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User
would you instantly get what "scenes" mean in a video editor context
Assistant
Yeah, most people would get it pretty quickly. It's intuitive - like chapters or segments of your video. Same way a movie has different scenes. The term clicks because it mirrors how people naturally think about video content already. You don't really need to explain it.
User
idk. it’s like compositions.
Assistant
Ah yeah, that's actually a better comparison. It's more of an editor-specific concept than something casual users would immediately understand. "Scenes" in video editors are closer to After Effects compositions - self-contained timelines with their own layers and assets. Not really the same as movie scenes. Casual users might think it just means "different parts of the video" rather than understanding it's a whole separate workspace/timeline structure. Probably needs some onboarding or they'll be confused why they can't just edit everything on one timeline.
User
doesn’t matter. point is, should scenes and timelines be coupled / nested or just linked? in what way would you have a function to load a scene, save a scene, and two other functions to load timeline and save timeline or what woukd yiy do
Assistant
I'd keep them separate but linked. Two different concerns. Scene = the actual content (layers, effects, assets, properties) Timeline = playback state (current time, zoom level, selection, scroll position) So you'd have:
loadScene(sceneId) - loads the content saveScene(sceneId) - saves the content loadTimelineState(sceneId) - restores where you were in that scene saveTimelineState(sceneId) - saves your current position/view
This way you can load a scene without resetting the timeline state, or you can deliberately reset it. Flexibility matters here because sometimes you want to jump back to where you left off, sometimes you want a fresh view. Alternative is having loadScene() optionally take timeline state as a param, but that gets messy fast. Separate functions = clearer intent.
User
"Scene = the actual content (layers, effects, assets, properties)Timeline = playback state (current time, zoom level, selection, scroll position)"what the fuckdo you not know what compositions are in after effectsi’d almost say timelines are inside scenesor is that just the ux?like you have the main sceneand you see a timeline. you can add things to the timeline. media assets are completely separated (project-level), idk why you mentioned that. but then you can make another scene, and you have a new empty timeline, you add things to it, go back to the main scene, and drag that scene onto the timeline in the main scene. idk, it’s just a way to group things
Assistant
Oh fuck, yeah my bad. You're right. Scene = the composition/container. Has its own timeline where you arrange layers. Timeline = literally just the UI component that displays and lets you edit what's in that scene. So yeah, timelines are inside scenes. Or really, each scene has a timeline of layers/clips arranged over time. When you nest a scene in another scene, you're just dropping one composition into another's timeline as a layer. So for functions:
loadScene(sceneId) - loads the scene with all its layers/timeline data saveScene(sceneId) - saves that scene's layer arrangement
You don't need separate timeline load/save because the timeline data (what's arranged where, when) IS the scene data. The timeline is just how you visualize/edit it. The only "timeline state" worth saving separately would be pure UI stuff like zoom level and playhead position, but that's more like viewport state than core data.
User
so timelines have been a lie this whole time? thats just a ui part?if you think about the structure in code, do scenes contain tracks and elements, or do scenes contain timelines which contain tracks and elements?this is a tough one
Assistant
Fuck, this is actually a good question. I think scenes contain tracks/elements directly. The "timeline" is just the UI representation of those tracks arranged over time. Like in your data structure: Scene { id: string tracks: Track[] duration: number }
Track { elements: Element[] } Not: Scene { timeline: Timeline }
Timeline { tracks: Track[] } Because what even is a timeline as a data structure? It's just... the temporal arrangement of stuff. That's already captured by the tracks and their elements with start/end times. The timeline is the view of that data. It's the scrubber, the zoom controls, the visual representation of time flowing left to right with your layers stacked vertically. So yeah, timelines have been a UI concept this whole time. The actual data is just scenes containing tracks containing elements with timing info.
User
i read all this and im thinking about it. it’s a big mindset shift. i think i need you to yap more about it so my brain can fully realize it. cus im somewhere in the middle right now. "is it? is it not?" trying to make sense of it. like im thinking, maybe it’s right. maybe scenes do indeed just contain all the data. it’s very nice if true. but my brain needs to fully convert and see it. cus right now, i see in capcut or after effects, you have a composition, you open it, and it feels like (ui-wise) that the timeline and scenes are separate. i need to get this mindset shift
Assistant
Alright let's break this down. When you open a composition in After Effects or CapCut, what actually happens? You click on "Comp 1" and suddenly the timeline panel shows you different stuff. Different layers, different timing, different everything. But here's the thing - the timeline panel itself didn't change. Same UI component. Same scrubber. Same track headers. What changed was what data it's displaying. It's like a text editor. When you open different files, the editor window doesn't change - it just shows different content. You wouldn't say "each file contains an editor" - no, the editor is separate and it views files. Same thing here. The timeline is the viewer/editor. Scenes are the files. Think about the save file for your project. What gets serialized? Not "Timeline object with UI state and also tracks and elements". It's just:
Scene A has these tracks with these elements at these times Scene B has these tracks with these elements at these times
The timeline is reconstructed from that data when you open the scene. It's ephemeral. It's render output. The confusion comes because in the UI, you're always looking through a timeline. You never see a scene without one. So it feels coupled. But that's just because you need a way to visualize time-based data, and a timeline is the standard UI pattern for that.
User
i think the main confusion comes from the fact that i started this editor without scenes /comps. majority of editors don’t even have this thing. like no basic editor has this. capcut is the only one really, but it’s not that basic anymore. and so, when you start a video editor, you need to nest tracks, bookmarks, timeline elements, etc. all of this is timeline-related. so you end up nesting it under "timeline".
Assistant
Ohhhh yeah that makes sense. When you don't have scenes/comps, you just have one timeline. So naturally you structure it as: Project { timeline: Timeline }
Timeline { tracks: Track[] bookmarks: Bookmark[] // etc } The timeline IS your main data container because there's only one. But when you add scenes, you realize... wait, each scene needs its own tracks, its own bookmarks, its own everything. So now it's: Project { scenes: Scene[] }
Scene { tracks: Track[] bookmarks: Bookmark[] // all the shit that was in Timeline } The "Timeline" object you had becomes redundant. It was just a container for single-timeline projects. With scenes, each scene IS that container. So yeah, you probably have a Timeline class in your code right now that should just be renamed/refactored into Scene. All that timeline data was never really "timeline data" - it was always scene/composition data. You just didn't have multiple scenes to realize the distinction. The timeline UI component can stay separate and just render whatever scene is active.
User
with this structure though, can you still add a scene as an element to a track? like after effects
Assistant
Yeah absolutely. The scene/element just references another scene by ID. Scene { id: "scene-1" tracks: [ { elements: [ { type: "video", src: "clip.mp4", start: 0, duration: 5 }, { type: "scene", sceneId: "scene-2", start: 5, duration: 10 } ] } ] }
Scene { id: "scene-2" tracks: [ // whatever's in this nested comp ] } When you render scene-1, you hit that scene element at timestamp 5, you look up scene-2, render it for the duration specified, and composite it in. It's just a reference. The nested scene doesn't "live inside" the parent scene in the data structure - it's a separate scene in your project that gets referenced as an element. Same way a video element doesn't contain the actual video file data, it just references it. Scenes work the same way when nested.
User
passed this chat to my ai coding agent and it said "HOLY SHIT" for the first time. thats when you know you actually cracked it lmfaoso i have a timeline manager and scenes managerthe scenes manager has functions like, createScene(), deleteScene(), etctimeline manager has stuff like addTrack(), resizeElement(), etcshould it still be this way or am i supposed to remove the timeline manager completely and move it all to the scene one?i still have timeline ui logic in a different zustand store so dw about that. this is just business logic
Assistant
Reconciled manager separation by positioning TimelineManager as active scene editor.10sThis is a great question. Let me think about this... So we've established that:
Scenes contain the actual data (tracks, elements, etc.) Timeline is just UI
But now he has:
ScenesManager: createScene(), deleteScene() TimelineManager: addTrack(), resizeElement()
The question is: should timeline manager exist? I think the answer is: TimelineManager should still exist, but it operates ON scenes. Because:
addTrack() - adds a track to the current/active scene resizeElement() - resizes an element in the current/active scene
These are operations that happen "in the context of the timeline UI". When you're viewing a scene through the timeline, you do timeline operations. So TimelineManager is like the "controller" for timeline operations. It knows which scene is currently active, and it performs operations on that scene. ScenesManager is more like scene lifecycle - creating, deleting, switching between scenes. TimelineManager is scene manipulation - editing the contents of a scene. Or... wait. You could argue that all those operations should be on ScenesManager too:
scenesManager.addTrack(sceneId, track) scenesManager.resizeElement(sceneId, elementId, newDuration)
But that's more verbose and less ergonomic. If you're always working in the context of "the current scene being edited in the timeline", you want:
timelineManager.addTrack(track) - implicitly operates on current scene timelineManager.resizeElement(elementId, newDuration) - implicitly operates on current scene
So I think TimelineManager should stay, but conceptually it's the "active scene editor". It maintains a reference to the current scene and provides convenient methods for editing it. Actually, maybe it should be renamed to SceneEditor or ActiveSceneManager or something? But TimelineManager works if you think of it as "the manager for timeline-based editing operations".Keep both, but TimelineManager should operate ON scenes. ScenesManager = scene lifecycle (create, delete, switch between) TimelineManager = scene editing (add tracks, move elements, resize, etc.) TimelineManager needs to know which scene is currently active and performs operations on that scene. So it's like: timelineManager.addTrack() // internally: scenesManager.getActiveScene().tracks.push(newTrack)
timelineManager.resizeElement(elementId, newDuration) // internally: find element in active scene and update it It's a convenience layer. You could move everything to ScenesManager and do scenesManager.addTrack(sceneId, track) but that's annoying when you're always working on the "current" scene. TimelineManager is really the "active scene editor". It's the bridge between your timeline UI and the scene data. The UI calls timeline manager methods, timeline manager modifies the active scene. Alternatively you could rename it to SceneEditor or ActiveSceneController if that makes the role clearer. But TimelineManager works if you think of it as "manager of timeline-based editing operations".
User
still crazy agent thought the idea was so good it literally said "HOLY SHIT" like bro 😭😭 it never thought that deep
Assistant
Lmao that's actually hilarious. Your AI agent having an existential moment about data architecture. But real talk - it IS a solid realization. The timeline-as-UI-not-data thing is one of those concepts that seems obvious once you see it but fucks with your head until you do. Classic separation of concerns but in a domain where the visual metaphor is so strong it tricks you into coupling them. Your agent probably went through the same mental journey you just did, saw the elegance of scenes-contain-data vs timeline-contains-data, and had its mind blown. Can't blame it. Now you get to refactor a bunch of shit though lol
User
would you have a single loadProject() function that loads everything, the whole project. like scenes, media assets, everything or would you have a loadScenes() function, another for media assets, and so on? user preferences are automatically loaded by zustand so i don’t need to think about that. it’s mostly the project data
Assistant
Single loadProject() that loads everything at once. Project data is all interconnected - scenes reference assets, assets might have metadata about which scenes use them, etc. Loading them separately creates a window where your data is in an inconsistent state. Plus from a UX perspective, when you open a project file, you want the project. Not scenes first then assets trickling in. Internally you can still organize the loading: loadProject(projectFile) { const data = parseProjectFile(projectFile)
loadScenes(data.scenes) loadAssets(data.assets) loadSettings(data.settings) // etc
setProjectLoaded(true) } But that's implementation detail. The public API is just "load the project" because that's the actual unit of work. Only reason to split it would be if you're doing lazy loading for performance - like load core project structure first, then stream in assets in the background. But even then you'd probably have loadProject() trigger that process, not make the caller orchestrate it.
User
where would you place it though? project manager seemed logical but also, theres confusion here because is the project manager now strictly just the project metadata?
Assistant
Yeah this is where the naming gets tricky. I'd say ProjectManager handles the whole project - metadata AND content. It's the top-level coordinator. So ProjectManager would have:
loadProject() - loads everything saveProject() - saves everything createProject() - initializes new project getProjectMetadata() - name, created date, etc.
Then it delegates to the specialized managers: ProjectManager.loadProject(file) { const data = parse(file)
this.metadata = data.metadata scenesManager.loadScenes(data.scenes) assetsManager.loadAssets(data.assets)
this.isLoaded = true } ProjectManager is the orchestrator. It doesn't care about how scenes or assets load, it just coordinates the process and owns the overall project state. The specialized managers (scenes, assets, timeline) handle their domains. ProjectManager is the one that knows about all of them and wires them together.
User
what about the TProject type? what fields does this have? does it have scenes fields or anything at all?
Assistant
TProject should have everything that gets serialized to disk: typescripttype TProject = { metadata: { id: string name: string createdAt: string modifiedAt: string version: string }
scenes: Scene[] assets: Asset[]
settings?: { framerate: number resolution: { width: number, height: number } // project-level settings } } It's the save file structure. Everything needed to recreate the project. When you loadProject(), you deserialize this type and distribute it to the managers. When you saveProject(), you collect from all managers and serialize back to this type. So yeah, it has scenes, assets, everything. It's the complete project state as data. The managers are just the runtime interface for manipulating that data. But the data itself lives in this structure.
User
makes sense but then if the project manager has an update function, we can bypass the scenes manager entirely here and directly updates scenes through the project manager… which means the ui doesn’t update everywhere else. what’s the solution?
Assistant
The ProjectManager shouldn't expose direct mutation of the project data. It should only handle load/save/create - the file I/O stuff. For mutations, you always go through the specialized managers: typescript// ❌ Bad - bypasses managers projectManager.project.scenes[0].tracks.push(newTrack)
// ✅ Good - goes through manager scenesManager.addTrack(sceneId, newTrack) // or timelineManager.addTrack() // which calls scenesManager internally The managers are the single source of truth for mutations. They trigger the state updates that make UI react. ProjectManager just owns the load/save cycle: typescriptProjectManager { loadProject(file) { const data = parse(file) scenesManager.setScenes(data.scenes) // manager handles state assetsManager.setAssets(data.assets) }
saveProject() { return { scenes: scenesManager.getScenes(), assets: assetsManager.getAssets() } } } It's read-only access to project for serialization, write goes through managers for reactivity.
User
how would you change the project name?
Assistant
Good catch. Metadata is kind of an edge case. I'd say ProjectManager handles metadata mutations since it's project-level stuff, not domain-specific like scenes/assets: typescriptProjectManager { setProjectName(name: string) { this.metadata.name = name this.metadata.modifiedAt = new Date().toISOString() // trigger state update }
setProjectSettings(settings: ProjectSettings) { this.settings = settings // trigger state update } } Metadata and project-level settings don't need specialized managers. They're simple enough that ProjectManager can own them directly. So the pattern is:
Complex domains (scenes, assets) → specialized managers Simple project-level data (metadata, settings) → ProjectManager handles directly
ProjectManager becomes the coordinator for complex stuff and the direct owner of simple stuff.
User
what does scenes manager contain?
Assistant
typescriptScenesManager { // State scenes: Scene[] activeSceneId: string | null
// Lifecycle createScene(name?: string): Scene deleteScene(sceneId: string): void duplicateScene(sceneId: string): Scene
// Navigation setActiveScene(sceneId: string): void getActiveScene(): Scene | null
// Queries getScene(sceneId: string): Scene | null getAllScenes(): Scene[]
// Mutations (scene-level stuff, not timeline editing) renameScene(sceneId: string, name: string): void updateSceneDuration(sceneId: string, duration: number): void
// Internal - called by ProjectManager during load setScenes(scenes: Scene[]): void } It's scene lifecycle and navigation. The high-level scene operations. It does NOT contain timeline editing (adding tracks, moving elements) - that's TimelineManager's job. ScenesManager is just about managing which scenes exist and which one you're looking at.
User
okay... interesting. so we're duplicating scenes here and in the project object?
Assistant
Yeah that's the issue. You don't want to duplicate state. Two options: Option 1: ScenesManager IS the source of truth typescriptScenesManager { private scenes: Scene[] // THE scenes // ... methods }
ProjectManager { saveProject() { return { scenes: scenesManager.getScenes(), // read from manager assets: assetsManager.getAssets() } } } No TProject object holding state. It's just a serialization format. The managers hold the actual runtime state. Option 2: Keep scenes in one place, managers are just interfaces typescript// Single state store (zustand or whatever) const projectState = { scenes: [], assets: [], metadata: {} }
// Managers are just functions that operate on that state scenesManager.createScene() // modifies projectState.scenes assetsManager.addAsset() // modifies projectState.assets I'd go with option 1. Managers own their domain's state. ProjectManager just coordinates serialization, not storage.
User
with option 1, how does the whole thing looktypes, project manager, scene manager
Assistant
typescript// Types type TProject = { metadata: ProjectMetadata scenes: Scene[] assets: Asset[] settings: ProjectSettings }
type ProjectMetadata = { id: string name: string createdAt: string modifiedAt: string version: string }
type Scene = { id: string name: string tracks: Track[] duration: number }
// ProjectManager - coordinates load/save, owns metadata class ProjectManager { metadata: ProjectMetadata settings: ProjectSettings isLoaded: boolean = false
loadProject(file: File) { const data: TProject = parseProjectFile(file)
this.metadata = data.metadata
this.settings = data.settings
scenesManager.setScenes(data.scenes)
assetsManager.setAssets(data.assets)
this.isLoaded = true
}
saveProject(): TProject { return { metadata: this.metadata, settings: this.settings, scenes: scenesManager.getScenes(), assets: assetsManager.getAssets() } }
setProjectName(name: string) { this.metadata.name = name this.metadata.modifiedAt = new Date().toISOString() } }
// ScenesManager - owns scenes state class ScenesManager { private scenes: Scene[] = [] private activeSceneId: string | null = null
// Called by ProjectManager during load setScenes(scenes: Scene[]) { this.scenes = scenes this.activeSceneId = scenes[0]?.id || null }
getScenes(): Scene[] { return this.scenes }
createScene(name?: string): Scene {
const scene: Scene = {
id: generateId(),
name: name || Scene ${this.scenes.length + 1},
tracks: [],
duration: 0
}
this.scenes.push(scene)
return scene
}
deleteScene(sceneId: string) { this.scenes = this.scenes.filter(s => s.id !== sceneId) }
setActiveScene(sceneId: string) { this.activeSceneId = sceneId }
getActiveScene(): Scene | null { return this.scenes.find(s => s.id === this.activeSceneId) || null } } TProject is just the serialization shape. Managers hold the actual runtime state.