feat(admin): auto-fill new scene length from the AEP

When adding a scene in the admin scene editor, its duration is now pulled
from the After Effects project automatically (scene key = comp name).

frontend (ProjectScenes):
- the new/edit scene form quick-scans the project .aep for comp names +
  durations and offers a "pick composition" dropdown that fills key, title
  and default duration in one click
- the key field gains a datalist of comp names; typing a key that matches a
  comp auto-fills the length (only when empty, never clobbering a manual value)
- an inline "AEP duration: Ns — insert" hint next to the duration field
- graceful states when no .aep is uploaded / scan fails

render-svc (aep.durationFromCdta): fix the composition-duration offset.
The duration rational lives at cdta offset 44 (numerator) / 48 (time base)
on AE 2024/2026, not 32/36 (previous guess) or 40/44 (boltframe reference,
older builds). Made it version-robust: read the time base from the framerate
dividend (offsets 4/8) and accept whichever offset places the time base right
after the numerator. Verified against a real project — render comp frfinal
parses to 15.02s (matches project_duration_sec 15.00).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

services/render/internal/aep/parse.go

@@ -181,27 +181,44 @@ func clean(b []byte) string {
 	return strings.TrimSpace(strings.TrimRight(string(b), "\x00"))
 }
 
-// durationFromCdta makes a best-effort attempt to read the comp duration from the
-// cdta chunk. The cdta layout varies by AE version; we read the frame-duration /
-// time-scale pair at well-known offsets and fall back to 0 (unknown) on any doubt.
-// Returning 0 is safe — the importer treats it as "leave duration unset".
+// durationFromCdta reads the comp duration (in seconds) from the cdta chunk.
+//
+// cdta layout (verified empirically against AE 2024/2026 project files):
+//
+//	off  4  u32  framerate divisor
+//	off  8  u32  framerate dividend == comp time base (ticks/sec)
+//	off 44  u32  duration numerator (in time-base ticks)
+//	off 48  u32  duration divisor   (== time base)
+//
+// duration_seconds = numerator / time_base. The duration's byte offset shifts by
+// AE version (44 on recent builds, 40 on older ones documented by the boltframe
+// reference parser), so rather than hard-code one offset we accept whichever
+// places the time base immediately *after* the numerator — that self-selects the
+// correct field and rejects garbage. Returns 0 (unknown) on any doubt; the
+// importer treats 0 as "leave duration unset".
 func durationFromCdta(cdta []byte) float64 {
-	// cdta encodes time as rational values. Two uint32 BE commonly hold the comp
-	// duration (in frames at the comp's time scale) and the time scale (fps base).
-	// Offsets 0x20 (duration) and 0x24 (scale) are the most consistent across
-	// recent versions; guard heavily and bail to 0 if the numbers look invalid.
-	if len(cdta) < 0x28 {
+	if len(cdta) < 52 {
 		return 0
 	}
-	durFrames := binary.BigEndian.Uint32(cdta[0x20:0x24])
-	scale := binary.BigEndian.Uint32(cdta[0x24:0x28])
-	if scale == 0 || durFrames == 0 || scale > 100000 || durFrames > 100000000 {
+	frDivisor := binary.BigEndian.Uint32(cdta[4:8])
+	timeBase := binary.BigEndian.Uint32(cdta[8:12]) // framerate dividend
+	if frDivisor == 0 || timeBase == 0 {
 		return 0
 	}
-	sec := float64(durFrames) / float64(scale)
-	if sec <= 0 || sec > 36000 { // > 10h is nonsense → treat as unknown
-		return 0
+	if fps := float64(timeBase) / float64(frDivisor); fps < 1 || fps > 240 {
+		return 0 // not a comp cdta we recognise
 	}
-	// round to 2 dp
-	return float64(int(sec*100+0.5)) / 100
+	for _, off := range []int{44, 40} { // recent layout first, then older
+		num := binary.BigEndian.Uint32(cdta[off : off+4])
+		div := binary.BigEndian.Uint32(cdta[off+4 : off+8])
+		if num == 0 || div != timeBase {
+			continue // divisor must equal the time base to be the duration field
+		}
+		sec := float64(num) / float64(timeBase)
+		if sec <= 0 || sec > 36000 { // > 10h is nonsense
+			continue
+		}
+		return float64(int(sec*100+0.5)) / 100 // round to 2 dp
+	}
+	return 0
 }

src/components/admin/ProjectScenes.tsx

@@ -27,6 +27,9 @@ interface SharedColor {
 }
 interface PresetItem { id?: string; element_key: string; value: string; sort: number }
 interface Preset { id: string; project_id: string; name?: string | null; sort: number; items: PresetItem[] }
+// A composition discovered in the project's .aep (quick scan): name + duration.
+interface AepComp { key: string; title: string; default_duration_sec: number | null }
+type CompsState = "idle" | "loading" | "loaded" | "none" | "error";
 
 const SCENE_TYPES = [
   { v: "Normal", l: "معمولی" },
@@ -102,6 +105,10 @@ function ScenesTab({ projectId, fixedScenes }: { projectId: string; fixedScenes?
   const [err, setErr] = useState<string | null>(null);
   const [scanOpen, setScanOpen] = useState(false);
   const [inputsFor, setInputsFor] = useState<string | null>(null);
+  // AEP compositions (key + duration) read from the uploaded .aep — used to
+  // auto-fill a new scene's length from After Effects.
+  const [aepComps, setAepComps] = useState<AepComp[]>([]);
+  const [compsState, setCompsState] = useState<CompsState>("idle");
   const base = "/api/admin/resource/scenes";
 
   const load = useCallback(async () => {
@@ -112,6 +119,31 @@ function ScenesTab({ projectId, fixedScenes }: { projectId: string; fixedScenes?
   }, [projectId]);
   useEffect(() => { load(); }, [load]);
 
+  // Quick-scan the project's .aep (headless Go parser) for comp names + durations.
+  const loadComps = useCallback(async () => {
+    setCompsState("loading");
+    try {
+      const r = await fetch(`/api/admin/resource/template-scans/${projectId}/quick`, {
+        method: "POST", headers: { "Content-Type": "application/json" }, body: "{}",
+      });
+      if (!r.ok) { setAepComps([]); setCompsState("none"); return; }
+      const d = await r.json().catch(() => null);
+      const scenes: unknown[] = Array.isArray(d?.scenes) ? d.scenes : [];
+      const comps: AepComp[] = scenes
+        .map((s) => s as Record<string, unknown>)
+        .filter((s) => typeof s.key === "string" && s.key)
+        .map((s) => ({
+          key: String(s.key),
+          title: typeof s.title === "string" && s.title ? String(s.title) : String(s.key),
+          default_duration_sec: typeof s.default_duration_sec === "number" ? s.default_duration_sec : null,
+        }));
+      setAepComps(comps);
+      setCompsState(comps.length ? "loaded" : "none");
+    } catch {
+      setAepComps([]); setCompsState("error");
+    }
+  }, [projectId]);
+
   const save = async () => {
     if (!draft) return;
     if (!draft.key.trim() || !draft.title.trim()) { setErr("کلید و عنوان صحنه الزامی است"); return; }
@@ -147,6 +179,7 @@ function ScenesTab({ projectId, fixedScenes }: { projectId: string; fixedScenes?
         draft={draft} setDraft={setDraft} saving={saving} err={err}
         onCancel={() => { setDraft(null); setEditId(null); setErr(null); }}
         onSave={save} isEdit={!!editId}
+        aepComps={aepComps} compsState={compsState} onLoadComps={loadComps}
       />
     );
   }
@@ -160,7 +193,7 @@ function ScenesTab({ projectId, fixedScenes }: { projectId: string; fixedScenes?
           {fixedScenes ? (
             <span className="rounded-lg border border-[#262b40] px-3 py-2 text-xs text-gray-500">صحنه‌ها از روی پروژهٔ افترافکت تعریف می‌شوند (پروژهٔ Fix)</span>
           ) : (
-            <button className={btn} onClick={() => { setEditId(null); setDraft(emptyDraft(rows.length)); }}>+ صحنهٔ جدید</button>
+            <button className={btn} onClick={() => { setEditId(null); setDraft(emptyDraft(rows.length)); if (compsState === "idle") loadComps(); }}>+ صحنهٔ جدید</button>
           )}
         </div>
       </div>
@@ -192,7 +225,7 @@ function ScenesTab({ projectId, fixedScenes }: { projectId: string; fixedScenes?
                   >
                     ورودی‌ها
                   </button>
-                  <button className={ghost} onClick={() => { setEditId(s.id); setDraft(sceneToDraft(s)); }}>ویرایش</button>
+                  <button className={ghost} onClick={() => { setEditId(s.id); setDraft(sceneToDraft(s)); if (compsState === "idle") loadComps(); }}>ویرایش</button>
                   <button className={del} onClick={() => remove(s)}>حذف</button>
                 </div>
               </div>
@@ -212,11 +245,44 @@ function ScenesTab({ projectId, fixedScenes }: { projectId: string; fixedScenes?
 function num(v: number | null | undefined) { return v === null || v === undefined ? "" : String(v); }
 function toNum(v: string): number | null { return v.trim() === "" ? null : Number(v); }
 
-function SceneForm({ draft, setDraft, onSave, onCancel, saving, err, isEdit }: {
+function SceneForm({ draft, setDraft, onSave, onCancel, saving, err, isEdit, aepComps, compsState, onLoadComps }: {
   draft: SceneDraft; setDraft: (d: SceneDraft) => void; onSave: () => void; onCancel: () => void;
   saving: boolean; err: string | null; isEdit: boolean;
+  aepComps: AepComp[]; compsState: CompsState; onLoadComps: () => void;
 }) {
   const set = (p: Partial<SceneDraft>) => setDraft({ ...draft, ...p });
+
+  // Typing the key: if it exactly matches an AEP comp, auto-fill the length
+  // (only when the duration is still empty, so a manual value is never clobbered)
+  // and the title when blank.
+  const onKeyChange = (k: string) => {
+    const c = aepComps.find((x) => x.key.toLowerCase() === k.trim().toLowerCase());
+    if (!isEdit && c) {
+      set({
+        key: k,
+        title: draft.title.trim() ? draft.title : c.title,
+        default_duration_sec: draft.default_duration_sec == null ? c.default_duration_sec : draft.default_duration_sec,
+      });
+    } else {
+      set({ key: k });
+    }
+  };
+
+  // Explicit pick from the comp dropdown: always fill key/title/length from AEP.
+  const pickComp = (key: string) => {
+    const c = aepComps.find((x) => x.key === key);
+    if (!c) return;
+    set({
+      key: c.key,
+      title: draft.title.trim() ? draft.title : c.title,
+      default_duration_sec: c.default_duration_sec ?? draft.default_duration_sec,
+      max_duration_sec: draft.max_duration_sec ?? c.default_duration_sec ?? null,
+    });
+  };
+
+  // The AEP comp whose name matches the current key (for the inline duration hint).
+  const matched = aepComps.find((x) => x.key.trim().toLowerCase() === draft.key.trim().toLowerCase()) ?? null;
+
   return (
     <div className="space-y-4">
       <div className="flex items-center justify-between">
@@ -225,8 +291,42 @@ function SceneForm({ draft, setDraft, onSave, onCancel, saving, err, isEdit }: {
       </div>
       {err && <p className="rounded-lg bg-red-500/10 px-3 py-2 text-sm text-red-300">{err}</p>}
 
+      {!isEdit && (
+        <div className="space-y-2 rounded-lg border border-indigo-500/30 bg-indigo-500/5 p-3">
+          <div className="flex items-center justify-between gap-2">
+            <label className="text-xs font-medium text-indigo-200">پر کردن خودکار از کامپوزیشن افترافکت</label>
+            <button type="button" className={ghost} onClick={onLoadComps} disabled={compsState === "loading"}>
+              {compsState === "loading" ? "در حال خواندن AEP…" : "↻ خواندن از AEP"}
+            </button>
+          </div>
+          {compsState === "loaded" && aepComps.length > 0 ? (
+            <select className={`${inp} w-full`} value="" onChange={(e) => pickComp(e.target.value)}>
+              <option value="">— انتخاب کامپوزیشن (کلید، عنوان و مدت پر می‌شود) —</option>
+              {aepComps.map((c) => (
+                <option key={c.key} value={c.key}>
+                  {c.title}{c.default_duration_sec != null ? ` — ${c.default_duration_sec} ثانیه` : " — مدت نامشخص"}
+                </option>
+              ))}
+            </select>
+          ) : compsState === "loading" ? (
+            <p className="text-[11px] text-gray-400">در حال خواندن کامپوزیشن‌ها از فایل AEP…</p>
+          ) : compsState === "none" ? (
+            <p className="text-[11px] text-amber-300/80">کامپوزیشنی خوانده نشد. برای پر شدن خودکار مدت، ابتدا فایل AEP پروژه را از بخش «فایل‌ها» آپلود کنید.</p>
+          ) : compsState === "error" ? (
+            <p className="text-[11px] text-red-300/80">خطا در خواندن فایل AEP.</p>
+          ) : (
+            <p className="text-[11px] text-gray-500">در حال آماده‌سازی…</p>
+          )}
+          <p className="text-[10px] text-gray-500">کلید صحنه با نام کامپوزیشن یکی است؛ هنگام تایپ کلید نیز مدت به‌صورت خودکار از AEP پر می‌شود.</p>
+        </div>
+      )}
+
       <div className="grid gap-3 sm:grid-cols-2">
-        <div><label className={lbl}>کلید (نام کامپوزیشن AE) *</label><input className={`${inp} w-full`} dir="ltr" value={draft.key} onChange={(e) => set({ key: e.target.value })} placeholder="scene_intro" /></div>
+        <div>
+          <label className={lbl}>کلید (نام کامپوزیشن AE) *</label>
+          <input className={`${inp} w-full`} dir="ltr" list="aep-comp-names" value={draft.key} onChange={(e) => onKeyChange(e.target.value)} placeholder="scene_intro" />
+          <datalist id="aep-comp-names">{aepComps.map((c) => <option key={c.key} value={c.key} />)}</datalist>
+        </div>
         <div><label className={lbl}>عنوان *</label><input className={`${inp} w-full`} value={draft.title} onChange={(e) => set({ title: e.target.value })} /></div>
         <div><label className={lbl}>عنوان (فارسی)</label><input className={`${inp} w-full`} value={draft._fa} onChange={(e) => set({ _fa: e.target.value })} /></div>
         <div><label className={lbl}>عنوان (انگلیسی)</label><input className={`${inp} w-full`} dir="ltr" value={draft._en} onChange={(e) => set({ _en: e.target.value })} /></div>
@@ -238,7 +338,15 @@ function SceneForm({ draft, setDraft, onSave, onCancel, saving, err, isEdit }: {
         </div>
         <div><label className={lbl}>ترتیب</label><input className={`${inp} w-full`} type="number" dir="ltr" value={num(draft.sort)} onChange={(e) => set({ sort: Number(e.target.value) || 0 })} /></div>
 
-        <div><label className={lbl}>مدت پیش‌فرض (ثانیه)</label><input className={`${inp} w-full`} type="number" step="0.1" dir="ltr" value={num(draft.default_duration_sec)} onChange={(e) => set({ default_duration_sec: toNum(e.target.value) })} /></div>
+        <div>
+          <label className={lbl}>مدت پیش‌فرض (ثانیه)</label>
+          <input className={`${inp} w-full`} type="number" step="0.1" dir="ltr" value={num(draft.default_duration_sec)} onChange={(e) => set({ default_duration_sec: toNum(e.target.value) })} />
+          {matched && matched.default_duration_sec != null && matched.default_duration_sec !== draft.default_duration_sec && (
+            <button type="button" className="mt-1 text-[11px] text-indigo-300 hover:underline" onClick={() => set({ default_duration_sec: matched.default_duration_sec })}>
+              مدت در AEP: {matched.default_duration_sec} ثانیه — درج
+            </button>
+          )}
+        </div>
         <div><label className={lbl}>هم‌پوشانی پایان (ثانیه)</label><input className={`${inp} w-full`} type="number" step="0.1" dir="ltr" value={num(draft.overlap_at_end_sec)} onChange={(e) => set({ overlap_at_end_sec: Number(e.target.value) || 0 })} /></div>
         <div><label className={lbl}>حداقل مدت (ثانیه)</label><input className={`${inp} w-full`} type="number" step="0.1" dir="ltr" value={num(draft.min_duration_sec)} onChange={(e) => set({ min_duration_sec: toNum(e.target.value) })} /></div>
         <div><label className={lbl}>حداکثر مدت (ثانیه)</label><input className={`${inp} w-full`} type="number" step="0.1" dir="ltr" value={num(draft.max_duration_sec)} onChange={(e) => set({ max_duration_sec: toNum(e.target.value) })} /></div>