dot-prerender_sources: Pre-render still-image and image-sequence clips into video

In compost: Video Compositing via 'FFmpeg'

Pre-render still-image and image-sequence clips into video

Description

A still image has no intrinsic duration or motion, and an ImageSequenceReference has no single file: both are encoded into temporary video clips here, so everything downstream (concat, crossfades, framing, captions, audio) handles only video. Stills go through still_clip at the source_range's rate, covering the media window up to the range's end (so a preceding dissolve keeps its head handle), rastered to the source aspect fitted inside the framing box, and animated by the clip's cornball.* motion effects. Sequences go through frames_clip at the reference's own rate; motion effects are not applied to them (a drawn sequence animates itself). Video files pass through untouched.

Usage

.prerender_sources(seq_v, framing, media_dir = NULL)

Arguments

seq_v	A .video_sequence() result.
framing	The timeline framing list, for still rastering.
media_dir	Base directory for relative urls, or NULL.

Value

list(files, temps): files with pre-rendered replacements, and the temp paths for the caller to clean up.

compost documentation built on Aug. 4, 2026, 5:11 p.m.