Genesis

A Rust + egui NLE front-end built on the verified C engine from the Mojo MojoMedia project (FFmpeg decode/encode/audio + an OpenCL compute shim). Genesis rewrites only the app/UI layer; the engine stays C, called over FFI.

Why: the Mojo editor proved the engine (compositing, grade, scopes, keyframes — all numerically gated), but hand-rolling a GUI toolkit in Mojo over a bare GL backend hit ergonomic limits (no retained widgets/layout, no rounded-rects/gradients, manual hit-testing). egui supplies a mature immediate-mode toolkit (custom painting, interaction, theming, docking) with no C++ and no Qt. MojoMedia is preserved as the reference; we revisit Mojo as it matures.

Architecture — two processes (this is load-bearing)

genesis (ui/)              egui front-end. Links NO engine/OpenCL.
  │  spawn + read RGBA      chrome · timeline · interaction · theming · textures
  ▼
gcompose (gcompose/)       engine WORKER. Links the C engine, NO GUI libs.
  csrc/fpx_decode.c          FFmpeg decode (seek + EOF flush-drain)
  csrc/fpx_encode.c          FFmpeg encode (video + audio mux)
  csrc/fpx_audio.c/_aread.c  audio decode / filter-graph / program mix
  csrc/fpx_gpu.c             OpenCL composite / grade / PiP / filters / transitions / scopes
  → writes a GVW×GVH RGBA8 frame the UI uploads as an egui texture, and (persistent
    `--serve` mode) mixes program audio + answers scope queries over a line protocol

Why two processes (measured): initializing the NVIDIA OpenCL driver in the same process as eframe's GL/GLX driver intermittently segfaults at startup — ~20–40% across every in-process ordering we tried. The engine-only worker is ~stable, and the egui UI — which never calls OpenCL — is 0 crashes / 20. Isolating OpenCL in its own process removes the race by construction. (The worker still has a small residual init flake; the UI retries the spawn a few times, which makes the composite reliable — 15/15 with retry.)

Composited RGBA8 frames cross the process boundary as a raw file the UI reads. A persistent worker (gcompose --serve, a fixed-arity line protocol: PREVIEW/ENC/AUDIO/OPEN + scope queries) keeps decoder handles and the OpenCL context warm for preview, render, and audio assembly.

Capabilities (shipped + gated)

Genesis grew well past Phase 0 into a feature-rich NLE. Every item below was integrated through a build → behavioral-measurement → fold-regression gate before commit (see PARITY_GAPS.md for the source-grounded Shotcut coverage audit and per-wave gate numbers).

• Timeline / editing — arbitrary V/A tracks; drag-move, edge-trim, split, ripple/slip/roll/slide, razor-all-tracks, frame-nudge, snap, markers, clip grouping, replace-clip, detach-audio, paste-filters, freeze-frame, export in/out region, multi-level undo/redo; interactive track headers (rename / hide / mute / lock / add / remove); on-clip fade + transition-length drag handles; audio align (waveform cross-correlation auto-sync); nested sequences (compound clips). A timeline toolbar surfaces these edits as icon buttons (split / razor-all / lift / ripple / cut / copy / paste / append / overwrite / insert / marker / snap toggle / zoom in-out-fit), each firing the same code path as its keyboard shortcut. New clips (Add-as-clip / drag-drop) are length-clamped to their source frame count (engine NFRAMES query) so a clip never references frames past the media end.
• Compositing — N-layer video fold, V2-over-V1, per-clip PiP transform (+ keyframes), 8 blend modes, per-clip fades (audio + video fade-to-black), chroma key + spill suppression, shape mask (rect/ellipse + feather/invert).
• Transitions — 11 per-boundary (crossfade / wipes / slide / zoom / dissolve / iris / clock / barn-door).
• Colour & grade — bright/contrast/sat, lift-gamma-gain, curves, HSL, levels, white balance, selective colour (per-hue band), gradient map, solarize, colour temperature.
• Video filters (~36) — stylize (vignette/sharpen/flip/invert/sepia/grayscale/posterize/mosaic/ halftone/emboss/edge), FX (denoise/glow/RGB-shift), old-film (grain/scratches/diffusion), distort (wave/swirl/threshold/lens/crop/glitch/mirror/kaleidoscope/dither), 360 reframe, per-clip speed/time-remap + reverse.
• Audio — ~18 effects (3-band + 10-band graphic EQ, pan, compress/gate/normalize, reverb/delay/ pitch, lowpass/highpass/tremolo, bass/treble/notch/chorus, flanger/phaser/limiter); a per-track mixer (fader / pan / mute / solo, every track); master gain automation (volume envelope).
• Keyframes — 36 MLT interpolation types (discrete/linear/smooth + Catmull-Rom variants + easings); per-clip filter-parameter keyframing.
• Scopes — RGB histogram, luma waveform, vectorscope, RGB parade, audio peak+RMS meter, audio spectrum (FFT), audio waveform oscilloscope — in a resizable tabbed right dock (Properties / Scopes / Audio) so each group gets the full panel instead of one crammed column.
• Monitors — Program + Source (3-point) preview panes, each with a transport bar (skip-to-start / rewind / play-pause / fast-forward / skip-to-end + SMPTE HH:MM:SS:FF timecode) and a scrub slider beneath the image.
• Subtitles — timeline-wide timed captions (import SRT / edit) rendered over the program.
• Media management — media-pool thumbnails (decoded first frame per item), 3D-LUT library (browse a .cube folder), recent-files menu, media bins (organize the pool), media relink (fix missing files).
• Export — codec / CRF / GOP / preset, audio codec (aac/mp3/ac3/pcm) + bitrate, in/out region.
• Project — serde-JSON save/load (round-trip exact); periodic auto-save + crash recovery.
• UI chrome — File/Edit/View/Help menu bar (alternate entry to the same actions), top toolbar, timeline toolbar, tabbed resizable right dock (Properties / Filters / Scopes / Audio), maximized 4K window.
• Filters dock — Shotcut-style per-clip filter stack over the existing effect fields: an "Applied" list (each removable with ✕ = reset) + a searchable "Add filter" catalog (BCS, color wheels, white balance, transform, blur, curves, HSL, levels, vignette, sharpen, flip, simple FX, mosaic, gradient map, denoise, glow, RGB-shift, halftone, chroma key, look). Parameters are tuned in the Properties tab; one undo step per add/remove. UI-only — a clip at defaults renders unchanged.

Build / run

cargo run -p genesis --release -- [/path/to/media.mp4]   # default: /tmp/editor_clip.mp4

Deps: a C compiler + FFmpeg dev libs (libavformat/avcodec/swscale/avutil), OpenCL (libOpenCL + CL/cl.h, here from CUDA), and the egui/winit system libs (GL, xkbcommon). The genesis binary locates gcompose next to itself in the target dir.

Headless gate hooks (env-driven, for measurement)

GENESIS_OPEN=<project.json> opens a project at launch; GENESIS_RENDER=<out.mp4> renders it then exits; GENESIS_SHOT=<ppm> captures egui's framebuffer; GENESIS_SOURCE=<idx> opens the source monitor; GENESIS_SPECTRUM/GENESIS_SAMPLES=<out> dump audio-scope buffers; GENESIS_ALIGN=<out> runs the audio-align cross-correlation. The engine worker (gcompose --serve) speaks a line protocol (PREVIEW/ENC/AUDIO/OPEN + CLIPAUD/scope queries).

Status

Active. Engine C vendored from MojoMedia/ffi; icon blob assets/icons_dark_32.rgba (39 Shotcut dark icons). The window opens maximized. The two-process OpenCL-isolation design (above) is stable with worker-spawn retry — a live worker's ERR reply (a legitimately-failed command, e.g. a thumbnail for a source frame past a clip's media end) is now a soft miss, so it no longer triggers the worker+OpenCL restart cycle that machinery reserves for a genuinely dead worker. The video decoder (fpx_decode_frame_letterbox) tracks its position and decodes forward without seeking for sequential/in-GOP access (playback + render), via a frame-accurate drain-first loop — a ~4× per-frame speedup over re-seeking to a keyframe every frame, byte-identical to the seek path (random access / backward scrubbing still seeks). Editing, compositing, audio, scopes, export, project/media management, subtitles, and nested sequences are complete (each shipped through a build → behavioral-measurement → fold-regression gate; see PARITY_GAPS.md). A 2026-07-15 review pass fixed 7 defects (export to a path with a space silently aborted; wrong-clip edit after a track-remove / split-with-multi-select; an empty-tracks paint crash; two engine resource leaks; non-undoable Properties track ops — see HANDOFF.md §10). The remaining Shotcut gaps need a new subsystem or hardware this box lacks — proxy editing + speech-to-text (transcode pipeline / a model), HW encoders / RNN denoise (env-blocked), and low-value export knobs (two-pass / B-frames / 10-bit / rich text). docs/ROADMAP.md records the original P1–P10 build-out (all complete).