Serve the stage from a 1600px preview instead of the grid thumb.

Co-authored-by: Cursor <cursoragent@cursor.com>

server/utils/library.ts

@@ -1271,6 +1271,10 @@ export function stillThumbFile(owner: string, id: string) {
   return join(ownerRoot(owner), 'stills', `${id}.thumb.jpg`)
 }
 
+export function stillPreviewFile(owner: string, id: string) {
+  return join(ownerRoot(owner), 'stills', `${id}.preview.jpg`)
+}
+
 /** Sync check — never kicks ffmpeg. Empty string when thumb is missing or stale. */
 export function existingStillThumbPath(owner: string, id: string) {
   const source = stillPath(owner, id)
@@ -1282,14 +1286,27 @@ export function existingStillThumbPath(owner: string, id: string) {
   return ''
 }
 
+/** Sync check for stage preview — never kicks ffmpeg. */
+export function existingStillPreviewPath(owner: string, id: string) {
+  const source = stillPath(owner, id)
+  const dest = stillPreviewFile(owner, id)
+  if (!existsSync(source) || !existsSync(dest)) return ''
+  try {
+    if (statSync(dest).mtimeMs >= statSync(source).mtimeMs) return dest
+  } catch { return '' }
+  return ''
+}
+
 function removeStillFiles(owner: string, id: string) {
   rmSync(stillPath(owner, id), { force: true })
   rmSync(stillThumbFile(owner, id), { force: true })
+  rmSync(stillPreviewFile(owner, id), { force: true })
 }
 
 let thumbSlots = 0
 const thumbWaiters: Array<() => void> = []
 const thumbBuilds = new Map<string, Promise<string>>()
+const previewBuilds = new Map<string, Promise<string>>()
 
 function withThumbSlot<T>(fn: () => Promise<T>) {
   return new Promise<T>((resolve, reject) => {
@@ -1306,14 +1323,14 @@ function withThumbSlot<T>(fn: () => Promise<T>) {
   })
 }
 
-function buildStillThumb(source: string, dest: string) {
+function buildStillJpeg(source: string, dest: string, scale: string, quality: string) {
   return new Promise<boolean>((resolve) => {
     const proc = spawn('ffmpeg', [
       '-y',
       '-i', source,
-      '-vf', 'scale=384:-2',
+      '-vf', scale,
       '-frames:v', '1',
-      '-q:v', '5',
+      '-q:v', quality,
       dest
     ], { stdio: 'ignore' })
     const timer = setTimeout(() => {
@@ -1331,6 +1348,14 @@ function buildStillThumb(source: string, dest: string) {
   })
 }
 
+function buildStillThumb(source: string, dest: string) {
+  return buildStillJpeg(source, dest, 'scale=384:-2', '5')
+}
+
+function buildStillPreview(source: string, dest: string) {
+  return buildStillJpeg(source, dest, 'scale=1600:-2', '3')
+}
+
 export async function stillThumbPath(owner: string, id: string) {
   const source = stillPath(owner, id)
   const dest = stillThumbFile(owner, id)
@@ -1340,7 +1365,7 @@ export async function stillThumbPath(owner: string, id: string) {
       if (statSync(dest).mtimeMs >= statSync(source).mtimeMs) return dest
     } catch { /* rebuild */ }
   }
-  const key = `${owner}:${id}`
+  const key = `${owner}:${id}:thumb`
   const pending = thumbBuilds.get(key)
   if (pending) return pending
   const build = withThumbSlot(async () => {
@@ -1354,6 +1379,29 @@ export async function stillThumbPath(owner: string, id: string) {
   return build
 }
 
+export async function stillPreviewPath(owner: string, id: string) {
+  const source = stillPath(owner, id)
+  const dest = stillPreviewFile(owner, id)
+  if (!existsSync(source)) return ''
+  if (existsSync(dest)) {
+    try {
+      if (statSync(dest).mtimeMs >= statSync(source).mtimeMs) return dest
+    } catch { /* rebuild */ }
+  }
+  const key = `${owner}:${id}:preview`
+  const pending = previewBuilds.get(key)
+  if (pending) return pending
+  const build = withThumbSlot(async () => {
+    const ok = await buildStillPreview(source, dest)
+    // Never return the archive master as a stage preview
+    return ok ? dest : ''
+  }).finally(() => {
+    previewBuilds.delete(key)
+  })
+  previewBuilds.set(key, build)
+  return build
+}
+
 export async function ensureStillThumbnails(owner: string, opts?: { limit?: number }) {
   const catalog = readCatalog(owner)
   const cap = Math.max(0, Math.min(Number(opts?.limit) || 2, 8))
@@ -1603,6 +1651,7 @@ export async function saveStill(params: {
     next.stills.unshift(still)
   })
   void stillThumbPath(params.ownerKey, still.id).catch(() => null)
+  void stillPreviewPath(params.ownerKey, still.id).catch(() => null)
   return still
 }