· Remux Doctor

How to tell if a file is Dolby Vision profile 7 or 8, and whether it has a FEL or MEL

What Dolby Vision profiles 7 and 8 mean, how to read them in MediaInfo, and how to find out whether a profile 7 remux has a full or minimal enhancement layer.

If you collect 4K Blu-ray remuxes, you’ll keep running into the same questions: is this file profile 7 or profile 8, and if it’s profile 7, is the enhancement layer “FEL” or “MEL”? They matter, because they decide what you can safely do with the file. Here’s what they mean and how to check.

Profile 7: what’s on UHD Blu-ray

UHD Blu-ray discs with Dolby Vision use profile 7. It’s a dual-layer format:

  • a base layer (BL), which is an ordinary HDR10 picture,
  • an enhancement layer (EL), a second, smaller video stream, and
  • the RPU, the Dolby Vision dynamic metadata that tells the display how to map each scene.

Profile 8: single layer

Profile 8.1 keeps the HDR10 base layer and the RPU but has no enhancement layer. It’s a single video stream, which is why people often convert profile 7 remuxes to 8.1.

FEL vs MEL

Not every enhancement layer is equal.

  • A minimal enhancement layer (MEL) carries no extra picture detail. In practice the picture is the base layer plus the RPU, so dropping the layer loses nothing that matters.
  • A full enhancement layer (FEL) can carry real extra picture information, such as additional bit depth or brightness detail over the base layer. Dropping it removes that for good.

Some FELs barely differ from the base layer and some add a lot. That’s why it’s worth knowing which you have before you convert anything.

Checking with MediaInfo

MediaInfo shows the HDR format line for the video track. You’ll see something like:

  • Dolby Vision, Version 1.0, Profile 7.6, dvhe.07.06, BL+EL+RPU for a profile 7 dual-layer file, or
  • Dolby Vision, Version 1.0, Profile 8.1, dvhe.08.06, BL+RPU for profile 8.1.

What MediaInfo won’t tell you is whether a profile 7 enhancement layer is minimal or full. Working that out by hand means extracting the layer and inspecting the RPU with a tool such as dovi_tool, then looking at the values across the film.

Checking with Remux Doctor

Remux Doctor reads the file and explains it in plain English: the Dolby Vision profile, the HDR format of the base layer, and the audio and subtitles, with the raw details one click away. For profile 7 files, it samples the enhancement layer so you can see whether it’s minimal or full before you change anything.

Drop in a whole folder and the library view gives you a breakdown of Dolby Vision profiles across everything, so you can see at a glance how many profile 7 files you have and which ones have a full layer.

Examining files and sampling enhancement layers is free. If you then want to convert, see how to convert Dolby Vision profile 7 to 8.1 without re-encoding.

Remux Doctor is coming soon for Macs with Apple silicon.