Video file recorded by Windows Media Center, a program used to play multimedia content and record TV shows; encodes video using MPEG-2 compression and audio using MPEG-1 Layer II or Dolby Digital AC-3 compression; may also include descriptive metadata and digital rights management (DRM) information. The WTV Windows Media Center video format is successor of the DVR-MS Windows Media Center video format and was introduced in Windows 7
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.