Pure-R 'OpenTimelineIO' Document Model

A dependency-light 'OpenTimelineIO' (OTIO) < https://github.com/AcademySoftwareFoundation/OpenTimelineIO> document layer in pure R. Provides constructors for the OTIO object model (timelines, tracks, clips, gaps, media references, rational times and time ranges), functional builders that return new objects, and readers and writers for canonical '.otio' files through 'jsonlite'. The optional 'RcppOTIO' package validates output against the real 'OpenTimelineIO' C++ library. No compiled code.

rotio

A pure-R OpenTimelineIO (OTIO) document model. Constructors for the OTIO object model (Timeline, Track, Clip, Gap, media references, RationalTime, TimeRange), functional builders that return new objects, the edit algorithms (overwrite, insert, trim, slice, slip, slide, ripple, roll, fill, remove), schema upgrade/downgrade hooks, and readers and writers for canonical .otio JSON through jsonlite. Directory bundles (content.otio + media/) are covered by read_otiod() / write_otiod().

No compiled code. The only hard dependency is jsonlite.

Relationship to RcppOTIO

RcppOTIO wraps the OTIO C++ library itself (Rcpp over libopentimelineio). rotio is the lightweight sibling: same object model and naming, implemented entirely in R.

rotio lists RcppOTIO in Suggests as a validation oracle: the parity tests serialize rotio's output through real libopentimelineio and check the JSON and edit-algorithm behavior match the reference implementation. The oracle is optional. Without RcppOTIO installed, the full test suite still passes and the parity tests skip, so rotio runs anywhere R runs, no C++ toolchain needed.

Parity testing these packages against libopentimelineio is what surfaced OpenTimelineIO#2025, an upstream edit-algorithm fix.

Install

remotes::install_github("cornball-ai/rotio")

The optional oracle (needs the OpenTimelineIO C++ library >= 0.18 and Imath headers installed):

install.packages("RcppOTIO", repos = c(
  "https://cornball-ai.github.io/drat",
  "https://cloud.r-project.org"
))

Example

library(rotio)

ref  <- ExternalReference("shot.mov")
clip <- Clip("shot", ref,
             source_range = TimeRange(RationalTime(0, 24), RationalTime(48, 24)))
trk  <- add_child(Track("V1", kind = "Video"), clip)
tl   <- add_track(Timeline("my timeline"), trk)

find_clips(tl)            # list of clips, recursively
js  <- to_json_string(tl) # canonical OTIO JSON
tl2 <- from_json_string(js)

With RcppOTIO installed, validate_with_RcppOTIO(tl) round-trips the JSON through libopentimelineio to confirm real OTIO accepts it.

License

Apache License 2.0, matching upstream OpenTimelineIO.