Transitions

--transition KIND:DURATION[:MIN-CUT] puts a transition at each cut auto-editor makes, and at the start and end of the timeline. The video and audio transitions are linked: they cover the same span.

auto-editor video.mp4 --transition dissolve:1sec        # cross-dissolves, fades at the ends
auto-editor video.mp4 --transition push:0.5sec          # a Premiere Pro transition
auto-editor video.mp4 --transition clock-wipe:1sec:0    # at every cut, however short
auto-editor video.mp4 --transition constant-power:1sec  # audio crossfade kind; video dissolves

• DURATION: how long each transition lasts (0.5sec, or a bare frame count).
• MIN-CUT (default 1sec): skip cuts whose removed source is shorter than this, so trimming a short pause stays a hard cut instead of a stutter. 0 transitions at every cut.

A transition draws on the footage that was cut out (its handles), so:

• it may be shortened, or skipped, when a clip or the removed stretch is too short to support it;
• whatever was in the removed stretch shows mid-transition. If that's filler you don't want seen, keep transitions short or raise MIN-CUT.

Kinds

Every transition Premiere Pro has, under its Premiere name in lowercase with dashes. Those in its Legacy folder that share a name with a newer one end in -legacy. They play at Premiere's default settings.

dip-to-color dips to the timeline's background color (-bg).

Audio. A video kind gives the audio a plain crossfade. Audio has three kinds of its own: dissolve (Premiere's Constant Gain; constant-gain is accepted too), constant-power and exponential-fade. Naming one of those keeps the video a cross-dissolve.

How close to Premiere. auto-editor renders every kind itself. Compared frame by frame with Premiere's own renders, push, clock-wipe and barn-doors match to within encoding noise and page-peel is close; the others haven't been measured. Expect simple dissolves and wipes to be near, and effects like glitch or light-leak, which draw their own noise and colors, to differ. For Premiere's exact look, export with premiere-otio and let Premiere render them.

Per-transition control: v3 timelines

--transition uses one kind everywhere. For a different kind or length at each cut, export a v3 timeline, edit its transitions key, and render it:

auto-editor video.mp4 --transition dissolve:0.5sec --export v3 -o edit.v3
# edit edit.v3, then:
auto-editor edit.v3 -o out.mp4

"transitions": {
  "v": [[{"kind": "push", "at": 300, "dur": 15, "alignment": "center"}]],
  "a": [[{"kind": "constant-power", "at": 300, "dur": 15, "alignment": "center"}]]
}

at is the edit point in timeline frames, dur the length in frames, and alignment is start (a fade in from a clip's start), center (across a cut between adjacent clips) or end (a fade out at a clip's end). Video tracks take video kinds; audio tracks take dissolve, constant-power or exponential-fade. See https://auto-editor.com/docs/v3.

In editor exports

To bring the kinds into Premiere, use premiere-otio. v1, v2 and clip-sequence exports drop transitions; a clip sequence's files are separate, so a transition between them has no meaning.

Importing

FCP7 XML and FCPXML imports read the transitions those formats name: Cross Dissolve, Additive Dissolve, Dip to Color Dissolve (black or white by its color), Edge Wipe, the Irises, Page Curl, Star, Cross Fade (0dB/+3dB), and Premiere's names generally. A name it doesn't know plays as a dissolve.

Recipes

auto-editor talk.mp4 --transition dissolve:0.3sec           # soft cuts in a talking-head video
auto-editor vlog.mp4 --transition whip:0.4sec:2sec          # whips, only where 2s+ was removed
auto-editor podcast.mp3 --transition constant-power:0.2sec  # audio-only: smooth crossfades
auto-editor video.mp4 --transition push:0.5sec --export premiere-otio   # finish in Premiere

For cutting itself (edit methods, margins, pace), see the auto-editor skill. For editor exports in general, see the auto-editor-export skill.