WTV is a format for videos recorded by Windows Media Center where video is encoded by MPEG-2, MPEG-4 or h.264 and audio – by MPEG-1 Layer II or Dolby Digital AC-3. WTV file can contain video, audio, text and other data. The container replaced DVR-MS that was used by previous versions of the Windows program. WTV supports DRM that allows protection of the content by its owner.

This format was originally intended for voice compression and is able to change the bit rates of encoded audio data. AMR is actively used for encoding and decoding voice while its being transmitted over network channels. The format allows one to consider network capacity and adapt it to channel loads. Due to this, the voice quality is practically undiminished.