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MP4 to AU


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Free and unlimited use:

Our service is entirely free and without limits. Use it anytime, anywhere, for as many conversions as you need, without any restrictions.

Audio Size Preview:

Our audio size preview feature provides an estimate of the file size after conversion, regardless of the format. This tool helps users gauge whether the new file size meets their needs and storage capabilities, making it easier to decide on the conversion parameters for formats ranging from compressed to uncompressed audio.

Custom Quality:

Our conversion tool offers customizable options for audio bitrate and sample rate, allowing users to fine-tune the quality of their audio files. Whether you're converting to a format for professional use or casual listening, these settings provide the flexibility to optimize audio quality according to your specific requirements.

Fast conversion:

We value your time. Our efficient service rapidly converts your files to high-quality AU format, reducing waiting times. Experience quick conversions and access your AU files promptly.

Cross-Platform Accessibility: is accessible from any device with an internet connection. Whether on a desktop, tablet, or smartphone, you can convert MP4 to AU seamlessly anytime, anywhere.

Privacy Protection:

Your privacy is our utmost priority. We ensure that your files are never stored on our servers, maintaining the security and confidentiality of your data at all times.

Local Conversion:

For enhanced security, convert your MP4 to AU directly on your device. Our local conversion process prevents your videos from being uploaded to our servers, thus guaranteeing your privacy and the confidentiality of your files, especially crucial for sensitive or personal content.

Audio parameters

Audio Bitrate:

Audio bitrate is a key determinant of audio quality and file size, measured in kilobits per second (kbps). Common bitrate values range from 128 kbps, suitable for standard quality, to 320 kbps for high-quality audio. In professional settings, bitrates can be even higher. Our tool allows you to choose from a variety of bitrate options, enabling you to strike the perfect balance between sound quality and file size based on your specific needs, whether it's for casual listening or high-fidelity audio playback.

Sample Rate:

The sample rate, measured in hertz (Hz), defines how many times the audio is sampled per second. Standard CD-quality audio uses a sample rate of 44.1 kHz, while professional audio recordings often use 48 kHz or higher, up to 192 kHz for high-resolution audio. Our conversion tool lets you adjust the sample rate to suit your requirements, offering the flexibility to choose between standard quality for everyday use and higher rates for detailed, professional-grade audio production.

Introduction to AU Format

Definition of AU

The AU file format is a simple audio format that is commonly used on Unix-based systems and varies in terms of encoding and quality. It is known for its straightforward design and compatibility with various Unix applications.

Flexibility and Compatibility

AU files are versatile and can be used in different environments, supporting a range of codecs and quality levels. This makes them suitable for various applications, from simple notification sounds to more complex audio requirements.

Introduction to MP4 Format

Definition of MP4

MP4, or MPEG-4 Part 14, is a multimedia container format used to store video and audio streams, along with subtitles and images. Widely used for streaming media over the internet, it is compatible with a vast array of digital devices and software.

Broad Compatibility

MP4's compatibility spans a wide range of digital devices and playback software, making it a universal choice for video storage and streaming.

Efficient Compression

MP4 is notable for its efficient compression capabilities, allowing high-quality video and audio content to be stored in compact file sizes, facilitating easier online streaming and downloading.

What Happens When Converting MP4 to AU

Audio Extraction

The conversion process involves extracting the audio component from the MP4 file. This step isolates the audio data for conversion into the AU format.

Format Conversion

Once extracted, the audio is converted to the AU format, adapting it to the simpler, Unix-based audio format while maintaining the integrity of the original audio as much as possible.

Quality and Compatibility

While converting to AU, the aim is to retain as much of the original audio's quality as is feasible, ensuring the resulting file is compatible with the intended applications and systems.

Considerations When Converting MP4 to AU

File Size and Quality

Depending on the chosen settings for the AU format, file size and quality can vary. It's important to select the appropriate codec and quality settings to balance these factors according to your needs.


While AU files are highly compatible with Unix-based systems, it's important to ensure that your target device or software supports the AU format.

Privacy and Security

For MP4 files containing sensitive information, choose a conversion service like that respects your privacy. Our process ensures that conversions are carried out on your device, preventing data from being uploaded to external servers and maintaining confidentiality throughout the conversion process.

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