色彩容量Color Volume

色彩容量是色域乘上亮度范围之后的总覆盖——五维体积图上「颜色那一角」的实测值，占的面积越大，能装下的颜色世界越大。

• 不只看色域：同样标 Rec.709，亮度上不去，容量照样小。
• 图上的读数：手机直出素材约 0.35，电影机 + RAW 约 0.85。
• AI 生成素材：按 sRGB/8bit 标，约 0.28——低于 709 实拍素材（见 AI 生成视频）。
• 一角塌，整块小：五维图的意义就是短板决定总面积。

Color volume is the total coverage after gamut multiplies luminance range — on the five-axis volume chart it is the real measure of the color vertex; the bigger the area, the bigger the color world it holds.

• Gamut alone is not enough: the same Rec.709 badge with no luminance headroom still means a small volume.
• Readings on the chart: phone footage sits around 0.35; a cinema camera shooting RAW reaches about 0.85.
• AI-generated footage: tagged sRGB/8bit, around 0.28 — below 709 camera material (see AI-Generated Video).
• One sunken vertex shrinks the whole area: that is the whole point of the five-axis chart.