Use the parent clip last frame and new-segment join for extensions, not the stitched file's first frame. Show this account's library storage in Settings.

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

server/utils/library.ts

@@ -5,7 +5,7 @@ import { spawn } from 'node:child_process'
 import { randomBytes, scrypt, timingSafeEqual } from 'node:crypto'
 import { promisify } from 'node:util'
 import type { H3Event } from 'h3'
-import { extractFirstFrame, extractLastFrame, remuxFaststart } from '~/server/utils/ffmpeg'
+import { extractFirstFrame, extractFrameAt, extractLastFrame, probeDuration, remuxFaststart } from '~/server/utils/ffmpeg'
 import { normalizePermanenceRefs, type PermanenceRef } from '~/utils/globalLocks'
 
 const scryptAsync = promisify(scrypt)
@@ -122,7 +122,7 @@ interface Catalog {
 
 const writeChains = new Map<string, Promise<unknown>>()
 
-function libraryRoot() {
+export function libraryRoot() {
   const config = useRuntimeConfig()
   return (config.libraryDir || process.env.LIBRARY_DIR || '/data/library').replace(/\/$/, '')
 }
@@ -137,7 +137,7 @@ export function libraryOwnerKey(event: H3Event) {
   return createHash('sha256').update(raw).digest('hex').slice(0, 24)
 }
 
-function ownerRoot(owner: string) {
+export function ownerRoot(owner: string) {
   return join(libraryRoot(), 'users', owner)
 }
 
@@ -612,11 +612,69 @@ export async function ensureScaledThumb(source: string, dest: string) {
   return build
 }
 
+type FrameSourceMeta = {
+  videoMtime: number
+  videoSize: number
+  mode: 'file-start' | 'segment-start' | 'last'
+  seek?: number
+}
+
+function frameMetaPath(dest: string) {
+  return `${dest}.src.json`
+}
+
+function readFrameMeta(dest: string): FrameSourceMeta | null {
+  try {
+    const raw = JSON.parse(readFileSync(frameMetaPath(dest), 'utf8')) as FrameSourceMeta
+    if (!raw || typeof raw.videoMtime !== 'number' || typeof raw.videoSize !== 'number') return null
+    return raw
+  } catch {
+    return null
+  }
+}
+
+function writeFrameMeta(dest: string, video: string, mode: FrameSourceMeta['mode'], seek?: number) {
+  try {
+    const info = statSync(video)
+    const meta: FrameSourceMeta = { videoMtime: info.mtimeMs, videoSize: info.size, mode }
+    if (typeof seek === 'number') meta.seek = seek
+    writeFileSync(frameMetaPath(dest), JSON.stringify(meta))
+  } catch { /* thumbs still work without the sidecar */ }
+}
+
+function frameCacheFresh(video: string, dest: string, mode: FrameSourceMeta['mode']) {
+  if (!existsSync(dest) || statSync(dest).size < 64) return false
+  try {
+    const info = statSync(video)
+    const meta = readFrameMeta(dest)
+    if (meta) {
+      return meta.mode === mode && meta.videoMtime === info.mtimeMs && meta.videoSize === info.size
+    }
+    return statSync(dest).mtimeMs >= info.mtimeMs && mode === 'file-start'
+  } catch {
+    return false
+  }
+}
+
+async function parentVideoDuration(owner: string, parentId?: string) {
+  if (!parentId) return 0
+  const video = clipVideoPath(owner, parentId)
+  if (!existsSync(video)) return 0
+  try {
+    return await probeDuration(video)
+  } catch {
+    return 0
+  }
+}
+
 export async function ensureClipLastFrame(owner: string, id: string) {
   const video = clipVideoPath(owner, id)
   const dest = clipLastFramePath(owner, id)
   if (!existsSync(video)) return ''
-  if (!existsSync(dest)) await extractLastFrame(video, dest)
+  if (!frameCacheFresh(video, dest, 'last')) {
+    await extractLastFrame(video, dest)
+    writeFrameMeta(dest, video, 'last')
+  }
   return existsSync(dest) ? dest : ''
 }
 
@@ -624,8 +682,29 @@ export async function ensureClipFirstFrame(owner: string, id: string) {
   const video = clipVideoPath(owner, id)
   const dest = clipFirstFramePath(owner, id)
   if (!existsSync(video)) return ''
-  if (!existsSync(dest)) await extractFirstFrame(video, dest)
-  return existsSync(dest) ? dest : ''
+  const catalog = readCatalog(owner)
+  const clip = catalog.clips.find(item => item.id === id)
+  const parentDur = await parentVideoDuration(owner, clip?.parentClipId)
+  let fileDur = 0
+  try {
+    fileDur = await probeDuration(video)
+  } catch { /* treat as a single segment */ }
+  const stored = Number(clip?.duration) || 0
+  const stitched = (parentDur > 0.5 && fileDur > parentDur + 0.4)
+    || (stored > 0.5 && fileDur > stored + 0.8)
+  const seek = parentDur > 0.5 && fileDur > parentDur + 0.4
+    ? parentDur
+    : (stitched && stored > 0.5 ? Math.max(0, fileDur - stored) : 0)
+  const mode: FrameSourceMeta['mode'] = stitched ? 'segment-start' : 'file-start'
+  if (frameCacheFresh(video, dest, mode)) return dest
+  if (stitched) {
+    await extractFrameAt(video, dest, seek)
+    writeFrameMeta(dest, video, 'segment-start', seek)
+    return dest
+  }
+  await extractFirstFrame(video, dest)
+  writeFrameMeta(dest, video, 'file-start', 0)
+  return dest
 }
 
 export function extendTempDir(owner: string, jobId: string) {
@@ -1313,6 +1392,7 @@ export async function saveClip(params: {
   sound?: boolean
   globalLocks?: string
   permanenceRefs?: PermanenceRef[]
+  segmentFirstFrame?: Buffer
 }) {
   const catalog = readCatalog(params.ownerKey)
   const folder = catalog.folders.find(item => item.id === params.folderId) || catalog.folders[0]
@@ -1349,6 +1429,11 @@ export async function saveClip(params: {
   const videoPath = clipVideoPath(params.ownerKey, clip.id)
   writeFileSync(videoPath, params.video)
   await remuxFaststart(videoPath)
+  if (params.segmentFirstFrame?.length && params.segmentFirstFrame.length >= 64) {
+    const firstPath = clipFirstFramePath(params.ownerKey, clip.id)
+    writeFileSync(firstPath, params.segmentFirstFrame)
+    writeFrameMeta(firstPath, videoPath, 'segment-start')
+  }
   if (typeof params.duration === 'number' && params.duration > 0) {
     clip.duration = params.duration
   } else {