DTS-HD Master Audio
DTS-HD Master Audio is a combined lossless/lossy audio codec created by DTS (formerly Digital Theater Systems), commonly used for surround-sound movie soundtracks on Blu-ray Disc.
Contents
History
It is an extension of DTS' previous DTS Coherent Acoustics codec. Prior to 2004, it had been known as DTS++.[1] Though DTS-HD Master Audio is an optional audio format for Blu-ray Disc format, by 2010, it had steadily become the standard for Blu-ray lossless audio format.[2]
Features
One goal of the DTS-HD Master Audio format was to allow a bit-to-bit representation of the original movie's studio master soundtrack. To accomplish this, DTS-HD Master Audio supports variable bit rates up to 24.5 Mbit/s on a Blu-ray Disc and up to 18.0 Mbit/s for HD DVD. The format supports a maximum of 192 kHz sampling frequency and 24-bit depth samples from 2 to 5.1 channels, and 96 kHz/24bit resolution up to 7.1 channels.[3] DTS-HD is capable of virtually any number of discrete channels but is limited by storage media.[4]
Combined lossless/lossy compression
When played back on devices which do not support the Master Audio or High Resolution extension, it degrades to a "core" track which is lossy.[5]
According to the DTS-HD White Paper,[6] DTS-HD Master Audio contains 2 data streams: the original DTS core stream and the additional "residual" stream which contains the "difference" between the original signal and the lossy compression DTS core stream. The audio signal is split into two paths at the input to the encoder. One path goes to the core encoder for backwards compatibility and is then decoded. The other path compares the original audio to the decoded core signal and generates residuals, which are data over and above what the core contains that is needed to restore the original audio as bit-for-bit identical to the original. The residual data is then encoded by a lossless encoder and packed together with the core. The decoding process is simply the reverse.
AV transport
DTS-HD Master Audio may be transported to AV receivers in 5.1, 6.1 or 7.1 channels, at lossless quality, in one of three ways depending on player and/or receiver support:[6]
- Over 6, 7 or 8 RCA connectors as analog audio, using the player's internal decoder and digital-to-analog converter (DAC).
- Over HDMI 1.1 (or higher) connections as 6-, 7- or 8-channel linear PCM, using the player's decoder and the AV receiver's DAC.
- Over HDMI 1.3 (or higher) connections as the original DTS-HD Master Audio bitstream, with decoding and DAC both done by the AV receiver.
See also
- Dolby TrueHD, a competing audio codec
References
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- ↑ This feature is also offered by unrelated codecs OptimFROG DualStream, WavPack Hybrid and MPEG-4 SLS.[citation needed]
- ↑ 6.0 6.1 Lua error in package.lua at line 80: module 'strict' not found.
