TrueHD

Dolby TrueHD is a lossless multichannel audio codec developed by Dolby Laboratories for high-definition home entertainment. It provides up to eight discrete channels (7.1) of audio, with support for 24-bit samples and sample rates up to 192 kHz, though many releases use 48 or 96 kHz.

TrueHD uses Meridian Lossless Packing (MLP) as its compression algorithm. The encoded bitstream on Blu-ray Discs or HD DVD stores compressed audio data; a Dolby TrueHD decoder reconstructs a multi-channel PCM stream without perceptible loss. The codec is designed to deliver bit-for-bit identical audio to the original studio master when decoded.

Within Blu-ray and HD-DVD players, TrueHD tracks are commonly included alongside other formats such as Dolby Digital Plus or DTS-HD Master Audio. Playback requires a device that can decode TrueHD or pass the signal through to a compatible decoder via HDMI. When not supported, players may downmix to stereo or downsample.

TrueHD was introduced in the mid-2000s as part of the high-definition disc specifications and has since been widely used on Blu-ray titles. It is one of several lossless audio options for HD media, alongside DTS-HD Master Audio. Unlike some streaming formats, TrueHD is optimized for physical media playback with high bandwidth.