true high definition (audio codec) (TrueHD)

Dolby TrueHD is a lossless audio compression developed by Dolby specifically for the reproduction of high quality surround sound. Dolby TrueHD, which is based on MLP, Meridian Lossless Packing, lossless compression, is used in DVD-Audio, HD-DVDs and HDTV, and can optionally be used in Blu-Ray discs.

Compared to MLP, it features a higher channel count and higher sampling frequencies. Dolby TrueHD is multi-channel and can carry more than 16 discrete audio channels, with eight channels needed for a surround sound 7.1. The sampling frequency is 96 kHz; if the number of channels is lower, the sampling rate can be doubled to 192 kHz. The sampling depth is 24 bits per sample and the data rates range up to 18 Mbit/s.

In a Dolby TrueHD data stream, 14 discrete audio channels can be transmitted. In addition to the audio data, the TrueHD data stream also contains metadata of the program information or important information about the audio features. In addition to the metadata, Dolby TrueHD also offers a dynamics control with which the volume and dynamics are adjusted to the needs.