This highlights the primary audio track. Dolby TrueHD is an advanced, lossless multi-channel audio codec.

What are you using (e.g., Nvidia Shield, Apple TV, PC, Smart TV app)?

: This denotes Dolby TrueHD, an advanced, lossless audio codec. The "5.1" signifies six channels of sound: three front channels (left, center, right), two surround channels (left, right), and one low-frequency effects channel (subwoofer). Because it is lossless, it delivers studio-grade theater sound identical to the original master mix.

(Dolby TrueHD) is an advanced, lossless multi-channel audio codec. It delivers sound that is identical to the studio master tape.