSRT converter runs entirely in your web browser. No plugins, no downloads, no setup — just open and go.

Bulk Conversion

Convert an entire folder of AU recordings to GSRT at once. Just upload all files and let the batch converter handle the rest.

Privacy First

All AU files are erased right after processing. Converted GSRT results are automatically purged within 24 hours.

How to convert AU to GSRT

1

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

2

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

3

Let the file convert and you can download your gsrt 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
GSRT is a purpose-built ringtone format developed by Grandstream Networks for its line of IP phones and VoIP endpoint devices. Each file begins with a fixed-size header identifying sample rate (typically 8 kHz or 16 kHz), bit depth, and payload length, followed by PCM or mu-law encoded audio data optimized for the small speakers found in desk phones. The design prioritizes minimal decode complexity — Grandstream handsets run on embedded processors with limited memory, so the format avoids transform stages or complex bitstream parsing. Ringtones are usually provisioned through a web management interface or a centralized configuration server, letting IT administrators push branded audio to an entire fleet of phones at once. Although GSRT occupies a narrow niche within enterprise VoIP telephony, its straightforward binary layout means conversion tools can map the payload directly to WAV with minimal effort. Key advantages include rock-solid playback reliability on Grandstream hardware, negligible latency from file read to speaker output, and seamless integration with the provisioning ecosystem for company-wide ringtone deployment.
Initial release: 2002

Frequently Asked Questions

Why convert AU to GSRT?

AU is a legacy UNIX format with limited software support today. Converting to GSRT ensures broader playback compatibility.

What opens GSRT audio?

Open GSRT with Grandstream IP phones, SoX, audio converters. These applications provide full playback and editing support for the format.

How is audio fidelity handled during conversion?

The converter preserves maximum fidelity. If GSRT is lossless, no data is discarded. Lossy codecs apply minimal perceptible compression.

Does the converter support batch AU conversion?

Absolutely. You can upload a batch of AU files and convert them all to GSRT together, saving significant time on large collections.

Are my AU uploads kept private?

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