Fallback to an Embedded Audio Core
Core fallback plays an existing compatible audio component when the full presentation is unavailable.
The selected soundtrack says DTS-HD Master Audio, but an older receiver detects DTS. An existing compatible core can explain this result: the player delivered the part that the receiver understands while omitting the enhancement information.
Core fallback uses already encoded data. It differs from making a new codec version during playback.
Extracting the existing DTS core
A common DTS-HD disc stream has a core and extensions. The core is independently decodable; the appropriate full decoder uses the additional information for its enhanced or lossless presentation.
If the output needs conventional DTS, a supported extraction route can retain the core's coded data. That result has the losses already present in the core, but avoids another lossy encoding generation.
| Route | Origin of the delivered audio |
|---|---|
| Extract existing core | Coded component from the selected stream |
| Choose another soundtrack | Separately stored track/presentation |
| Decode and transcode | New encoded data from reconstructed audio |
A source can remain fully intact in the library while only one compatible component is used in the session.
Describe what the fallback omitted
A core may have fewer channels or lack lossless correction and spatial information used by the full presentation. The receiver's successful DTS decode therefore establishes that a compatible soundtrack arrived, not that the original Master Audio or DTS:X result was reconstructed.
The lossless-correction example in Master Audio shows why the core alone differs from the corrected result.
Establish that a core actually exists
DTS defines extension-only arrangements too. An extraction operation cannot manufacture a missing core from such a stream; it would need another source presentation or a conversion.
The Dolby cases also have different structure. TrueHD can be accompanied by separate/packaged AC-3 compatibility audio, but it does not contain the common DTS-HD-style lossy core. An E-AC-3 independent substream is independent within E-AC-3, not automatically an AC-3 component.
For an Emby playback report, identify the selected source's actual components and the delivered codec. If a decoder/encoder created new AC-3 from the full source, call that transcoding, even if its final label resembles a familiar fallback. Naming the operation accurately explains both the preserved source and the presentation heard.