AVCHD is a video codec designed for recording high definition videos in 720p, 1080i and 1080p modes on such rewritable discs as Blu-Ray and AVCHD, hard disks and memory cards. The AVCHD standard implies using of AVC video compression format, AC3 audio codec and MTS or M2TS file extension. The main feature of the codec is high compression efficiency together with high image quality. But here comes the main flaw – the codec is really heavy for playback.

AU is a file extension for a sound file format belonging to Sun, NeXT and DEC and used in UNIX. The AU file format is also known as the Sparc-audio or u-law fomat. AU files contain three parts: the audio data and text for a header (containing 24 bytes) and an annotation block.