SDR → HDR

SDR 到 HDR 的色彩科学演变The Color Science Evolution from SDR to HDR

1. 亮度动态范围：HDR 把"能显示多亮"提高了 10–100 倍1. Luminance dynamic range: HDR raises the display ceiling by 10–100×

SDR 电视的峰值亮度上限是 100 nit；超过这个值，颜色就被压成白色。HDR 把上限推到 1,000–10,000 nit，让高亮区域在更亮的同时还能保持颜色饱和度。两者的核心差距不在于"整体更亮"，而在于 高光区域能否同时"亮"与"有色"。An SDR reference display peaks at 100 nits; values beyond that range must be compressed and may lose color as they approach white. HDR extends the ceiling toward 1,000–10,000 nits so highlights can become brighter while retaining saturation. The essential difference is not that the entire image is brighter, but whether highlights can remain both bright and colorful.

拖动下方滑块改变 HDR 峰值，上方四个数字会同步更新。图表横轴为对数刻度——这反映了人眼对亮度的感知方式：暗部差异比亮部差异更敏感。Move the slider below to change the HDR peak; the four values above update with it. The chart uses a logarithmic axis, reflecting the eye's greater sensitivity to luminance differences in dark regions than in bright ones.

SDR 峰值白SDR peak white 100 nit BT.709 / BT.1886 标准上限BT.709 / BT.1886 reference ceiling

HDR 参考白（图形安全白）HDR reference white (graphics white) 203 nit BT.2408 规定，约为 SDR 参考白的 2 倍BT.2408 value, about 2× SDR reference white

当前 HDR 峰值Current HDR peak 1,000 nit 由滑块控制Controlled by the slider

相对 SDR 峰值倍数Multiple of SDR peak 10× 高光余量扩展幅度Highlight-range expansion

HDR 峰值亮度HDR peak luminance 1,000 nit

SDR 可用范围（到 100 nit）SDR range (to 100 nits) HDR 高光余量（100 nit → 峰值）HDR highlight range (100 nits → peak) 203 nit HDR 参考白203-nit HDR reference white

当前 HDR 峰值：1,000 nit；比 SDR 高出 10×

SDR

标准动态范围 · BT.709Standard Dynamic Range · BT.709

峰值白：100 nit（硬上限）Peak white: 100 nits (hard limit)
编码标准：BT.709 OETF + BT.1886 EOTFEncoding: BT.709 OETF + BT.1886 EOTF
高光处理：超过 100 nit → 颜色压白，饱和度丢失Highlights: above 100 nits → compressed toward white, losing saturation
编码位深：8 bit，256 个亮度级别Bit depth: 8-bit, 256 code levels
颜色空间：BT.709（约覆盖 36% CIE 色域）Color space: BT.709 (about 36% of the CIE diagram)

HDR

高动态范围 · BT.2100High Dynamic Range · BT.2100

峰值白：1,000–10,000 nit（可变）Peak white: 1,000–10,000 nits (variable)
编码标准：PQ (ST 2084) 或 HLG (BT.2100)Encoding: PQ (ST 2084) or HLG (BT.2100)
高光处理：203 nit 以上仍保持颜色饱和度Highlights: retain color saturation above 203 nits
编码位深：10/12 bit，1,024–4,096 个亮度级别Bit depth: 10/12-bit, 1,024–4,096 levels
颜色空间：BT.2020（约覆盖 76% CIE 色域）Color space: BT.2020 (about 76% of the CIE diagram)

高亮颜色对比：SDR 通道剪切 vs HDR 保持饱和（真实 HDR 图片）Bright-color comparison: SDR channel clipping vs HDR saturation retention (true HDR image)

每一行是同一颜色的"亮度阶梯"，从左到右 1 nit → 1,000 nit。左半屏模拟 SDR（每个 RGB 通道在 100 nit 处硬剪切，导致橙色→黄色等色相偏移）；右半屏是真实 HDR 渲染。Each row is a luminance ramp of one color from 1 nit to 1,000 nits. The left half simulates SDR by hard-clipping each RGB channel at 100 nits, causing hue shifts such as orange toward yellow; the right half is rendered as true HDR.

SDR · 100 nit 剪切SDR · clipped at 100 nit

HDR · 1,000 nit PQ

※ 图片为 AVIF · BT.2020 · SMPTE ST 2084 (PQ) · 10-bit · MaxCLL 1,000 nit。在支持 EDR 的 macOS 显示器（XDR / Pro Display XDR / mini-LED MacBook Pro / iPhone Pro）+ Safari 17 或 Chrome 116+ 上自动渲染为真 HDR；其他环境降级为 SDR JPEG（仍能看到色相偏移差异，但右半屏不会真的"更亮"）。※ The image is AVIF · BT.2020 · SMPTE ST 2084 (PQ) · 10-bit · MaxCLL 1,000 nit. On EDR-capable macOS displays (XDR / Pro Display XDR / mini-LED MacBook Pro / iPhone Pro) with Safari 17 or Chrome 116+ it renders as true HDR; elsewhere it falls back to an SDR JPEG (you can still see the hue-shift difference, but the right half won't actually be "brighter").

2. Gamma：从 CRT 缺陷到主动利用视觉2. Gamma: from a CRT limitation to perceptual coding

PDF 中强调了一个关键转变：早期伽玛像是在“校正 CRT 非线性”，但到了现代显示与数字编码，伽玛更像是在主动压缩动态范围、提高量化资源利用率。下面把 OETF、EOTF、OOTF 分开看，避免把拍摄编码、显示解码和系统观感混在一起。The PDF emphasizes an important shift: gamma began as a way to compensate for CRT nonlinearity, but in modern displays and digital coding it actively compresses dynamic range and allocates quantization more efficiently. Separating OETF, EOTF, and OOTF prevents camera encoding, display decoding, and overall system rendering from being conflated.

信号链关系Signal-chain relationship

OETF场景光 → 信号Scene light → signal

→

EOTF信号 → 显示光Signal → display light

OOTF场景 → 屏幕Scene → screen

组合关系：Composition: OOTF = EOTF ∘ OETF

SDR 近似：SDR approximation: γ_OOTF ≈ γ_OETF × γ_EOTF = 0.5 × 2.4 ≈ 1.2

这里的乘法指幂函数指数相乘，不是把亮度值直接相乘。This multiplication combines power-function exponents; it does not multiply luminance values directly.

显示端天生非线性The display is inherently nonlinear

显像管 EOTF 近似 V^2.2，摄像机端用约 L^0.45 预失真抵消。A CRT's EOTF is approximately V^2.2; the camera applies about L^0.45 to compensate.

低反差记录，高反差放映Low-contrast capture, high-contrast projection

底片低伽玛压缩动态范围，发行拷贝高伽玛扩展反差，本质也是感知编码。Low-gamma negative film compresses dynamic range, while high-gamma release prints expand contrast: another form of perceptual encoding.

BT.709 OETF

暗部线性段 + 0.45 幂函数段，实际近似 0.5，成为 SDR 拍摄制作基础。A linear toe plus a 0.45 power segment, often approximated as 0.5, became a foundation of SDR capture and production.

BT.1886 EOTF

把平板、OLED、投影等“非 CRT”显示规范到接近 2.4 的显示伽玛。Standardized flat panels, OLEDs, and projectors around a display gamma near 2.4.

BT.2100 HDR

PQ 与 HLG 进入同一 HDR-TV 标准框架，2025 版 BT.2100-3 继续更新图像参数建议。PQ and HLG entered one HDR-TV framework, with BT.2100-3 updating image-parameter guidance in 2025.

① 转换函数① Transfer function

先选信号链中的哪一段First pick which stage of the chain

② 曲线选择② Curve selection

把要比较的曲线拉进同一张图Bring the curves you want to compare onto one chart

③ 显示参数③ Display parameters

HLG 峰值 1000 nit

移动指针读取标准曲线数值Move the pointer to read the curve values

OETF：拍摄/编码端OETF: capture / encoding

OETF 把场景相对亮度变成视频信号。BT.709 是 SDR 摄像机伽玛；HLG 的 OETF 是 BT.2100 定义的 HDR 广播编码曲线。PQ 是显示亮度到码值的绝对亮度编码，可在上方切到“PQ 编码”单独查看。OETF converts relative scene light into a video signal. BT.709 is an SDR camera curve; the HLG OETF is the HDR broadcast encoding curve defined by BT.2100. PQ encodes absolute display luminance into code values and can be viewed separately using the PQ encoding option above.

场景光Scene light
Scene light

→

信号Signal
OETF 编码OETF encode

→

显示光Display light
EOTF 解码EOTF decode

当前只看编码端：Y 轴是归一化视频信号，不是 nit。BT.709 与 HLG 是真正的场景 OETF；PQ 曲线是按 L×参考峰值换算后的编码参考，可在 ② 中取消其他曲线单独查看。

3. PQ 与 HLG：HDR 的两条路线3. PQ and HLG: two routes to HDR

PQ（ST 2084）把码值映射到绝对显示亮度，面向精准母版、元数据与显示适配；HLG 把传统广播链路放在首位，信号相对、兼容 SDR 观看，但依赖终端根据峰值亮度设置系统伽玛。PQ (ST 2084) maps code values to absolute display luminance for precise mastering, metadata, and display adaptation. HLG prioritizes the traditional broadcast chain: its signal is relative and more compatible with SDR viewing, but the receiver sets system gamma according to display peak luminance.

在曲线上移动鼠标或触控，查看同一归一化信号在 PQ、HLG、SDR gamma 下对应的近似亮度。切换对数坐标会更容易看清暗部码值分配。Move a pointer across the curves to compare the approximate luminance represented by the same normalized signal in PQ, HLG, and SDR gamma. Log scale makes shadow-code allocation easier to see.

HLG 显示峰值HLG display peak 1000 nit

移动指针读取曲线Move the pointer to read the curves

PQ — 绝对亮度体系PQ — absolute luminance

Display Referred EOTF

ST 2084 / PQ 的设计上限为 10,000 cd/m²。码值直接对应绝对显示亮度（与终端无关），因此同一信号在不同显示器上试图呈现相同的 nit 值。适合精确调色母版、电影与流媒体。
⚠ 低亮度显示器无法还原母版中超出自身峰值的部分，需要 Tone Mapping 或元数据辅助。ST 2084 / PQ has a design ceiling of 10,000 cd/m². Code values correspond to absolute display luminance, so the same signal aims at the same nit value on different displays. This suits precise grading, cinema, and streaming masters.
⚠ A lower-peak display cannot reproduce portions of a master above its capability and therefore requires tone mapping or metadata assistance.

1. 先把码值 V 做感知反压缩1. Perceptually de-compress code value V

N = V^1/m₂

2. 计算归一化亮度比例2. Compute the normalized luminance ratio

Y = ( max(N − c₁, 0) / (c₂ − c₃·N) )^1/m₁

3. 转成绝对显示亮度3. Convert to absolute display luminance

L = 10000 × Y cd/m²

常量：Constants: m₁=2610/16384 · m₂=2523/32 · c₁=107/128 · c₂=2413/128 · c₃=2392/128

HLG — 相对亮度体系HLG — relative luminance

Scene Referred OETF

HLG 定义的是拍摄端 OETF，码值表示相对场景亮度，与终端显示峰值无直接绑定。EOTF 随终端峰值自动调整系统伽玛（BT.2100：γ = 1.2 + 0.42·log₁₀(Lw/1000)），可在不同峰值显示器上自适应。不强制动态元数据，对广播链路友好。HLG defines a camera-side OETF. Its code values represent relative scene light and are not directly tied to display peak. The display system adjusts gamma according to peak luminance (BT.2100: γ = 1.2 + 0.42·log₁₀(Lw/1000)), adapting across displays without requiring dynamic metadata and fitting broadcast workflows.

1. 低亮段：保留暗部细节1. Low end: preserve shadow detail

E′ = √(3E), 0 ≤ E ≤ 1/12

2. 高亮段：用对数压缩高光2. High end: log-compress the highlights

E′ = a·ln(12E − b) + c, E > 1/12

3. 两段交界3. The junction

E = 1/12 时，E′ = 0.5，曲线连续at E = 1/12, E′ = 0.5, and the curve is continuous

常量：Constants: a=0.17883277 · b=0.28466892 · c=0.55991073

PQ流程PQ workflow

通知模式（Notify）Notify model

ST 2084 只定义 PQ EOTF 及其反函数，本身不要求携带静态元数据。在 HDR10 等具体交付配置中，通常还会传递 ST 2086 母版显示信息，以及 CTA-861.3 定义的 MaxCLL、MaxFALL；HDR10+、Dolby Vision 等动态格式还可逐场景或逐镜头给出映射信息，辅助显示端自适应 Tone Mapping。ST 2084 defines only the PQ EOTF and its inverse; it does not itself require static metadata. Specific delivery profiles such as HDR10 commonly add ST 2086 mastering-display information and MaxCLL/MaxFALL as defined by CTA-861.3. Dynamic formats such as HDR10+ and Dolby Vision may also supply mapping information per scene or shot to assist adaptive tone mapping.

HLG流程HLG workflow

约定模式Convention-based mode

HLG 制播更像 SDR：前端与终端按约定解释信号。终端峰值越高，系统伽玛随之增大（BT.2100：γ = 1.2 + 0.42·log₁₀(Lw/1000)），自动压低平均亮度，保持中间调观感稳定。HLG production resembles SDR: source and receiver interpret the signal by convention. System gamma increases with display peak (BT.2100: γ = 1.2 + 0.42·log₁₀(Lw/1000)), lowering average luminance to keep midtone appearance stable.

HDR 参考白：203 nit（BT.2408 规定）HDR reference white: 203 nits (BT.2408)

参考白不是 HDR 的“最亮白”，而是普通漫反射白、字幕/图形白、SDR 内容嵌入 HDR 工作流时的亮度锚点。PQ 和 HLG 共用同一参考白亮度 203 cd/m²，但对应的信号电平不同：Reference white is not HDR's brightest white. It is the luminance anchor for ordinary diffuse white, subtitles and graphics, and SDR content embedded in an HDR workflow. PQ and HLG use the same 203 cd/m² reference-white luminance but represent it at different signal levels.

PQ：58% 电平 = 203 nitPQ: 58% level = 203 nits

100% PQ 对应 10,000 nit；在 1000 nit 监视器上，58% 是 HDR 制作参考白基准，51% 对应 100 nit（SDR 参考白）。100% PQ corresponds to 10,000 nits; on a 1000-nit monitor, 58% is the HDR reference-white baseline and 51% corresponds to 100 nits (SDR reference white).

HLG：75% 电平 = 203 nit（HLG75）HLG: 75% level = 203 nits (HLG75)

HLG 参考白基准定在 75%（BT.2390 / BT.2408），早期曾用 50%（HLG50，已废弃）。波形监视器上的"1000 nit"刻度即指 75% HLG 电平。The HLG reference-white baseline is set at 75% (BT.2390 / BT.2408); an earlier 50% (HLG50) is now deprecated. The "1000 nit" mark on a waveform monitor refers to the 75% HLG level.

Headroom：参考白以上才是 HDR 的“高光余量”Headroom: HDR highlight capacity begins above reference white

如果把 203 nit 当作普通白，那么显示器峰值亮度中超过 203 nit 的部分就是 headroom。它不是拿来把整张画面都变亮，而是留给太阳反光、金属高光、火焰、霓虹、雪地闪光等短暂或局部的亮度。With 203 nits as ordinary white, the display capacity above 203 nits is headroom. It is not intended to brighten the whole picture, but to carry brief or local highlights such as sunlight reflections, metallic glints, flames, neon, and sparkling snow.

600 nit

约 3× headroom
高光余量有限~3× headroom
limited highlight range

1000 nit

约 4.9× headroom
常见 HDR 母版目标~4.9× headroom
common HDR master target

2000 nit

约 9.9× headroom
高光层次更宽~9.9× headroom
wider highlight gradation

4000 nit

约 19.7× headroom
接近高峰值创作空间~19.7× headroom
near high-peak creative range

PQ 母版分级（BT.2408 操作实践）PQ mastering levels (BT.2408 operational practice)

PQ 是绝对亮度体系，100% 电平固定对应 10,000 nit，参考白 203 nit 固定对应 58% 电平。
不同峰值监视器上制作的母版，其信号电平上限不同：PQ is an absolute-luminance system: 100% corresponds to 10,000 nits and 203-nit reference white corresponds to about 58%. Masters made on displays with different peaks therefore use different maximum signal levels.

PQ600

600 nit 监视器
最高电平 ≈ 70%600-nit monitor
max level ≈ 70%

PQ1000

1000 nit 监视器
最高电平 ≈ 75%1000-nit monitor
max level ≈ 75%

PQ2000

2000 nit 监视器
最高电平 ≈ 83%2000-nit monitor
max level ≈ 83%

PQ4000

4000 nit 监视器
最高电平 ≈ 90%4000-nit monitor
max level ≈ 90%

4. 色彩空间：从 BT.709 到 BT.20204. Color spaces: from BT.709 to BT.2020

HDR 通常伴随更宽色域。BT.709 是 HDTV/SDR 的常用工作空间；DCI-P3 来自数字电影；BT.2020 是 UHD/HDR 传输容器，覆盖更大范围，但现实显示器常只能覆盖其中一部分。HDR is commonly paired with a wider gamut. BT.709 is the standard working space for HDTV and SDR; DCI-P3 comes from digital cinema; and BT.2020 is the broader UHD/HDR delivery container, although real displays usually reproduce only part of it.

点击右侧色域卡片，SVG 色度图会突出对应三角形。覆盖率为 CIE 1931 xy 色度图近似面积占比：BT.709 约 35.9%，P3 约 53.6%，BT.2020 约 75.8%。Select a gamut card to highlight its triangle on the SVG chromaticity diagram. Coverage is the approximate share of the CIE 1931 xy diagram: about 35.9% for BT.709, 53.6% for P3, and 75.8% for BT.2020.

BT.709 / sRGB

R 0.640,0.330 · G 0.300,0.600 · B 0.150,0.060

典型覆盖：35.9%Typical coverage: 35.9%

DCI-P3 / Display P3

R 0.680,0.320 · G 0.265,0.690 · B 0.150,0.060

典型覆盖：53.6%Typical coverage: 53.6%

BT.2020

R 0.708,0.292 · G 0.170,0.797 · B 0.131,0.046

典型覆盖：75.8%Typical coverage: 75.8%

在色度图上移动鼠标可读取 xy 坐标Move across the diagram to read xy coordinates

ICtCp

BT.2100 推荐的 HDR / WCG 色差编码BT.2100's recommended color-difference encoding for HDR/WCG

传统 Y'CbCr 在 HDR 和宽色域下会产生明显的色调旋转误差（hue rotation error）——高饱和色在量化后色相偏移。ICtCp 基于 PQ 或 HLG 的感知均匀色差空间，使色差分量对高亮高饱和颜色更线性。Traditional Y'CbCr can produce visible hue-rotation errors with HDR and wide-gamut signals, shifting highly saturated colors after quantization. ICtCp is a more perceptually uniform color-difference space based on PQ or HLG, making its chroma components more linear for bright, saturated colors.

I（Intensity）承载亮度；Ct 为蓝-黄方向色差（tritan 轴）；Cp 为红-绿方向色差（protan 轴），对应人眼最敏感的两条色差轴。I (Intensity) carries luminance; Ct is the blue-yellow color-difference direction (tritan axis); and Cp is the red-green direction (protan axis), corresponding to two important axes of human color discrimination.

特性Property	Y'CbCr	ICtCp
色调旋转误差Hue-rotation error	明显Visible	极小Minimal
感知均匀性Perceptual uniformity	低Low	高High
适用范围Scope	SDR / BT.709	HDR / WCG
传递函数基础Transfer-function basis	Gamma	PQ 或 HLGPQ or HLG
典型用途Typical use	广播、编码存储Broadcast and coding	后期、质量评估Post-production and quality assessment

5. 色彩体积：色域 × 亮度，不只是三角形变大5. Color volume: gamut × luminance, not just a larger triangle

色彩空间只描述 xy 平面上的色度范围；色彩体积把亮度轴也加进来。HDR 的价值在于：高亮区域仍能保留颜色，而不是像 SDR 那样接近白色剪切。A color space describes chromaticity on the xy plane; color volume adds the luminance axis. HDR's value is that bright regions can retain color instead of approaching white clipping as they do in SDR.

调节峰值亮度和色域，观察“可表达颜色的三维空间”如何增大。实际显示还受面板峰值、ABL、色彩管理和色调映射影响。Adjust peak luminance and gamut to see how the three-dimensional space of reproducible colors grows. Real displays are also constrained by panel peak, ABL, color management, and tone mapping.

xyY 几何体积：18.9× SDR基准

峰值亮度Peak luminance 1000 nit 色域底面Gamut base BT.2020 xy area 0.2119

SDR

BT.709 色域 × 100 nit。高亮颜色容易向白色压缩，色彩体积有限。BT.709 gamut × 100 nits. Bright colors are readily compressed toward white, limiting color volume.

HDR

BT.2020 容器 × 更高亮度。霓虹、火焰、金属反光等可以同时“亮且有色”。BT.2020 container × higher luminance. Neon, flames, and metallic reflections can remain both bright and colorful.

计算口径：V_xyY = A_xy × L_peak；A_xy = 1/2 |Σ(x_iy_i+1 − x_i+1y_i)|。

6. HDR 格式与对比：元数据决定“如何适配显示器”6. HDR formats: metadata determines how content adapts to a display

HDR10、HDR10+、Dolby Vision、HLG、HDR Vivid、Eclipsa Video 都可承载 HDR，但它们对 EOTF、元数据、授权、兼容性和场景适配的选择不同。HDR10, HDR10+, Dolby Vision, HLG, HDR Vivid, and Eclipsa Video can all carry HDR, but make different choices about transfer functions, metadata, licensing, compatibility, and display adaptation.

先切换标签理解每种格式，再用下方表格横向比较。核心判断不是“谁更亮”，而是谁能把创作者意图更稳定地映射到不同峰值、黑位和色域的终端上。Use the tabs to understand each format, then compare them in the table below. The central question is not which is brighter, but which can map creative intent more consistently across displays with different peaks, black levels, and gamuts.

HDR10：PQ + BT.2020 + 静态元数据HDR10: PQ + BT.2020 + static metadata

HDR10 是最基础、最广泛的 HDR 媒体配置。它使用 ST 2084 / PQ EOTF、10 bit、BT.2020 容器，以及 ST 2086 母版显示信息和 CTA-861.3 定义的 MaxCLL、MaxFALL。弱点是静态元数据只给整部内容一个全局描述，显示适配较粗。HDR10 is the most basic and widely supported HDR media profile. It uses the ST 2084 PQ EOTF, 10-bit encoding, a BT.2020 container, ST 2086 mastering-display information, and MaxCLL/MaxFALL as defined by CTA-861.3. Its limitation is that static metadata describes the entire program globally, allowing only coarse display adaptation.

EOTFPQ / ST 2084

元数据Metadata静态Static

位深Bit depth10 bit

适合Best forUHD Blu-ray、流媒体基础层UHD Blu-ray, streaming base layer

HDR10+：在 HDR10 上加入动态元数据HDR10+: dynamic metadata added to HDR10

HDR10+ 使用 ST 2094-40 动态元数据，可逐场景或逐帧给出显示映射信息。2025 年 HDR10+ Technologies 推出 HDR10+ Advanced，强调更精细的亮度映射、环境适配和游戏等扩展体验。HDR10+ uses ST 2094-40 dynamic metadata to provide display-mapping information per scene or frame. HDR10+ Advanced, introduced by HDR10+ Technologies in 2025, emphasizes finer luminance mapping, ambient adaptation, gaming, and other extended experiences.

EOTFPQ / ST 2084

元数据Metadata动态 ST 2094-40Dynamic ST 2094-40

授权License相对开放的认证生态Relatively open certification ecosystem

适合Best for流媒体、电视、移动端Streaming, TV, mobile

Dolby Vision：动态元数据与端到端显示映射Dolby Vision: dynamic metadata and end-to-end display mapping

Dolby Vision 以逐场景/逐帧动态元数据和 Dolby 专有的显示映射链路为核心。元数据分层（L1 自动动态亮度、L2/L8 手动 Trim、L6 可选 MaxCLL/MaxFALL），允许调色师精确控制不同终端能力下的再现效果。常见发行链路多为 PQ / ST 2084，但 Dolby Vision 也有 HLG 兼容配置：Profile 8.4 使用 HLG base layer、BT.2020、HEVC Main10，并叠加 Dolby Vision RPU 元数据，非 Dolby Vision 设备可按 HLG 基础层显示。Dolby Vision centers on per-scene or per-frame dynamic metadata and Dolby's proprietary display-mapping chain. Its metadata levels include automated dynamic luminance in L1, manual trims in L2/L8, and optional MaxCLL/MaxFALL in L6, allowing colorists to control reproduction across different display capabilities. Most delivery paths use PQ/ST 2084, but Profile 8.4 uses an HLG base layer with BT.2020 and HEVC Main10 plus Dolby Vision RPU metadata, allowing non-Dolby devices to display the HLG base layer.

传递函数TransferPQ / ST 2084；Profile 8.4 可为 HLG base layerPQ / ST 2084; Profile 8.4 can use an HLG base layer

元数据MetadataDolby Vision 私有 RPU；不同于 ST 2094-10 Application #1Proprietary Dolby Vision RPU; distinct from ST 2094-10 Application #1

位深Bit depth最高 12 bit 工作流Up to a 12-bit workflow

授权License专有认证生态（厂商付费）Proprietary certification (paid by vendors)

Dolby Vision 2（2025 年 9 月发布）新特性：Dolby Vision 2 features (announced September 2025):

Precision Black：精细黑位控制，改善极暗场景表现；: refined black-level control for very dark scenes.
Light Sense：结合环境光传感器动态调整内容映射，适应不同观影环境；: adapts content mapping with ambient-light sensing.
Authentic Motion：运动场景与游戏内容的高帧率优化；: motion handling and high-frame-rate optimization.
Content Intelligence：内容智能分析，自动优化场景分类与映射策略。: content analysis for scene classification and mapping.

HLG：广播优先的相对 HDRHLG: broadcast-oriented relative HDR

HLG 由 BBC 与 NHK 推动，进入 BT.2100。它不依赖 HDR10 式元数据；非 HDR 终端可把 HLG 当作类似 SDR 的信号显示，通常不会完全崩坏，适合直播和电视播出。Developed by the BBC and NHK and standardized in BT.2100, HLG does not depend on HDR10-style metadata. A non-HDR display can treat the signal in an SDR-like way without catastrophic failure, making it well suited to live and broadcast television.

传递函数TransferHLG OETF/OOTF

元数据Metadata可无Optional / none

兼容性Compatibility较适合广播 SDR 共存Coexists well with broadcast SDR

适合Best for直播、体育、新闻、电视台Live, sports, news, broadcast

HDR Vivid：中国超高清产业的动态元数据 HDR 方案HDR Vivid: China's dynamic-metadata HDR system

HDR Vivid 由中国超高清视频产业联盟（CUVA）制定，标准编号 CUVA 005-2021，并于 2021 年 3 月正式发布。它同时支持 PQ 和 HLG 两种传递函数，通过动态元数据实现场景级亮度映射、SDR 下转兼容及多终端自适应显示。HDR Vivid was developed by the China Ultra HD Video Industry Alliance (CUVA) as CUVA 005-2021 and released in March 2021. It supports both PQ and HLG, using dynamic metadata for scene-level luminance mapping, SDR down-conversion compatibility, and adaptation across display types.

EOTFPQ 或 HLG（双模式）PQ or HLG (dual mode)

元数据Metadata动态：CUVA 005-2021Dynamic: CUVA 005-2021

位深Bit depth常见 10 bitCommonly 10-bit

标准机构Standards bodyCUVA（中国超高清视频产业联盟）CUVA (China Ultra HD Video Industry Alliance)

动态元数据功能：逐场景提供亮度范围、色域范围与映射参数；支持 SDR 回退——非 HDR 终端可通过内嵌 SDR 层正常播放；支持显示设备能力自适应，不同峰值与色域终端均可获得优化映射。Dynamic-metadata functions: per-scene luminance range, gamut range, and mapping parameters; SDR fallback through an embedded SDR layer; and adaptation to displays with different peaks and gamuts.

产业链覆盖：Industry coverage:

内容制作：央视、爱奇艺、优酷、腾讯视频等Content: CCTV, iQIYI, Youku, Tencent Video, and others
传输分发：IPTV、互联网 OTT 平台、有线/卫星Distribution: IPTV, OTT, cable, and satellite
终端设备：国产主流电视品牌（海信、TCL、创维等）Devices: major Chinese TV brands including Hisense, TCL, and Skyworth
4K/8K 超高清频道：4K 超高清频道（CCTV 4K）UHD channels: including CCTV 4K

Eclipsa Video：围绕参考白和 Headroom 的开放动态元数据Eclipsa Video: open dynamic metadata built around reference white and headroom

Eclipsa Video 采用 SMPTE ST 2094-50 公开委员会草案（Application #5）所描述的动态元数据方案，由 Google、Apple、NBCUniversal 等推动，并由 HDR10+ Technologies 启动相关项目。该文档目前不应称为已发布的现行 SMPTE 标准。它不是简单追求更高峰值亮度，而是把“标准内容的参考白”和“参考白以上的 HDR headroom”显式写进适配逻辑，让同一屏幕上的 SDR、网页 UI 与 HDR 视频更稳定地共存。Eclipsa Video uses the dynamic-metadata approach described by the SMPTE ST 2094-50 public committee draft (Application #5). It is promoted by Google, Apple, NBCUniversal, and others, with the related program launched by HDR10+ Technologies. The document should not currently be described as a published, active SMPTE standard. Rather than simply pursuing a higher peak, it explicitly incorporates standard-content reference white and HDR headroom above that anchor, helping SDR, web UI, and HDR video coexist more consistently on one display.

Reference White Anchor

先固定“普通白”的锚点First anchor ordinary white

显示器先知道标准内容、网页背景或普通白应该落在哪个亮度基准上；参考白以上的亮度能力，才留给 HDR 高光。这样 HDR 视频插在网页或系统界面里时，不会把周围 SDR 内容一起拉亮或压暗。The display first knows where standard content, a web background, or ordinary white should sit. Luminance capacity above reference white is then reserved for HDR highlights, preventing embedded HDR video from lifting or dimming surrounding SDR content.

Headroom-Adaptive Gain Curves

再按设备余量改映射曲线Then adapt the curve to device headroom

创作者可以给视频附带适配曲线。显示端如果 headroom 不足，就按曲线压缩阴影和中间调、保留高光层次；如果屏幕余量更大，就能更接近创作者指定的 HDR 外观。Creators can attach adaptation curves to the video. A display with limited headroom can use them to compress shadows and midtones while preserving highlight structure; a display with more headroom can approach the intended HDR appearance more closely.

文档基础Document basisSMPTE ST 2094-50 公开委员会草案 · Application #5SMPTE ST 2094-50 public committee draft · Application #5

核心元数据Core metadataReference White Anchor + Headroom-Adaptive Gain Curves

目标场景Target浏览器、手机、笔记本、混合 SDR/HDR 界面Browsers, phones, laptops, mixed SDR/HDR UIs

生态Ecosystem开放 HDR 视频项目，HDR10+ Technologies 负责项目推进Open HDR video program, driven by HDR10+ Technologies

综合对比表Format comparison

搜索或点击表头排序，快速比较格式差异。Search or sort by a table heading to compare formats quickly.

MaxCLL 与 MaxFALL：静态元数据的核心参数MaxCLL and MaxFALL: core static-metadata parameters

MaxCLL（Maximum Content Light Level）：整段内容中单个像素出现的最高亮度，单位 cd/m²。显示端用它判断高光峰值，决定映射曲线的上限锚点。MaxCLL (Maximum Content Light Level) is the highest luminance reached by an individual pixel anywhere in the program, in cd/m². A display can use it as an upper anchor when mapping highlights.

MaxFALL（Maximum Frame-Average Light Level）：整段内容中帧平均亮度的最高值，是显示端可参考的内容亮度描述，可辅助判断全屏亮度负载与映射策略。面板保护、热管理和 ABL 如何动作属于终端自身策略，并非由 MaxFALL 直接控制。MaxFALL (Maximum Frame-Average Light Level) is the highest frame-average luminance in the program. It describes content luminance that a display may consult when assessing full-screen load and mapping strategy. Panel protection, thermal management, and ABL behavior remain display policies and are not directly controlled by MaxFALL.

典型值：影院母版 MaxCLL ≈ 1000–4000 nit，MaxFALL ≈ 100–400 nit。HDR10 用这两个值作为全片唯一的静态描述；HDR10+ / Dolby Vision 则在此基础上叠加逐场景动态元数据。Typical values: MaxCLL ≈ 1,000–4,000 nits and MaxFALL ≈ 100–400 nits for cinema masters. HDR10 uses them as program-wide static descriptions, while HDR10+ and Dolby Vision add scene-level dynamic metadata.

亮度时间轴示意（横轴=时间，纵轴=亮度）Luminance timeline (x = time, y = luminance)

▬ MaxCLL（单帧峰值像素）MaxCLL (peak pixel) ▬ MaxFALL（帧平均亮度）MaxFALL (frame-average)

格式Format	传递函数Transfer	位深Bit depth	元数据Metadata	色域Gamut	生态Ecosystem	典型用途Typical use

7. 技术词汇表7. Technical glossary

理解 HDR 时，常见问题不是缺少参数，而是这些术语的边界混在一起。这里给出最短可用定义。The common difficulty in understanding HDR is not a lack of parameters but blurred boundaries between terms. These are the shortest useful definitions.

页面中的虚线词也可以悬浮查看解释。Hover over dotted terms elsewhere on the page for definitions.

OETF

场景光到电信号。摄像机或制作编码端使用。Maps scene light to an electrical signal; used by cameras or production encoders.

EOTF

电信号到显示光。监视器/电视的解码显示函数。Maps an electrical signal to display light; the decoding function used by a monitor or TV.

OOTF

场景光到显示光的整体系统观感，包含创作意图与观看环境补偿。The overall scene-to-display-light relationship, including creative rendering and viewing-environment compensation.

基于人眼感知的绝对亮度 EOTF，标准上限 10,000 nit。A perceptually designed absolute-luminance EOTF with a 10,000-nit standard ceiling.

HLG

相对 HDR 传递函数，暗部 gamma、亮部 log，适合广播兼容。A relative HDR transfer system with a gamma-like lower region and logarithmic highlights, suited to broadcast compatibility.

MaxCLL

整段内容中最高像素亮度，用于显示端判断高光映射。The highest pixel luminance in a program, available to displays when determining highlight mapping.

MaxFALL

最大帧平均亮度，反映一帧总体发光负载。The maximum frame-average luminance, describing the overall light level of the brightest average frame.

参考白Reference white

HDR 工作流中普通漫反射白或图形白的亮度锚点，BT.2408 推荐 203 nit。The luminance anchor for ordinary diffuse or graphics white in an HDR workflow; BT.2408 recommends 203 nits.

Headroom

显示峰值亮度高于参考白的余量，用于承载镜面反射、火焰、霓虹等局部高光。Display capacity above reference white, used for local highlights such as specular reflections, flames, and neon.

色彩体积Color volume

色域面积与亮度范围共同构成，决定“亮而有色”的可表达范围。The combination of gamut and luminance range that determines which colors can remain saturated at different brightness levels.

资料来源Sources

本地 PDF：HDR Production_210705.pdf，王亚明，《HDR制作、转换与播出》，2021。
Local PDF: HDR Production_210705.pdf, Wang Yaming, HDR Production, Conversion and Broadcast, 2021.
ITU-R BT.2100-3（2025-02）：HDR-TV PQ 与 HLG 图像参数值，最新版本。
ITU-R BT.2100-3 (2025-02): HDR-TV PQ and HLG image parameter values, latest edition.
ITU-R BT.2390-9：用于制作和国际节目交换的 HDR 电视技术报告。
ITU-R BT.2390-9: technical report on HDR-TV for production and international programme exchange.
ITU-R BT.2408-4：HDR 电视制作操作实践指南（含 203 nit 参考白规定）。
ITU-R BT.2408-4: operational practices for HDR-TV production (includes the 203-nit reference white).
ITU-R BT.2446-1：HDR 与 SDR 内容互转方法。
ITU-R BT.2446-1: methods for converting between HDR and SDR content.
ITU-R BT.1886：SDR 平板显示参考 EOTF（γ = 2.4）。
ITU-R BT.1886: reference EOTF for SDR flat-panel displays (γ = 2.4).

ITU-R BT.709 与 BT.2020：HDTV / UHDTV 色域原色与图像参数。
ITU-R BT.709 and BT.2020: HDTV / UHDTV gamut primaries and image parameters.
SMPTE ST 2084：PQ EOTF 规范；SMPTE ST 2086：母版显示色彩体积元数据（原色、白点、最大/最小亮度）；MaxCLL/MaxFALL 由 CTA-861.3 定义。
SMPTE ST 2084: the PQ EOTF spec; SMPTE ST 2086: mastering-display color volume metadata (primaries, white point, max/min luminance); MaxCLL/MaxFALL are defined by CTA-861.3.
SMPTE ST 2094-10：Application #1 的参数化色彩体积变换元数据；它不等同于 Dolby Vision 私有 RPU 语法。ST 2094-40：HDR10+ 使用的 Application #4 场景自适应动态元数据。
SMPTE ST 2094-10: parametric color-volume-transform metadata for Application #1; not the same as Dolby Vision's proprietary RPU syntax. ST 2094-40: the Application #4 scene-adaptive dynamic metadata used by HDR10+.
ARIB STD-B67：HLG 传递函数日本广播标准（BBC/NHK 联合提交基础）。
ARIB STD-B67: the Japanese broadcast standard for the HLG transfer function (basis of the joint BBC/NHK submission).
CUVA 005-2021 / HDR Vivid：中国超高清视频产业联盟动态元数据 HDR 标准。
CUVA 005-2021 / HDR Vivid: the China Ultra HD Video Industry Alliance's dynamic-metadata HDR standard.
HDR10+ Technologies、Dolby Vision、Dolby Vision Recommended Source Formats（Profile 8.4 HLG base layer）官方技术资料。
HDR10+ Technologies, Dolby Vision, and Dolby Vision Recommended Source Formats (Profile 8.4 HLG base layer) official technical material.
Google Chromium Blog: Bringing a clearer, more consistent HDR video experience to Chrome、SMPTE ST 2094-50 public committee draft repository 与 HDR10+ Technologies: Eclipsa Video Program：Eclipsa Video、Application #5、Reference White Anchor 与 Headroom-Adaptive Gain Curves 资料。
Google Chromium Blog: Bringing a clearer, more consistent HDR video experience to Chrome, SMPTE ST 2094-50 public committee draft repository, and HDR10+ Technologies: Eclipsa Video Program: material on Eclipsa Video, Application #5, Reference White Anchor, and Headroom-Adaptive Gain Curves.