effectcraft/docs/file-format-parity.md

# File format parity

> **Last reviewed:** 2026-10-19 · **Last updated:** 2026-11-05 · **Change:** ProRes alpha final-run conformance; previously `.aep` / `.aepx` import and `.aep` export (`crates/aep`: `container`, `import`, `export`) · **Target:** Adobe After Effects 2026

Every format After Effects reads or writes, with EffectCraft's support. After Effects' list comes
from its installed bundle (26.5.0.89: `Info.plist` `CFBundleDocumentTypes`, `Plug-ins/Format`,
`Resources/usd_plugins`) and its public documentation; ours from `crates/media/src/lib.rs`
(`STILL_EXTENSIONS`, `VIDEO_EXTENSIONS`, `MODEL_EXTENSIONS`, FilmCraft's `AUDIO_EXTENSIONS`),
`crates/engine/src/commands/file.rs` (`DATA_EXTENSIONS`) and `OutputFormat::ALL` in
`crates/project/src/render_queue.rs`. Video codecs come from FilmCraft's pure-Rust crates
([architecture.md](architecture.md)).

**Overall ≈ 50%** (estimated, weighted by use): modern delivery and interchange formats are
strong, but After Effects' own formats, which decide whether existing work moves over, are the
weakest: `.aep` / `.aepx` import and export are partial, templates and presets are 0%.

Fidelity key: **exact** (bit-exact or within a stated tolerance of a reference), **good** (round
trips and renders, checked by tests, not against After Effects), **partial** (named limitations),
**none**.

## After Effects' own formats

| Format | After Effects | EffectCraft read | Write | Fidelity / notes | Tested by |
|---|---|---|---|---|---|
| Project `.aep` | R/W (native) | partial | partial | Main file format; the clean-room method is in [aep-format.md](aep-format.md), the maintainers' decision on it is open (#190). `crates/aep` reads and writes the RIFX container losslessly (byte-identical round trip) with a typed view of the decoded fields, from our own generated files only ([aep-format.md](aep-format.md)). File ▸ Import ▸ After Effects Project… (`file.importAep`, `effectcraft_aep::import`): folders, project settings, compositions, every layer kind, Transform, keyframes, expressions, masks, text with animators, shapes, cameras, lights, track mattes, markers, time remapping, layer styles, the built-in effects of a table shared with the exporter (Curves, Levels, Glow, Fractal Noise, Gradient Ramp, … and the expression controls), footage and image sequences; everything else is reported ([aep-import.md](aep-import.md)). File ▸ Export ▸ After Effects Project… (`file.exportAep`, `effectcraft_aep::export`) writes the same scope with every chunk built in code; exports were opened and read back in After Effects 2026 ([aep-export.md](aep-export.md)); everything else is reported. Effects outside the table (plug-ins, Lumetri, …) are not converted | `crates/aep` tests (`tests/container`, `tests/import`, `tests/export`) |
| XML project `.aepx` | R/W | partial | none | Read into the same chunk tree as `.aep` by `crates/aep` (`read_aepx`; mapping in [aep-format.md](aep-format.md) section 1), so `file.importAep` imports it with the same coverage as `.aep`; not written | `crates/aep` `aepx` tests (container and import) |
| Templates `.aet` / `.aetx` | R/W | none | none | Own `.ectemplate` (Home ▸ Templates, Save as Template) | `templates.rs` tests |
| Motion Graphics template `.mogrt` | W (and R in Premiere) | none | none | Own `.ectemplate` Essential Graphics templates; FilmCraft rejects our `.fcgt` export (#611) | `essential.rs` tests |
| Animation preset `.ffx` | R/W, 621 bundled | none | none | Own JSON `.ecpreset`; `.ffx` is out of clean-room scope (AGENTS.md §2) | `animation.rs` tests |
| Render Settings / Output Module templates `.ars` / `.aom` | R/W | none | none | Templates are stored in the project and settings instead | `render_templates.rs` tests |
| Scripts `.jsx` | R (run) | yes | — | After Effects object model and ScriptUI ([scripting-parity.md](scripting-parity.md)) | `crates/script` tests |
| Binary scripts `.jsxbin` | R (run) | none | — | No public specification: out of scope | — |
| Motion graphics JSON `.mgjson` | R (data) | none | none | Media Browser lists it; import accepts only `.json` / `.csv` / `.tsv` data | — |
| Captions `.aecap`, graphics `.aegraphic` | R/W | none | none | — | — |
| Native `.ecproj` | — | yes | yes | Versioned JSON; schema migrations tested; absolute footage paths, no relinking (gap 18) | engine project tests |

## Footage: stills

| Format | After Effects | Read | Write | Fidelity / notes |
|---|---|---|---|---|
| PNG | R/W | yes | yes (sequence) | good |
| JPEG | R/W | yes | yes (sequence) | good |
| TIFF | R/W | yes | yes (sequence) | good |
| OpenEXR (multi-layer, Cryptomatte) | R/W | yes | yes (scan-line sequence, half or 32-bit float, every compression but HTJ2K) | good; written files carry a `chromaticities` attribute for the output space's primaries and white; HTJ2K compression fails (#482); a multi-layer frame decodes once for its picture and EXtractoR / Cryptomatte from the first frame on, except Media Replacement items, which are learned at their first frame, and files whose picture the `image` crate still decodes (#474); footage alone keeps only its picture's channels, though a single-part file still decompresses every channel's pixels; decoded channels are held as f32 |
| Photoshop PSD / PSB | R (footage, composition) / W (layers, sequence) | yes (layers, groups, masks, styles, smart objects) | Save Frame As ▸ Photoshop Layers; no Photoshop sequence output | good, from Adobe's published spec |
| Illustrator `.ai`, PDF, EPS | R | yes (vector, Continuously Rasterize, Create Shapes; Composition and Composition - Retain Layer Sizes, #1536) | — | partial: no JPX / JBIG2 images, no Illustrator procset EPS |
| SVG | R | yes | — | good; SVG markup on the clipboard pastes as a shape layer (26.3, #738); Illustrator's own clipboard data (PDF/AI) doesn't |
| GIF | R/W | yes | yes (animated) | good |
| BMP | R | yes | — | good |
| WebP | — | yes (still; animated WebP as footage with its frames, timing and alpha, #762) | — | beyond After Effects |
| Targa `.tga` | R/W | yes (still and sequence; alpha interpreted on import) | yes (sequence; uncompressed 24-bit RGB or 32-bit RGB + Alpha, straight or premultiplied) | good: import (#745); output reads back through it unchanged; the alpha is not labelled in the file (no TGA 2.0 extension area), so it is interpreted on import |
| DPX / Cineon `.dpx` `.cin` | R/W | yes (still and sequence; 8/10/12/16-bit luma, RGB, RGBA, both byte orders; log code values shown as stored, or converted by Interpret Footage ▸ Cineon Settings ▸ Logarithmic Conversion) | none | partial: import (#756) and Cineon Settings; no DPX output; common in film VFX |
| Radiance `.hdr` | R/W | yes (still and sequence, 32-bit linear float like OpenEXR) | none | good for import (#745); no Radiance output |
| SGI, PICT, ElectricImage, RLA/RPF images | R | none | none | Legacy; RPF camera data import exists (`keys.rpfCameraImport`) |
| Camera Raw (DNG, CR3, NEF…) | R (Camera Raw) | none | none | LightCraft has decoders that could be shared |
| HEIF / AVIF | R (platform) | none | none | — |

## Footage: video and audio

| Format | After Effects | Read | Write | Fidelity / notes |
|---|---|---|---|---|
| MP4 / MOV with H.264 | R/W | yes | yes (own encoder, + AAC) | decoder bit-exact on conformance streams (FilmCraft) |
| HEVC (H.265) | R/W | yes | yes (MP4 `hvc1`, Main / Main 10) | encoder bit-exact with ffmpeg's decode; no B-frames / SAO, larger files |
| AV1 | R | yes | yes (MP4 `av01`, WebM) | beyond After Effects' export; no B-frames / CDEF |
| Apple ProRes (422 family, 4444) | R/W | yes | yes | alpha final-run syntax checked in exported MOVs (#293); 4444 colour tag wrong (#340); no ProRes RAW |
| WebM / Matroska (VP9, AV1, Opus) | R (limited) | yes, incl. VP9 alpha | yes | beyond After Effects |
| MXF (OP1a / OP-Atom) | R/W | yes (FilmCraft's demuxer: AVC, MPEG-2 incl. XDCAM / D-10, VC-3 / DNxHD, ProRes; PCM audio) | none | partial: import (#767), checked against ffmpeg; no MXF output |
| AVI | R | yes (FilmCraft's demuxer: AVI 1.0 / OpenDML; Motion JPEG, H.264, HEVC, uncompressed; PCM, MP3, MP2, AC-3 audio) | none | partial: import (#1701), checked against ffmpeg; H.264 needs its parameter sets in the chunks (global headers and copies with an `avcC` record don't decode until storytold/filmcraft#2303), and a damaged video index loses the video (storytold/filmcraft#2302); DV, MPEG-4 Part 2 (DivX / Xvid) and other legacy codecs import but show why they have no picture; no AVI output |
| DNxHD / DNxHR | R/W | unverified (FilmCraft decodes it; reachable only inside `.mov`) | none | — |
| BRAW, R3D, ARRIRAW | R (plug-ins / SDKs) | none | none | proprietary SDKs |
| Variable-frame-rate phone video | R | unverified | — | needs a real-media corpus |
| WAV, AIFF | R/W | yes | yes (16-bit PCM) | good |
| MP3, AAC / M4A, FLAC, Ogg, Opus | R | yes | AAC and Opus inside video only | MP3 silence (#324) is closed |

## 3D models

| Format | After Effects 26 | Read | Notes |
|---|---|---|---|
| glTF / GLB | R | yes (meshes, PBR, skins, animations) | good |
| OBJ / MTL | R | yes | good |
| FBX | R (`usdFbx`) | yes (7.x binary and ASCII: meshes with normals, UVs and per-polygon materials, the Model hierarchy with pivots and pre/post rotation, Lambert/Phong materials with embedded or relative textures, axes turned to Y-up; no animation, skinning, cameras or lights; 6.x rejected) | partial |
| USD / USDZ | R (`usd_plugins`) | none | gap 13 |
| STL | R (`usdStl`) | yes (binary and ASCII, VisCAM and Magics facet colours; Z-up turned to Y-up) | good |
| Substance 3D materials `.sbsar` | R (26.0) | none | gap 13 |

## Interchange and data

| Format | After Effects | Read | Write | Notes |
|---|---|---|---|---|
| Premiere Pro `.prproj` | R (import) | none | none | Out of clean-room scope pending a decision; we interchange through FCP7 XML, FCPXML, OTIO, EDL, AAF and OMF instead (beyond After Effects) |
| Lottie JSON / dotLottie | via third-party plug-ins | yes | yes | beyond After Effects; a warnings list names what Lottie can't express |
| JSON / CSV / TSV data | R | yes (`footage()`, data layers) | — | good |
| LUTs (`.cube`, `.3dl`, `.csp`, `.spi1d/3d`, CDL) | R | yes (Apply Color LUT, OCIO effects) | — | Apply Color LUT bug (#514) is closed |
| OpenColorIO configs | R (OCIO 2.5.1, ACES 2.0 in 26.5) | yes (OCIO v2 subset, Blender configs) | — | partial: no ACES 2.0 output transforms |
| Fonts (TTF, OTF, TTC, variable) | R | yes | — | good |
| Mocha shapes | R (Mocha AE) | own documented JSON | — | Mocha's format is not public |
| Vanishing Point `.vpe` | R | none | — | no public specification; the menu entry explains why |

## Render queue outputs (`OutputFormat::ALL`, 14)

H.264 MP4, HEVC MP4, AV1 MP4, ProRes MOV, uncompressed 8-bit RGB / RGB + Alpha MOV (`raw `, + PCM;
#372), WebM (VP9 or AV1 + Opus), PNG / JPEG / TIFF / OpenEXR / Targa sequences, animated GIF, WAV, AIFF.
OpenEXR sequences are scan-line RGBA files in half or 32-bit float (default) with None, RLE, ZIPS,
ZIP (default), PIZ, PXR24, B44, B44A, DWAA or DWAB compression; PXR24 on float, B44 / B44A on half
and DWAA / DWAB are lossy (#2911). No tiled or multi-part output, no HTJ2K (the `exr` crate can't
write it).
Missing against After Effects + Media Encoder: 16-bpc uncompressed, AVI and lossless-compressed
single-file video (Animation / PNG codecs), DPX / Photoshop sequences, MXF, DNxHR, hardware
encoders ([hardware-parity.md](hardware-parity.md)), and rendering safely over an existing file
(#325).

### Render source protection

The render queue refuses an output that would replace footage, an attached proxy, or the
project file. It checks every output module and segment before dispatching the item. A refused
item is marked Failed with its reason; other valid queued items can still render. Render logs
are checked too. No render parameter overrides this protection.

Checks compare normalized paths and native file identities, so an existing symbolic link,
hard link, junction or Windows short name cannot disguise a source as another output file.
Source identities are indexed once per check and matching identities are verified. The index
does not keep file handles open for the lifetime of a long sequence.

Default output names move aside when they would replace a protected file. This also applies to
Create Proxy: recreating a proxy chooses a new default name and attaches the new proxy, leaving
the previous proxy file intact. An explicit output path is kept as entered and refused if it
would replace a protected file.

After Pre-render imports its result, that file is footage too. Re-queueing the same item
with the same output is refused; run Pre-render again for a fresh default output, or choose
another Output To. An item's `last_output` is not permission to replace imported footage.

Image-sequence checks inspect existing frames in the requested range. Skip Existing Files leaves
existing frames alone. If a frame number appears in a folder name, the checker probes each
frame separately and refuses ranges over 100,000 frames instead of silently checking a prefix.
Choose a fixed output folder or a shorter range for those exports.

This guard does not introduce an overwrite flag, confirmation dialog, or changed replacement
defaults for the CLI, scripts or MCP. Replacement consent and staging ordinary output files
belong to the exporter. The source check runs before export; filesystem changes between that
check and a write still require exporter-side revalidation.

## Estimate

**≈ 130–230 h**: `.aep` / `.aepx` 80–160 h (import and export of the common scope are in `crates/aep`; the rest is in [aep-import.md](aep-import.md)), wiring TGA / DPX /
HDR / MXF / AVI / DNx import and DPX output 10–20 h, FBX animation and skinning, USD and Substance 20–40 h,
relinking 6–12 h, `.mogrt`-compatible templates 15–30 h (partly parallel with the rest).

## Revision history

| Date | Change | Summary |
|---|---|---|
| 2026-11-05 | minor | ProRes encoder pin and export regression for final alpha runs; native macOS decode validated, Resolve still unverified (#293) |
| 2026-10-30 | minor | Render-queue source-protection behavior and limits consolidated here from the standalone page |
| 2026-10-12 | minor | #324 and #514 marked closed; open `.aep` PRs #251 and #860 noted |
| 2026-10-10 | major | First file format parity document, from the After Effects 26.5 bundle and this repository's import/export registries |