DTS-HD Master Audio

DTS-HD Master Audio uses lossless extension information to reconstruct the encoded source audio exactly.

How can a soundtrack with a lossy DTS core give a lossless result? DTS-HD Master Audio includes the information needed to correct or reconstruct what the compatible core alone does not preserve.

In a common core-plus-lossless-extension arrangement, the full decoder combines the required components. A core-only decoder plays a different, compatible result.

Reconstruct the exact difference

Use an illustrative pair of samples:

Source Core reconstruction Exact correction Full result
1,020 1,001 +19 1,020
1,025 1,028 −3 1,025

The core's errors do not remain in the final result when the additional information restores the exact source values. This table models the lossless-correction principle; DTS's XLL processing and channel/frequency organization are more elaborate than two literal correction numbers.

A lossy enhancement that quantizes its correction can merely reduce an error. The full Master Audio reconstruction must retain the information required for the exact encoded audio result. That is the distinction from DTS-HD High Resolution Audio.

Choose the component set

Components decoded Audio result
Existing core alone Lossy compatible presentation
Required core and lossless extension information Full lossless presentation
Supported extension-only lossless stream Lossless presentation without a legacy core fallback

The standard allows lossless streams without a backward-compatible core. For those, an older destination cannot obtain a missing core simply by asking to “strip HD.” The actual stream structure controls the available fallback.

A core and extensions can also appear as one container soundtrack. They need not be separately selectable language tracks.

Place output after reconstruction

Once the full presentation has been decoded, the player can output PCM. The receiver sees sample values rather than a request to decode Master Audio, so its input label can change to PCM without a lossy conversion.

If a receiver instead gets an extracted core, it decodes the lossy compatible presentation. If the server decodes and re-encodes another codec, there is a new encoding generation. Those three routes can be distinguished by their actual delivered components.

For an Emby source, this explains why “DTS-HD Master Audio” in the library and “DTS” or “PCM” downstream require a route trace rather than a verdict based on either label alone.

DTS:X can add immersive information in a compatible delivery context. Preserving the lossless audio values and passing the required spatial instructions to an immersive renderer are additional, distinct jobs in that trace.

See Also

References