L1 / L2 trims (trim pass)

In Dolby Vision, L1 is the automatic per-shot analysis: the minimum, mid (average) and maximum luminance Dolby measures from each shot, which drives the base mapping to any target display. You generate it by running an analysis across the timeline. L2 trims are the colorist’s manual adjustments authored for a specific target display — most importantly the 100-nit Rec.709 SDR target — telling the mapper “when you map my HDR grade down to SDR, lift this shadow, pull this specular back, add a touch of saturation.” An L2 trim is not a re-grade and not a new file; it’s guidance stored as metadata that the CMU obeys. Good L2 SDR trims are what make a derived SDR master look intentional rather than machine-crushed. (Finer levels — L3, L5, L8 — exist; L1 analysis plus L2 SDR trims is the working core.)

First used in: 3.7 · Dolby Vision & derived deliverables