HDR Limit

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HDR Limit QC provides comprehensive High Dynamic Range content validation, ensuring your HDR material meets delivery specifications for various HDR formats and platforms.

Overview

The HDR Limit tool monitors:

  • Peak brightness levels (nits)

  • Average brightness (MaxFALL compliance)

  • Color volume boundaries

  • PQ/HLG encoding compliance

This is essential for:

  • HDR10 and HDR10+ mastering

  • Dolby Vision deliverables

  • HLG broadcast content

  • Streaming platform requirements

Enabling the Tool

  1. Open the QC panel (View > QC Panel or use the toolbar button)

  2. Enable HDR Limit checkbox

  3. Select your target HDR format

  4. Configure threshold settings

How It Works

HDR Limit performs per-frame analysis:

  1. Decodes PQ or HLG signal to linear light values

  2. Calculates peak luminance per frame

  3. Tracks running average for MaxFALL

  4. Compares against format-specific limits

  5. Logs violations to QC Timeline

Settings

Setting
Description
Default

HDR Format

Target HDR specification

HDR10

Max Peak (nits)

Maximum peak brightness allowed

1000

Max Average (nits)

Maximum frame average (MaxFALL)

400

Error Threshold

Pixel percentage to trigger error

0.1%

HDR Format Presets

Preset
Max Peak
Max Average
Notes

HDR10 (1000 nits)

1000

400

Standard HDR10

HDR10 (4000 nits)

4000

1000

Premium HDR10

Dolby Vision

4000

1000

Profile dependent

HLG

1000

400

Broadcast HDR

Custom

User-defined

User-defined

Manual settings

Reading the Results

In the QC Panel

Real-time display shows:

  • Current Peak: Maximum nits in current frame

  • Max Peak: Highest peak seen in session

  • Current Average: Frame average luminance

  • MaxFALL: Running content average

  • Status: Pass/Warning/Error indicator

In the Timeline

HDR limit violations appear as:

  • Yellow markers: Approaching limits (warning)

  • Red markers: Exceeding limits (error)

  • Hover for details including peak nits value

In Exports

QC reports include:

  • Timecode of each violation

  • Peak brightness value

  • Whether MaxCLL or MaxFALL was exceeded

  • Frame-by-frame statistics

Use Cases

HDR10 Mastering

Validate content for HDR10 delivery:

  1. Select HDR10 (1000 nits) preset

  2. Enable MaxFALL tracking

  3. Run full content playback

  4. Review any flagged frames

Streaming Platform QC

Different platforms have different requirements:

Platform
Typical Max Peak
Notes

Netflix

1000-4000 nits

Content dependent

Amazon

1000-4000 nits

HDR10/DV supported

Apple TV+

Up to 4000 nits

Dolby Vision preferred

YouTube

1000 nits

HDR10 support

Broadcast HDR (HLG)

For HLG broadcast delivery:

  1. Select HLG preset

  2. Set Max Peak to broadcaster requirement

  3. Enable average brightness monitoring

  4. Verify against delivery specs

Understanding HDR Metrics

MaxCLL (Maximum Content Light Level)

The brightest pixel in the entire content. HDR Limit tracks this continuously and reports the highest value encountered.

MaxFALL (Maximum Frame Average Light Level)

The highest frame average luminance in the content. This affects tone mapping on consumer displays.

Why Both Matter

  • Displays use MaxCLL/MaxFALL metadata for tone mapping

  • Incorrect values cause poor playback on consumer TVs

  • Some platforms require specific limits for acceptance

Standards Reference

Standard
MaxCLL
MaxFALL
Color Volume

HDR10

1000-10000

400-4000

Rec.2020/PQ

HDR10+

Dynamic

Dynamic

Rec.2020/PQ

Dolby Vision

4000+

1000+

Rec.2020/PQ

HLG

~1000

~400

Rec.2020/HLG

Tips

  • Always verify delivery specs with your distributor

  • Use HDR Statistics scope for detailed MaxCLL/MaxFALL measurement

  • Test problematic frames in the False Color scope with HDR preset

  • Consider headroom - staying below 90% of limits is good practice

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