AACäänikoodekin

AACäänikoodekin, often referred to as AAC (Advanced Audio Coding), is a patented lossy digital audio compression and audio coding standard. It was developed by the Fraunhofer IIS, Dolby Laboratories, AT&T Labs, and Bell Labs as a successor to the MP3 format. AAC is designed to provide higher fidelity audio at lower bitrates compared to MP3, meaning it can achieve better sound quality with smaller file sizes.

The AAC format employs a variety of advanced audio coding techniques. These include improved perceptual modeling, which better identifies and discards sounds that are less likely to be perceived by the human ear. It also utilizes techniques like temporal noise shaping and uses a more efficient Huffman coding scheme than MP3. AAC supports a wide range of sampling rates and channel configurations, including mono, stereo, and multi-channel surround sound.

AAC is widely used across various platforms and devices. It is the standard audio format for Apple's iTunes Store, iOS devices, and YouTube. Many other streaming services and digital broadcasting systems also utilize AAC. The format is available in several profiles, such as AAC-LC (Low Complexity), HE-AAC (High-Efficiency AAC), and HE-AACv2, each offering different trade-offs between compression efficiency and audio quality. While widely adopted, AAC is a proprietary format, meaning licensing fees may apply for its implementation.