hdr-audit

What this skill does

# HDR Content Audit

Analyze HDR metadata and detect fake/invalid HDR content. HDR is not automatically better than SDR—many "HDR" releases are fake.

## What Makes HDR Real

Legitimate HDR requires:
1. **10-bit color depth** (minimum)
2. **HDR transfer function** (PQ or HLG)
3. **Actual extended brightness** (content above 100 nits)
4. **Mastered in HDR** from HDR source or graded for HDR

## Fake HDR Indicators

**Inverse tonemapped SDR**:
- SDR content artificially expanded to HDR range
- No actual detail gained in highlights
- Often looks flat or washed out on HDR displays
- Content never officially released in HDR

**HDR container, SDR content**:
- HDR metadata present but peak brightness never exceeds ~100 nits
- Tagged as HDR but visually identical to SDR

**Suspicious Dolby Vision**:
- Content only officially released in SDR
- DV metadata on old catalog titles
- Random releases that don't match official offerings

## MediaInfo HDR Fields

Key fields to check in Video section:

```
HDR format                   : SMPTE ST 2086 / SMPTE ST 2094...
Color primaries              : BT.2020
Transfer characteristics     : PQ (SMPTE 2084) or HLG
Matrix coefficients          : BT.2020 non-constant
Mastering display color prim : BT.2020 or DCI-P3
Mastering display luminance  : min: 0.0050 cd/m2, max: 1000 cd/m2
MaxCLL                       : 1000 cd/m2
MaxFALL                      : 400 cd/m2
```

## Audit Workflow

### Step 1: Check Basic HDR Presence

Run MediaInfo and look for:
- Transfer characteristics: Should be PQ or HLG (not BT.709)
- Bit depth: Should be 10 or 12 bit
- Color primaries: Should be BT.2020 (wide color gamut)

**If any are missing/wrong**: Not HDR, or broken HDR.

### Step 2: Check Mastering Metadata

Look for mastering display info:
- **MaxCLL** (Content Light Level): Peak brightness in content
- **MaxFALL** (Frame Average Light Level): Average peak per frame
- **Mastering display luminance**: Range used in grading

**Red flags**:
- MaxCLL ≤ 100 nits (SDR range only)
- No mastering metadata at all
- Generic/placeholder values

### Step 3: Verify Official HDR Release Exists

Research whether the content was officially released in HDR:
- Check streaming services (Netflix, Disney+, etc.)
- Check UHD Blu-ray releases
- Search for official announcements

**If no official HDR exists**: The "HDR" version is almost certainly fake.

### Step 4: Visual Inspection (If Possible)

On an HDR display:
- Does the content use the extended brightness range?
- Are highlights noticeably brighter than SDR?
- Does it look natural or artificially boosted?

## HDR Formats

### HDR10

- Static metadata (one set of values for whole video)
- Most common format
- Open standard

**MediaInfo shows**:
```
HDR format: SMPTE ST 2086
```

### HDR10+

- Dynamic metadata (per-scene or per-frame optimization)
- Samsung/Amazon developed
- Not widely supported

**MediaInfo shows**:
```
HDR format: SMPTE ST 2094 App 4
```

### Dolby Vision

- Dynamic metadata
- Profile-based system (various capabilities)
- Requires licensing

**MediaInfo shows**:
```
HDR format: Dolby Vision, dvhe.05.06
```

**Dolby Vision Profiles**:
- Profile 5: Single layer, common for streaming
- Profile 7: Dual layer with base HDR10
- Profile 8: Similar to Profile 5 with HLG base

## Quick Reference

| Check | Expected for Real HDR | Fake HDR Indicator |
|-------|----------------------|-------------------|
| MaxCLL | >100 nits | ≤100 nits |
| Transfer | PQ or HLG | BT.709 tagged as HDR |
| Bit depth | 10+ bit | 8 bit |
| Official release | Yes | No HDR release exists |
| Visual brightness | Extended range used | Looks like SDR |

## Common Fake HDR Scenarios

**Older movies "remastered" in HDR**:
- If studio didn't announce HDR remaster, it's fake
- Many pirate releases add fake HDR to old content

**Anime in HDR**:
- Very few anime are produced in HDR
- Most "HDR anime" is inverse tonemapped

**Random Dolby Vision releases**:
- DV requires licensing and official mastering
- Unauthorized DV releases are synthetic conversions

## Recommendations

**When to use HDR version**:
- Official HDR release from studio
- MaxCLL shows actual extended brightness
- Content mastered specifically for HDR

**When to use SDR version**:
- No official HDR release
- HDR shows fake indicators
- SDR version has better encoding quality
- HDR version has conversion artifacts

## Additional Resources

- **`${CLAUDE_PLUGIN_ROOT}/references/hdr.md`** - Detailed HDR metadata guide
- **`${CLAUDE_PLUGIN_ROOT}/references/color-space.md`** - Color space fundamentals