Dolby True HD
An advanced lossless multi-channel audio codec developed by Dolby Laboratories which is intended primarily for high-definition home-entertainment equipment such as Blu-ray Disc and HD DVD. Dolby TrueHD is a lossless audio format, meaning that no audio information is lost when the signal is compressed and uncompressed. It supports up to eight full-range channels of 24-bit/96 kHz audio. Dolby TrueHD competes with DTS-HD Master Audio, a similar lossless codec from Digital Theater Systems sound.
It is the successor to the AC-3 Dolby Digital surround sound codec which was used as the audio standard for DVD discs.