feat: 缩略图优先从本地视频抽帧生成,远程图为回退

DEPLOY.md

@@ -27,8 +27,8 @@ default, e.g. via QEMU emulation).
 
 ```sh
 docker buildx build --platform linux/amd64 \
-  --build-arg VERSION=1.16 \
-  -t 192.168.2.212:3000/tigeren/metube:1.16 \
+  --build-arg VERSION=1.17 \
+  -t 192.168.2.212:3000/tigeren/metube:1.17 \
   --push .
 ```
 

app/main.py

@@ -357,39 +357,100 @@ def sniff_image_type(data: bytes) -> str:
     return 'application/octet-stream'
 
 
+def _placeholder_thumb_response():
+    return web.Response(text=PLACEHOLDER_THUMB, content_type='image/svg+xml', headers={'Cache-Control': 'public, max-age=3600'})
+
+
+async def _probe_duration(video_path):
+    """Duration of a local media file in seconds via ffprobe, or None."""
+    cmd = ['ffprobe', '-v', 'error', '-show_entries', 'format=duration',
+           '-of', 'csv=p=0', video_path]
+    try:
+        proc = await asyncio.create_subprocess_exec(
+            *cmd, stdout=asyncio.subprocess.PIPE, stderr=asyncio.subprocess.DEVNULL)
+        out, _ = await asyncio.wait_for(proc.communicate(), timeout=15)
+        return float(out.decode().strip())
+    except Exception:  # noqa: BLE001 - probing is best-effort
+        return None
+
+
+async def _extract_video_frame(video_path, thumb_path, duration):
+    """Extract a frame from a local video file with ffmpeg. Returns True on success."""
+    if not duration:
+        duration = await _probe_duration(video_path)
+    seek = 1.0
+    if duration:
+        try:
+            duration = float(duration)
+            seek = max(0.0, min(duration * 0.25, duration - 1.0))
+        except (TypeError, ValueError):
+            pass
+    cmd = ['ffmpeg', '-hide_banner', '-loglevel', 'error',
+           '-ss', str(seek), '-i', video_path,
+           '-frames:v', '1', '-vf', 'scale=480:-2', '-q:v', '4',
+           # thumb_path has a generic .img extension: force the JPEG encoder and
+           # image2 muxer explicitly (ffmpeg would otherwise guess from the name)
+           '-c:v', 'mjpeg', '-f', 'image2',
+           '-y', thumb_path]
+    try:
+        proc = await asyncio.create_subprocess_exec(
+            *cmd, stdout=asyncio.subprocess.DEVNULL, stderr=asyncio.subprocess.PIPE)
+        _, err = await asyncio.wait_for(proc.communicate(), timeout=30)
+    except Exception as exc:  # noqa: BLE001 - includes TimeoutError; fall through to other sources
+        log.warning(f"ffmpeg frame extraction failed for {video_path}: {exc}")
+        try:
+            proc.kill()
+        except Exception:  # noqa: BLE001 - process may not exist
+            pass
+        return False
+    if proc.returncode != 0:
+        log.warning(f"ffmpeg frame extraction failed for {video_path}: {err.decode(errors='replace')[-200:]}")
+        return False
+    return os.path.exists(thumb_path)
+
+
 @routes.get(config.URL_PREFIX + 'thumbnail')
 async def thumbnail(request):
-    """Serve a cached copy of a download's remote thumbnail.
+    """Serve a cached thumbnail for a download.
 
-    The URL is taken from stored yt-dlp metadata for the given download key —
-    clients can never point this endpoint at arbitrary URLs. Missing/invalid
-    thumbnails fall back to a placeholder SVG.
+    Sources, in order: a frame extracted from the local file (ffmpeg), the
+    remote thumbnail URL from stored yt-dlp metadata — clients can never point
+    this endpoint at arbitrary URLs — and finally a placeholder SVG.
     """
     key = request.query.get('id')
     if not key:
         raise web.HTTPBadRequest()
 
     info = dqueue.find_info(key)
-    if info is None or not info.thumbnail:
-        return web.Response(text=PLACEHOLDER_THUMB, content_type='image/svg+xml', headers={'Cache-Control': 'public, max-age=3600'})
+    thumb_url = getattr(info, 'thumbnail', None) if info is not None else None
+    log.debug(f"[Thumb] key={key[:60]} found={info is not None} has_url={bool(thumb_url)}")
 
     thumb_dir = os.path.join(config.STATE_DIR, 'thumbnails')
     os.makedirs(thumb_dir, exist_ok=True)
     thumb_path = os.path.join(thumb_dir, hashlib.sha1(key.encode('utf-8')).hexdigest() + '.img')
 
     if not os.path.exists(thumb_path):
-        try:
-            timeout = aiohttp.ClientTimeout(total=15)
-            async with aiohttp.ClientSession(timeout=timeout) as session:
-                async with session.get(info.thumbnail, headers={'User-Agent': 'Mozilla/5.0 MeTube'}) as resp:
-                    if resp.status != 200:
-                        return web.Response(text=PLACEHOLDER_THUMB, content_type='image/svg+xml', headers={'Cache-Control': 'public, max-age=3600'})
-                    data = await resp.read()
-            with open(thumb_path, 'wb') as f:
-                f.write(data)
-        except Exception as exc:  # noqa: BLE001 - fall back to placeholder on any fetch error
-            log.warning(f"Failed to fetch thumbnail for {key}: {exc}")
-            return web.Response(text=PLACEHOLDER_THUMB, content_type='image/svg+xml', headers={'Cache-Control': 'public, max-age=3600'})
+        # Prefer a frame from the local file: works even for downloads whose
+        # metadata predates thumbnail storage, and survives expiring remote URLs
+        local_file = dqueue.find_download_file(key)
+        log.debug(f"[Thumb] local_file={local_file}")
+        if local_file:
+            await _extract_video_frame(local_file, thumb_path, getattr(info, 'duration', None))
+
+        if not os.path.exists(thumb_path) and thumb_url:
+            try:
+                timeout = aiohttp.ClientTimeout(total=15)
+                async with aiohttp.ClientSession(timeout=timeout) as session:
+                    async with session.get(thumb_url, headers={'User-Agent': 'Mozilla/5.0 MeTube'}) as resp:
+                        if resp.status == 200:
+                            data = await resp.read()
+                            with open(thumb_path, 'wb') as f:
+                                f.write(data)
+            except Exception as exc:  # noqa: BLE001 - fall back to placeholder on any fetch error
+                log.warning(f"Failed to fetch thumbnail for {key}: {exc}")
+
+        if not os.path.exists(thumb_path):
+            return _placeholder_thumb_response()
 
     with open(thumb_path, 'rb') as f:
         data = f.read()

app/ytdl.py

@@ -326,6 +326,11 @@ class PersistentQueue:
             # Ensure file_exists field exists
             if not hasattr(v, 'file_exists'):
                 v.file_exists = None
+            # Ensure thumbnail/duration fields exist (added for the thumbnail UI)
+            if not hasattr(v, 'thumbnail'):
+                v.thumbnail = None
+            if not hasattr(v, 'duration'):
+                v.duration = None
             self.dict[k] = Download(None, None, None, None, None, None, {}, v)
 
     def exists(self, key):
@@ -396,6 +401,20 @@ class DownloadQueue:
                     return v
         return None
 
+    def find_download_file(self, key):
+        """Absolute path of the downloaded file for key, if it exists on disk."""
+        info = self.find_info(key)
+        if info is None:
+            return None
+        filename = getattr(info, 'filename', None)
+        if not filename:
+            return None
+        dldirectory, error = self.__calc_download_path(info.quality, info.format, getattr(info, 'folder', None))
+        if error is not None or not dldirectory:
+            return None
+        path = os.path.join(dldirectory, filename)
+        return path if os.path.exists(path) else None
+
     async def __import_queue(self):
         for k, v in self.queue.saved_items():
             await self.__add_download(v, True)
@@ -475,6 +494,12 @@ class DownloadQueue:
                     if full_entry and 'title' in full_entry:
                         title = full_entry['title']
                         log.debug(f"[PreCheck] Got real title from full extraction: '{title}'")
+                        # Backfill thumbnail/duration for flat playlist entries
+                        if not getattr(dl, 'thumbnail', None):
+                            thumbnails = full_entry.get('thumbnails') or []
+                            dl.thumbnail = full_entry.get('thumbnail') or (thumbnails[-1].get('url') if thumbnails else None)
+                        if not getattr(dl, 'duration', None):
+                            dl.duration = full_entry.get('duration')
                 except Exception as e:
                     log.warning(f"[PreCheck] Failed to get full info: {e}, using placeholder title")
             

ui/src/app/download-card.component.html

@@ -1,10 +1,7 @@
 <div class="card" [class.selected]="selected">
   <input type="checkbox" class="card-check" [checked]="selected" (change)="selectChange.emit($event.target.checked)" [attr.aria-label]="'选择 ' + row.value.title">
   <div class="thumb">
-    <img *ngIf="row.value.thumbnail" [src]="thumbUrl()" [alt]="row.value.title" loading="lazy">
-    <span class="thumb-ph" *ngIf="!row.value.thumbnail">
-      <svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round"><rect x="2" y="4" width="20" height="16" rx="2"/><polyline points="10 9 15 12 10 15"/></svg>
-    </span>
+    <img [src]="thumbUrl()" [alt]="row.value.title" loading="lazy">
     <span class="dur num" *ngIf="row.value.duration">{{ row.value.duration | duration }}</span>
     <span *ngIf="row.value.file_exists === false" class="file-warn" title="文件不存在">
       <fa-icon [icon]="faTimesCircle"></fa-icon>

ui/src/app/download-row.component.html

@@ -1,8 +1,8 @@
 <div class="q-row" [class.selected]="selected">
   <input type="checkbox" class="q-check" [checked]="selected" (change)="selectChange.emit($event.target.checked)" [attr.aria-label]="'选择 ' + row.value.title">
   <div class="thumb">
-    <img *ngIf="row.value.thumbnail" [src]="thumbUrl()" [alt]="row.value.title" loading="lazy">
-    <span class="thumb-ph" *ngIf="!row.value.thumbnail">
+    <img *ngIf="status === 'completed' || row.value.thumbnail" [src]="thumbUrl()" [alt]="row.value.title" loading="lazy">
+    <span class="thumb-ph" *ngIf="status !== 'completed' && !row.value.thumbnail">
       <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round"><rect x="2" y="4" width="20" height="16" rx="2"/><polyline points="10 9 15 12 10 15"/></svg>
     </span>
     <span class="dur num" *ngIf="row.value.duration">{{ row.value.duration | duration }}</span>