Dolby Vision Fallback Compatibility

Dolby Vision fallback uses a compatible base picture when available and otherwise requires supported Dolby Vision interpretation or conversion.

When a Dolby Vision processing route is unavailable, begin with the base signal's defined interpretation. A compatible base can supply another valid presentation; a Dolby Vision-specific base needs its appropriate interpretation or conversion.

Make the playback decision in order

First, can the path read and decode the available video? Container handling and codec support still apply. A compatible light representation is of little use if the player cannot obtain or decode its coded samples.

Second, what does the base represent? The profile and base compatibility identify an HDR10, HLG, SDR, or Dolby Vision-specific arrangement.

Third, can the destination present that interpretation? A supporting HDR10 path can use an HDR10 base. An SDR-only destination needs suitable conversion of that HDR source. HLG requires its own system interpretation.

Finally, which extra information is being used? Dolby Vision metadata and any enhancement contribution belong to the complete presentation path. Their absence or nonuse changes which source information drives the output.

A reference for common base choices

Source example Available base interpretation
Profile 5 Dolby Vision-specific; no ordinary HDR10/SDR base
Profile 7 HDR10
Profile 8.1 HDR10
Profile 8.4 HLG
Profile 9 SDR

Profile 10 uses AV1 with its defined base variants; Profile 20 can add multiview and other processing requirements. Their codec and structure remain inputs to the first decision.

Resolve three plausible sessions

An Emby app receives supported Profile 7 data and uses the HDR10 base. The server may have copied the selected coded video, and the app/display presents HDR10. This is compatible-base use, not automatically an SDR conversion or complete Dolby Vision reconstruction.

Another app receives an HLG-based Profile 8.4 source and uses its HLG presentation. Assigning a PQ interpretation instead would not be that source's defined fallback. The base field decides which relationship is appropriate.

For a Profile 5 source on an incompatible output, simply stripping RPU data leaves the Dolby Vision-specific picture values. A supported converter must interpret those values and prepare another coherent output. If that destination is SDR, HDR-to-SDR processing supplies the brightness, color, and encoding changes.

The source record, actual server delivery, and output mode place each of these sessions on the decision path. They distinguish full processing, compatible-base use, and a newly transformed rendition.

See Also

References