HLG+ not reported when Dolby Vision Profile 8.4 is also present (ST 2094-40 oriented 0x0003)

[aberthil]

Summary

When Dolby Vision Profile 8.4 (dvvC, BL signal compatibility HLG) and SMPTE ST 2094-40 with T.35 oriented code 0x0003 (HLG+) are both present, MediaInfo labels the ST 2094 half as HDR10+ Profile A instead of HLG+.

The same ST 2094-40 SEI bitstream, remuxed without dvvC, is correctly labelled HLG+ compatible.

Related: #2536 (HLG+ support).

MediaInfo version

MediaInfo Command line
MediaInfoLib - v26.05

(Windows x64 CLI from MediaArea; also reproduced with the same lib in our bundled copy.)

Expected

HDR format : Dolby Vision, Version 1.0, Profile 8.4, ..., HLG compatible / SMPTE ST 2094 App 4, Version 1, HLG+ compatible
Transfer characteristics : HLG

HDR_Format_Compatibility should be something like: HLG / HLG+

Actual

HDR format : Dolby Vision, Version 1.0, Profile 8.4, dvhe.08.07, BL+RPU, no metadata compression, HLG compatible / SMPTE ST 2094 App 4, Version HDR10+ Profile A, HDR10+ Profile A compatible
Transfer characteristics : HLG
Codec configuration box : hvcC+dvvC

Inform fields:

Field	Value
HDR_Format	Dolby Vision / SMPTE ST 2094 App 4
HDR_Format_Compatibility	HLG / HDR10+ Profile A
HDR_Format_Version	1.0 / 1
transfer_characteristics	HLG
colour_primaries	BT.2020
BitDepth	10

Control (same SEI, no dvvC)

Remux the HEVC access units to a plain hvc1 MP4 (no Dolby Vision configuration box). MediaInfo then reports:

HDR format : SMPTE ST 2094 App 4, Version 1, HLG+ compatible
Transfer characteristics : HLG
Codec configuration box : hvcC

Field	Value
HDR_Format	SMPTE ST 2094 App 4
HDR_Format_Compatibility	HLG+
HDR_Format_Version	1

So the ST 2094-40 payload is accepted as Profile A and the HLG→HLG+ rewrite works when Dolby Vision is absent.

Bitstream proof (T.35 header)

Prefix SEI, user_data_registered_itu_t_t35, first bytes of payload:

B5 00 3C 00 03 04 01 ...
│  │     │     │  └ application_version = 1
│  │     │     └ application_identifier = 4 (ST 2094 App 4)
│  │     └ oriented_code = 0x0003  ← HLG / ST 2094-40 (not 0x0001 PQ HDR10+)
│  └ provider_code = 0x003C
└ country_code = 0xB5

Present on every sampled frame. No 0x0001 T.35 App 4 messages in the file.

Per HDR10+/HLG+ docs:

• 0x0001 → ST 2094-40 when transfer is PQ
• 0x0003 → ST 2094-40 when transfer is HLG (HLG+)

Likely cause

In File__Analyze_Streams_Finish.cpp the HLG+ rewrite only runs when the entire compatibility string starts with "HDR10":

if (Retrieve(..., Video_HDR_Format_Compatibility).rfind(__T("HDR10"), 0)==0
 && ( ... || transfer != PQ || ... ))
{
    if (transfer == HLG && Compatibility.rfind("HDR10+ Profile A", 0)==0)
        Fill(..., "HLG+");
    else
        Clear(...);
}

With Dolby Vision 8.4 first, compatibility is HLG / HDR10+ Profile A, which does not start with HDR10, so the ST 2094 half is never rewritten to HLG+.

Suggested fix: apply the HDR10+ Profile A → HLG+ rewrite per /-separated HDR format slot (when that slot is ST 2094 App 4 / Profile A and transfer_characteristics is HLG), instead of only when the concatenated string begins with HDR10.

Secondary display quirk: the human-readable line shows Version HDR10+ Profile A for the ST 2094 half even though HDR_Format_Version is 1.0 / 1.

How the sample was produced

1. Source: iPhone HEVC Main 10, Dolby Vision Profile 8.4, transfer HLG (arib-std-b67).
2. Measure HLG pictures → HDR10+ Profile A JSON (scene MaxScl / distributions).
3. Inject ST 2094-40 SEI with oriented code 0x0003 into the existing bitstream without stripping NAL 62 / dvvC.

Samples

Attached / linked:

1. dv84_hlgplus_short.mov — DV 8.4 + HLG+ SEI (hvcC+dvvC) → MediaInfo shows HDR10+ Profile A for ST 2094.
2. same_sei_no_dvvc.mp4 — same SEI access units, no dvvC → MediaInfo shows HLG+.

Happy to re-upload or trim further if needed.

[JeromeMartinez]

Happy to re-upload or trim further if needed.

Looks like I lost them (shame on me, I use to keep all files for regression tests), please re-upload.

[aberthil]

Re-uploaded repro samples:

https://github.com/aberthil/Dolby-Vision-Scripts/releases/download/mediainfo-hlgplus-dv84-repro/mediainfo_hlgplus_dv84_repro.zip

Zip contains:

• dv84_hlgplus_short.mov — DV 8.4 + HLG+ SEI (hvcC+dvvC)
• same_sei_no_dvvc.mp4 — same SEI, no dvvC (control)
• mediainfo-hlgplus-dv84-issue.md — write-up

[aberthil]

Public download (earlier link was on a private monorepo — sorry):

https://github.com/aberthil/mediainfo-hlgplus-dv84-repro/releases/download/v1/mediainfo_hlgplus_dv84_repro.zip

Zip: dv84_hlgplus_short.mov (DV 8.4 + HLG+), same_sei_no_dvvc.mp4 (control, no dvvC), plus write-up markdown.