AAC (Advanced Audio Coding) is a lossy audio format developed by Dolby and Sony Corporation, AT&T Bell Laboratories, and Fraunhofer IIS. During compression, AAC eliminates unnecessary data, making it smaller and easier to stream or download. Today, Apple devices such as iPhones and iPads are the biggest users of the AAC format.
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MKV is a container format for holding multiple audio, video, picture, and text data such as subtitle tracks. It is similar to other common containers like MP4 and AVI, although MKV is open in the specification. For video contents, MKV uses a .mkv filename extension, .mka for audios, and .mks for subtitles.
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