feat: add per-storage manual transcode for browser-incompatible videos

Add a transcode control to each storage in the admin drives page,
modeled after the cover/preview generation controls:

- Manual start/stop button per storage; transcoding is off by default
  and never runs automatically (not triggered by scans or the nightly
  pipeline)
- New transcode worker probes candidates (non mp4/webm extensions)
  with ffprobe: already-compatible files are marked skipped; AVI with
  H.264 is remuxed losslessly; incompatible codecs (MPEG-4 Part 2,
  WMV, RMVB, HEVC...) are transcoded to H.264/AAC MP4 with +faststart
- Transcoded output is uploaded back to the same storage under a
  "91转码" directory which is auto-added to the drive's scan skip list
  so the scanner never re-imports the artifacts
- Playback source automatically prefers the transcoded file once
  ready, keeping the 302 direct-link mode for cloud drives
- videos table gains transcode_status/error/file_id/size columns via
  startup migration; counts and live task status surface in the
  admin drives API and generation panel UI
- Stop semantics: per-drive stop button, drive-level "stop all tasks"
  and global stop all include the transcode task; interrupted videos
  keep their candidate status and resume on next start

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

backend/cmd/server/main.go

@@ -43,6 +43,7 @@ import (
 	"github.com/video-site/backend/internal/proxy"
 	"github.com/video-site/backend/internal/scanner"
 	"github.com/video-site/backend/internal/spider91migrate"
+	"github.com/video-site/backend/internal/transcode"
 )
 
 const fingerprintReconcileInterval = time.Minute
@@ -218,6 +219,12 @@ func main() {
 		OnRegenFailedFingerprints: func(driveID string) {
 			go app.regenFailedFingerprints(ctx, driveID)
 		},
+		OnStartDriveTranscode: func(driveID string) (bool, string) {
+			return app.startDriveTranscode(ctx, driveID)
+		},
+		OnStopDriveTranscode: func(driveID string) bool {
+			return app.stopDriveTranscode(driveID)
+		},
 		OnDeleteVideo: func(reqCtx context.Context, videoID string, deleteSource bool) (api.DeleteVideoResult, error) {
 			return app.deleteVideo(reqCtx, videoID, deleteSource)
 		},
@@ -368,6 +375,13 @@ type App struct {
 	// uploadProgress 跟踪脚本爬虫迁移到云盘时的实时上传状态。
 	uploadProgressMu sync.Mutex
 	uploadProgress   map[string]driveUploadProgress
+
+	// transcodeMu 保护 transcodeWorkers / transcodeCancels。
+	// 浏览器兼容性转码每盘最多一个任务，且只能由管理员手动开启
+	// （不随扫盘/夜间流水线自动运行），手动停止或处理完即从 map 清除。
+	transcodeMu      sync.Mutex
+	transcodeWorkers map[string]*transcode.Worker
+	transcodeCancels map[string]context.CancelFunc
 }
 
 type driveScanProgress struct {
@@ -557,7 +571,14 @@ func (a *App) driveGenerationStatuses() map[string]api.DriveGenerationStatuses {
 	}
 	a.mu.Unlock()
 
-	out := make(map[string]api.DriveGenerationStatuses, len(scanningDrives)+len(previewWorkers)+len(thumbWorkers)+len(fingerprintWorkers)+len(uploadProgresses))
+	a.transcodeMu.Lock()
+	transcodeWorkers := make(map[string]*transcode.Worker, len(a.transcodeWorkers))
+	for id, worker := range a.transcodeWorkers {
+		transcodeWorkers[id] = worker
+	}
+	a.transcodeMu.Unlock()
+
+	out := make(map[string]api.DriveGenerationStatuses, len(scanningDrives)+len(previewWorkers)+len(thumbWorkers)+len(fingerprintWorkers)+len(uploadProgresses)+len(transcodeWorkers))
 	for id, running := range scanningDrives {
 		if !running {
 			continue
@@ -601,6 +622,11 @@ func (a *App) driveGenerationStatuses() map[string]api.DriveGenerationStatuses {
 		}
 		out[id] = status
 	}
+	for id, worker := range transcodeWorkers {
+		status := out[id]
+		status.Transcode = generationStatusFromTranscode(worker.Status())
+		out[id] = status
+	}
 	return out
 }
 
@@ -687,6 +713,126 @@ func generationStatusFromFingerprint(status fingerprint.TaskStatus) api.Generati
 	return out
 }
 
+func generationStatusFromTranscode(status transcode.TaskStatus) api.GenerationStatus {
+	state := status.State
+	if state == "" {
+		state = "idle"
+	}
+	return api.GenerationStatus{
+		State:        state,
+		CurrentTitle: status.CurrentTitle,
+		QueueLength:  status.QueueLength,
+		DoneCount:    status.DoneCount,
+		TotalCount:   status.TotalCount,
+	}
+}
+
+// transcodeWorkDir 返回转码用的本地临时目录（下载原片 / 写产物），与
+// localUploadDir 一样挂在数据目录下，避免 /tmp 空间不足。
+func (a *App) transcodeWorkDir() string {
+	return filepath.Join(filepath.Dir(a.cfg.Storage.LocalPreviewDir), "transcode-tmp")
+}
+
+// startDriveTranscode 手动开启某盘的浏览器兼容性转码。
+// 转码从不自动运行：扫盘、夜间流水线都不会触发，这里是唯一入口。
+// 任务跑完候选列表后自然结束；中途可用 stopDriveTranscode / 停止所有任务中断。
+func (a *App) startDriveTranscode(ctx context.Context, driveID string) (bool, string) {
+	driveID = strings.TrimSpace(driveID)
+	if driveID == "" {
+		return false, "缺少存储 ID"
+	}
+	drv, ok := a.registry.Get(driveID)
+	if !ok {
+		return false, "存储未挂载或不可用"
+	}
+	switch drv.Kind() {
+	case spider91.Kind, scriptcrawler.Kind:
+		return false, "爬虫存储不支持转码"
+	}
+	workDir := a.transcodeWorkDir()
+	if err := os.MkdirAll(workDir, 0o755); err != nil {
+		return false, "创建转码临时目录失败: " + err.Error()
+	}
+
+	a.transcodeMu.Lock()
+	if a.transcodeWorkers == nil {
+		a.transcodeWorkers = make(map[string]*transcode.Worker)
+		a.transcodeCancels = make(map[string]context.CancelFunc)
+	}
+	if existing := a.transcodeWorkers[driveID]; existing != nil {
+		a.transcodeMu.Unlock()
+		return false, "该存储的转码任务已在运行"
+	}
+	worker := transcode.NewWorker(transcode.Config{
+		FFmpegPath:  a.cfg.Preview.FFmpegPath,
+		FFprobePath: a.cfg.Preview.FFprobePath,
+		WorkDir:     workDir,
+	}, a.cat, drv)
+	taskCtx, done := a.registerDriveTaskContext(ctx, driveID)
+	runCtx, cancel := context.WithCancel(taskCtx)
+	a.transcodeWorkers[driveID] = worker
+	a.transcodeCancels[driveID] = cancel
+	a.transcodeMu.Unlock()
+
+	go func() {
+		defer func() {
+			cancel()
+			done()
+			a.transcodeMu.Lock()
+			if a.transcodeWorkers[driveID] == worker {
+				delete(a.transcodeWorkers, driveID)
+				delete(a.transcodeCancels, driveID)
+			}
+			a.transcodeMu.Unlock()
+		}()
+		candidates, err := a.cat.ListTranscodeCandidates(runCtx, driveID, 0)
+		if err != nil {
+			log.Printf("[transcode] list candidates drive=%s: %v", driveID, err)
+			return
+		}
+		if len(candidates) == 0 {
+			log.Printf("[transcode] drive=%s no candidates", driveID)
+			return
+		}
+		log.Printf("[transcode] drive=%s start, %d candidates", driveID, len(candidates))
+		worker.Run(runCtx, candidates)
+	}()
+	return true, ""
+}
+
+// stopAllDriveTranscodes 停掉所有盘的转码任务，返回被停的 driveID 列表。
+func (a *App) stopAllDriveTranscodes() []string {
+	a.transcodeMu.Lock()
+	cancels := a.transcodeCancels
+	a.transcodeCancels = nil
+	a.transcodeWorkers = nil
+	a.transcodeMu.Unlock()
+	ids := make([]string, 0, len(cancels))
+	for id, cancel := range cancels {
+		if cancel != nil {
+			cancel()
+		}
+		ids = append(ids, id)
+	}
+	return ids
+}
+
+// stopDriveTranscode 手动停止某盘的转码任务。返回是否有任务被停。
+func (a *App) stopDriveTranscode(driveID string) bool {
+	driveID = strings.TrimSpace(driveID)
+	a.transcodeMu.Lock()
+	cancel := a.transcodeCancels[driveID]
+	delete(a.transcodeCancels, driveID)
+	delete(a.transcodeWorkers, driveID)
+	a.transcodeMu.Unlock()
+	if cancel == nil {
+		return false
+	}
+	cancel()
+	log.Printf("[transcode] stop drive=%s", driveID)
+	return true
+}
+
 func (a *App) attachDrive(ctx context.Context, d *catalog.Drive) error {
 	a.driveAttachMu.Lock()
 	defer a.driveAttachMu.Unlock()
@@ -1435,10 +1581,11 @@ func (a *App) stopDriveTasks(ctx context.Context, driveID string) bool {
 	queued := a.clearQueuedDriveTask(driveID)
 	fingerprintQueued := a.clearFingerprintQueueing(driveID)
 	uploading := a.clearCrawlerUploadProgress(driveID)
+	transcoding := a.stopDriveTranscode(driveID)
 	hadWorkers := a.resetDriveGenerationWorkers(ctx, driveID)
-	stopped := canceled > 0 || queued || fingerprintQueued || uploading || hadWorkers
-	log.Printf("[tasks] stop drive=%s stopped=%v canceled_tasks=%d queued=%v fingerprint_queue=%v uploading=%v workers=%v",
-		driveID, stopped, canceled, queued, fingerprintQueued, uploading, hadWorkers)
+	stopped := canceled > 0 || queued || fingerprintQueued || uploading || transcoding || hadWorkers
+	log.Printf("[tasks] stop drive=%s stopped=%v canceled_tasks=%d queued=%v fingerprint_queue=%v uploading=%v transcoding=%v workers=%v",
+		driveID, stopped, canceled, queued, fingerprintQueued, uploading, transcoding, hadWorkers)
 	return stopped
 }
 
@@ -1459,6 +1606,9 @@ func (a *App) stopAllDriveTasks(ctx context.Context) int {
 	for _, id := range a.clearAllCrawlerUploadProgress() {
 		stoppedIDs[id] = struct{}{}
 	}
+	for _, id := range a.stopAllDriveTranscodes() {
+		stoppedIDs[id] = struct{}{}
+	}
 	for _, id := range a.resetAllDriveGenerationWorkers(ctx) {
 		stoppedIDs[id] = struct{}{}
 	}

backend/internal/api/admin.go

@@ -59,7 +59,13 @@ type AdminServer struct {
 	OnRegenFailedPreviews      func(driveID string)
 	OnRegenFailedThumbnails    func(driveID string)
 	OnRegenFailedFingerprints  func(driveID string)
-	OnDeleteVideo              func(ctx context.Context, videoID string, deleteSource bool) (DeleteVideoResult, error)
+	// OnStartDriveTranscode 手动开启某盘的浏览器兼容性转码任务。
+	// 返回 (是否接受, 拒绝原因)。转码从不自动运行，只能在这里手动触发；
+	// 处理完候选列表后任务自然结束。
+	OnStartDriveTranscode func(driveID string) (bool, string)
+	// OnStopDriveTranscode 手动停止某盘正在进行的转码任务。返回是否有任务被停。
+	OnStopDriveTranscode func(driveID string) bool
+	OnDeleteVideo        func(ctx context.Context, videoID string, deleteSource bool) (DeleteVideoResult, error)
 	GetDriveGenerationStatuses func() map[string]DriveGenerationStatuses
 	// OnTeaserEnabledChanged 在 per-drive 预览视频开关被切换后调用。
 	// enabled=true 时上层应该重新把 pending 预览视频入队（类似旧的全局开关从关到开）；
@@ -118,6 +124,7 @@ type DriveGenerationStatuses struct {
 	Preview     GenerationStatus `json:"preview"`
 	Fingerprint GenerationStatus `json:"fingerprint"`
 	Upload      GenerationStatus `json:"upload"`
+	Transcode   GenerationStatus `json:"transcode"`
 }
 
 type NightlyJobStatus struct {
@@ -169,6 +176,8 @@ func (a *AdminServer) Register(r chi.Router) {
 			r.Post("/drives/{id}/previews/failed/regenerate", a.handleRegenFailedPreviews)
 			r.Post("/drives/{id}/thumbnails/failed/regenerate", a.handleRegenFailedThumbnails)
 			r.Post("/drives/{id}/fingerprints/failed/regenerate", a.handleRegenFailedFingerprints)
+			r.Post("/drives/{id}/transcode/start", a.handleStartDriveTranscode)
+			r.Post("/drives/{id}/transcode/stop", a.handleStopDriveTranscode)
 
 			// 爬虫
 			r.Get("/crawlers", a.handleListCrawlers)
@@ -431,6 +440,11 @@ func (a *AdminServer) handleListDrives(w http.ResponseWriter, r *http.Request) {
 		writeErr(w, http.StatusInternalServerError, err)
 		return
 	}
+	transcodeCounts, err := a.Catalog.CountTranscodesByDrive(r.Context())
+	if err != nil {
+		writeErr(w, http.StatusInternalServerError, err)
+		return
+	}
 	generationStatuses := map[string]DriveGenerationStatuses{}
 	if a.GetDriveGenerationStatuses != nil {
 		generationStatuses = a.GetDriveGenerationStatuses()
@@ -470,6 +484,11 @@ func (a *AdminServer) handleListDrives(w http.ResponseWriter, r *http.Request) {
 		FingerprintReadyCount         int              `json:"fingerprintReadyCount"`
 		FingerprintPendingCount       int              `json:"fingerprintPendingCount"`
 		FingerprintFailedCount        int              `json:"fingerprintFailedCount"`
+		TranscodeGenerationStatus     GenerationStatus `json:"transcodeGenerationStatus"`
+		TranscodePendingCount         int              `json:"transcodePendingCount"`
+		TranscodeReadyCount           int              `json:"transcodeReadyCount"`
+		TranscodeFailedCount          int              `json:"transcodeFailedCount"`
+		TranscodeSkippedCount         int              `json:"transcodeSkippedCount"`
 	}
 	list := make([]out, 0, len(drives))
 	for _, d := range drives {
@@ -479,6 +498,7 @@ func (a *AdminServer) handleListDrives(w http.ResponseWriter, r *http.Request) {
 		counts := teaserCounts[d.ID]
 		thumbCounts := thumbnailCounts[d.ID]
 		fingerprintCount := fingerprintCounts[d.ID]
+		transcodeCount := transcodeCounts[d.ID]
 		generation := generationStatuses[d.ID]
 		if generation.Scan.State == "" {
 			generation.Scan.State = "idle"
@@ -492,6 +512,9 @@ func (a *AdminServer) handleListDrives(w http.ResponseWriter, r *http.Request) {
 		if generation.Fingerprint.State == "" {
 			generation.Fingerprint.State = "idle"
 		}
+		if generation.Transcode.State == "" {
+			generation.Transcode.State = "idle"
+		}
 		// spider91 没有用户凭证概念；只要存在 drive 行就视为"已配置"。
 		// last_crawl_at 是后端自动写入的运行状态字段，不计入 hasCredential 判定。
 		hasCred := false
@@ -537,6 +560,11 @@ func (a *AdminServer) handleListDrives(w http.ResponseWriter, r *http.Request) {
 			FingerprintReadyCount:         fingerprintCount.Ready,
 			FingerprintPendingCount:       fingerprintCount.Pending,
 			FingerprintFailedCount:        fingerprintCount.Failed,
+			TranscodeGenerationStatus:     generation.Transcode,
+			TranscodePendingCount:         transcodeCount.Pending,
+			TranscodeReadyCount:           transcodeCount.Ready,
+			TranscodeFailedCount:          transcodeCount.Failed,
+			TranscodeSkippedCount:         transcodeCount.Skipped,
 		})
 	}
 	writeJSON(w, http.StatusOK, list)
@@ -1547,6 +1575,35 @@ func (a *AdminServer) handleStopDriveTasks(w http.ResponseWriter, r *http.Reques
 	})
 }
 
+// handleStartDriveTranscode 手动开启某盘的浏览器兼容性转码。
+// 转码默认不开启、从不自动运行；本接口是唯一入口。
+func (a *AdminServer) handleStartDriveTranscode(w http.ResponseWriter, r *http.Request) {
+	id := chi.URLParam(r, "id")
+	if a.OnStartDriveTranscode == nil {
+		writeErr(w, http.StatusNotImplemented, errors.New("transcode not supported"))
+		return
+	}
+	accepted, message := a.OnStartDriveTranscode(id)
+	writeJSON(w, http.StatusAccepted, map[string]any{
+		"ok":       true,
+		"accepted": accepted,
+		"message":  message,
+	})
+}
+
+// handleStopDriveTranscode 手动停止某盘正在进行的转码任务。
+func (a *AdminServer) handleStopDriveTranscode(w http.ResponseWriter, r *http.Request) {
+	id := chi.URLParam(r, "id")
+	stopped := false
+	if a.OnStopDriveTranscode != nil {
+		stopped = a.OnStopDriveTranscode(id)
+	}
+	writeJSON(w, http.StatusAccepted, map[string]any{
+		"ok":      true,
+		"stopped": stopped,
+	})
+}
+
 func (a *AdminServer) p123QRClient() *p123.QRClient {
 	return p123.NewQRClient(p123.QRConfig{
 		UserAPIBaseURL: a.P123UserAPIBaseURL,

backend/internal/api/api.go

@@ -970,6 +970,15 @@ func thumbnailURL(v *catalog.Video) string {
 	return base + "?v=" + strconv.FormatInt(v.UpdatedAt.UnixMilli(), 10)
 }
 
+// transcodedSource 在视频有就绪的浏览器兼容性转码产物时返回产物的播放地址。
+// 产物和原始文件在同一个 drive 上，走同一条 /p/stream 代理/302 链路。
+func transcodedSource(v *catalog.Video) (string, bool) {
+	if v.TranscodeStatus == "ready" && v.TranscodedFileID != "" && v.DriveID != localUploadDriveID {
+		return fmt.Sprintf("/p/stream/%s/%s", pathSegment(v.DriveID), pathSegment(v.TranscodedFileID)), true
+	}
+	return "", false
+}
+
 func (s *Server) videoSource(v *catalog.Video) string {
 	if v.DriveID == localUploadDriveID {
 		return "/p/upload/" + pathSegment(v.ID)
@@ -982,6 +991,9 @@ func (s *Server) videoSource(v *catalog.Video) string {
 			}
 		}
 	}
+	if src, ok := transcodedSource(v); ok {
+		return src
+	}
 	return fmt.Sprintf("/p/stream/%s/%s", pathSegment(v.DriveID), pathSegment(v.FileID))
 }
 
@@ -991,6 +1003,9 @@ func videoSource(v *catalog.Video) string {
 	if v.DriveID == localUploadDriveID {
 		return "/p/upload/" + pathSegment(v.ID)
 	}
+	if src, ok := transcodedSource(v); ok {
+		return src
+	}
 	return fmt.Sprintf("/p/stream/%s/%s", pathSegment(v.DriveID), pathSegment(v.FileID))
 }
 

backend/internal/catalog/catalog.go

@@ -71,6 +71,12 @@ type Video struct {
 	PreviewFileID     string    `json:"previewFileId"`
 	PreviewLocal      string    `json:"previewLocal"`
 	PreviewStatus     string    `json:"previewStatus"`
+	// TranscodeStatus：浏览器兼容性转码状态。
+	// ''=未检测 / pending=已入队 / ready=已转码 / skipped=无需转码 / failed=失败。
+	TranscodeStatus  string `json:"transcodeStatus"`
+	TranscodeError   string `json:"transcodeError"`
+	TranscodedFileID string `json:"transcodedFileId"`
+	TranscodedSize   int64  `json:"transcodedSize"`
 	Views             int       `json:"views"`
 	Favorites         int       `json:"favorites"`
 	Comments          int       `json:"comments"`
@@ -190,6 +196,84 @@ func (c *Catalog) UpdatePreview(ctx context.Context, id, previewLocal, status st
 	return err
 }
 
+// transcodeCandidateWhereSQL 圈定"可能需要浏览器兼容性转码"的视频：
+// mp4/webm/m4v 默认浏览器可播不进候选；strm 是远程引用没有本体。
+// 其余扩展名都先入候选，由转码 worker probe 实际编码后决定转码还是跳过
+// （skipped）。failed 也保留在候选里，重新点开始转码时会自动重试。
+const transcodeCandidateWhereSQL = `COALESCE(ext, '') NOT IN ('mp4', 'webm', 'm4v', 'strm')
+	AND COALESCE(transcode_status, '') IN ('', 'pending', 'failed')`
+
+// ListTranscodeCandidates 列出某盘所有转码候选视频。limit<=0 表示不限制。
+func (c *Catalog) ListTranscodeCandidates(ctx context.Context, driveID string, limit int) ([]*Video, error) {
+	query := `SELECT ` + allVideoCols + ` FROM videos
+		 WHERE drive_id = ? AND ` + transcodeCandidateWhereSQL + `
+		 ORDER BY created_at ASC, id ASC`
+	args := []any{driveID}
+	if limit > 0 {
+		query += ` LIMIT ?`
+		args = append(args, limit)
+	}
+	rows, err := c.db.QueryContext(ctx, query, args...)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var out []*Video
+	for rows.Next() {
+		v, err := scanVideo(rows)
+		if err != nil {
+			return nil, err
+		}
+		out = append(out, v)
+	}
+	return out, rows.Err()
+}
+
+// UpdateVideoTranscode 写回单条视频的转码结果。
+// status=ready 时 transcodedFileID/transcodedSize 指向转码产物；
+// 其它 status 调用方应传空值，本函数会按传入值原样覆盖。
+func (c *Catalog) UpdateVideoTranscode(ctx context.Context, id, status, errMsg, transcodedFileID string, transcodedSize int64) error {
+	_, err := c.db.ExecContext(ctx,
+		`UPDATE videos SET transcode_status = ?, transcode_error = ?, transcoded_file_id = ?, transcoded_size = ?, updated_at = ? WHERE id = ?`,
+		status, errMsg, transcodedFileID, transcodedSize, time.Now().UnixMilli(), id)
+	return err
+}
+
+// DriveTranscodeCounts 是单盘的转码进度统计。
+type DriveTranscodeCounts struct {
+	// Pending 是仍在候选集合里、还没有出结果的数量（含从未检测过的）。
+	Pending int
+	Ready   int
+	Failed  int
+	Skipped int
+}
+
+func (c *Catalog) CountTranscodesByDrive(ctx context.Context) (map[string]DriveTranscodeCounts, error) {
+	rows, err := c.db.QueryContext(ctx, `
+		SELECT drive_id,
+		        COUNT(CASE WHEN COALESCE(ext, '') NOT IN ('mp4', 'webm', 'm4v', 'strm')
+		                    AND COALESCE(transcode_status, '') IN ('', 'pending') THEN 1 END) AS pending_count,
+		        COUNT(CASE WHEN COALESCE(transcode_status, '') = 'ready' THEN 1 END) AS ready_count,
+		        COUNT(CASE WHEN COALESCE(transcode_status, '') = 'failed' THEN 1 END) AS failed_count,
+		        COUNT(CASE WHEN COALESCE(transcode_status, '') = 'skipped' THEN 1 END) AS skipped_count
+		  FROM videos
+		 GROUP BY drive_id`)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	out := make(map[string]DriveTranscodeCounts)
+	for rows.Next() {
+		var driveID string
+		var counts DriveTranscodeCounts
+		if err := rows.Scan(&driveID, &counts.Pending, &counts.Ready, &counts.Failed, &counts.Skipped); err != nil {
+			return nil, err
+		}
+		out[driveID] = counts
+	}
+	return out, rows.Err()
+}
+
 func (c *Catalog) HideVideo(ctx context.Context, id string) error {
 	res, err := c.db.ExecContext(ctx,
 		`UPDATE videos SET hidden = 1, updated_at = ? WHERE id = ?`,
@@ -2165,6 +2249,7 @@ COALESCE(sampled_sha256, ''), COALESCE(fingerprint_status, 'pending'), COALESCE(
 COALESCE(parent_id, ''), title, COALESCE(author, ''), COALESCE(tags, '[]'),
 duration_seconds, size_bytes, COALESCE(ext, ''), COALESCE(quality, ''), COALESCE(thumbnail_url, ''),
 COALESCE(preview_file_id, ''), COALESCE(preview_local, ''), COALESCE(preview_status, 'pending'),
+COALESCE(transcode_status, ''), COALESCE(transcode_error, ''), COALESCE(transcoded_file_id, ''), COALESCE(transcoded_size, 0),
 views, favorites, comments, likes, dislikes,
 COALESCE(category, ''), COALESCE(hidden, 0), COALESCE(badges, '[]'), COALESCE(description, ''),
 published_at, created_at, updated_at
@@ -2236,6 +2321,7 @@ func scanVideo(row rowScanner) (*Video, error) {
 		&v.ParentID, &v.Title, &v.Author, &tagsJSON,
 		&v.DurationSeconds, &v.Size, &v.Ext, &v.Quality, &v.ThumbnailURL,
 		&v.PreviewFileID, &v.PreviewLocal, &v.PreviewStatus,
+		&v.TranscodeStatus, &v.TranscodeError, &v.TranscodedFileID, &v.TranscodedSize,
 		&v.Views, &v.Favorites, &v.Comments, &v.Likes, &v.Dislikes,
 		&v.Category, &hidden, &badgesJSON, &v.Description,
 		&publishedAt, &createdAt, &updatedAt,

backend/internal/catalog/schema.sql

@@ -22,6 +22,10 @@ CREATE TABLE IF NOT EXISTS videos (
     preview_file_id  TEXT,                      -- deprecated: 旧版回写网盘后的预览视频 file id
     preview_local    TEXT,                      -- 本地预览视频路径（兜底）
     preview_status   TEXT DEFAULT 'pending',    -- pending / ready / failed
+    transcode_status TEXT DEFAULT '',           -- '' / pending / ready / skipped / failed（浏览器兼容性转码）
+    transcode_error  TEXT DEFAULT '',
+    transcoded_file_id TEXT DEFAULT '',         -- 转码产物在同一 drive 上的 fileID，播放源优先用它
+    transcoded_size  INTEGER DEFAULT 0,
     views            INTEGER DEFAULT 0,
     favorites        INTEGER DEFAULT 0,
     comments         INTEGER DEFAULT 0,

backend/internal/catalog/tags.go

@@ -66,6 +66,21 @@ func (c *Catalog) migrate(ctx context.Context) error {
 	if err := c.addColumnIfMissing(ctx, "videos", "thumbnail_failures", "INTEGER DEFAULT 0"); err != nil {
 		return err
 	}
+	// videos.transcode_*：浏览器兼容性转码状态。
+	// status：''=未检测 / pending=已入队 / ready=已转码 / skipped=检测后无需转码 / failed=失败。
+	// transcoded_file_id 指向转码产物在同一 drive 上的 fileID，播放源优先使用它。
+	if err := c.addColumnIfMissing(ctx, "videos", "transcode_status", "TEXT DEFAULT ''"); err != nil {
+		return err
+	}
+	if err := c.addColumnIfMissing(ctx, "videos", "transcode_error", "TEXT DEFAULT ''"); err != nil {
+		return err
+	}
+	if err := c.addColumnIfMissing(ctx, "videos", "transcoded_file_id", "TEXT DEFAULT ''"); err != nil {
+		return err
+	}
+	if err := c.addColumnIfMissing(ctx, "videos", "transcoded_size", "INTEGER DEFAULT 0"); err != nil {
+		return err
+	}
 	// drives.teaser_enabled：每盘预览视频开关，替代旧的全局 preview.enabled。
 	// 升级路径：直接让 ALTER TABLE 的 DEFAULT 1 兜底 —— 每个现存 drive 都默认开启，
 	// 不读旧的 settings.preview.enabled 字段。这样老用户即便之前关过全局开关，

backend/internal/transcode/transcode.go

@@ -0,0 +1,178 @@
+// Package transcode 实现"浏览器兼容性转码"：把网盘/本地存储中浏览器
+// <video> 播不动的视频（AVI/WMV/FLV、MPEG-4 Part 2、RMVB 等）转成
+// H.264 + AAC 的 MP4，并把产物上传回同一存储，播放源切到产物文件。
+//
+// 与封面/预览生成不同，转码不会自动运行——只能由管理员在网盘管理页
+// 手动开启，也可以随时手动停止。
+package transcode
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"os/exec"
+	"strings"
+	"time"
+)
+
+// MediaInfo 是 ffprobe 探测出来的、做兼容性判定所需的最小信息。
+type MediaInfo struct {
+	// FormatName 是 ffprobe 的 format_name，逗号分隔的 demuxer 别名，
+	// 例如 "mov,mp4,m4a,3gp,3g2,mj2" / "avi" / "matroska,webm"。
+	FormatName  string
+	VideoCodecs []string
+	AudioCodecs []string
+}
+
+// browserCompatibleVideoCodecs 是主流浏览器 <video> 普遍可解码的视频编码。
+// HEVC/H.265 只有部分平台支持，保守起见不算兼容。
+var browserCompatibleVideoCodecs = map[string]bool{
+	"h264": true,
+	"vp8":  true,
+	"vp9":  true,
+	"av1":  true,
+}
+
+// browserCompatibleAudioCodecs 是主流浏览器普遍可解码的音频编码。
+var browserCompatibleAudioCodecs = map[string]bool{
+	"aac":    true,
+	"mp3":    true,
+	"opus":   true,
+	"vorbis": true,
+	"flac":   true,
+}
+
+// NeedsTranscode 判断这个文件是否需要转码才能在浏览器里播放。
+// ext 是 catalog 里记录的扩展名（小写、不带点），用来区分 mkv 和 webm
+// （两者的 format_name 都是 "matroska,webm"）。
+func NeedsTranscode(info MediaInfo, ext string) bool {
+	if !containerCompatible(info.FormatName, ext) {
+		return true
+	}
+	for _, codec := range info.VideoCodecs {
+		if !browserCompatibleVideoCodecs[strings.ToLower(codec)] {
+			return true
+		}
+	}
+	for _, codec := range info.AudioCodecs {
+		if !browserCompatibleAudioCodecs[strings.ToLower(codec)] {
+			return true
+		}
+	}
+	return false
+}
+
+func containerCompatible(formatName, ext string) bool {
+	format := strings.ToLower(formatName)
+	for _, name := range strings.Split(format, ",") {
+		if name == "mp4" {
+			return true
+		}
+	}
+	// matroska,webm：只有真 .webm 信任为浏览器可播容器；.mkv 保守转码。
+	if strings.Contains(format, "webm") && strings.EqualFold(ext, "webm") {
+		return true
+	}
+	return false
+}
+
+// ProbeFile 用 ffprobe 探测本地文件的容器与音视频编码。
+func ProbeFile(ctx context.Context, ffprobePath, path string) (MediaInfo, error) {
+	ctx2, cancel := context.WithTimeout(ctx, 60*time.Second)
+	defer cancel()
+	cmd := exec.CommandContext(ctx2, ffprobePath,
+		"-v", "error",
+		"-show_entries", "format=format_name",
+		"-show_entries", "stream=codec_type,codec_name",
+		"-of", "json",
+		path,
+	)
+	out, err := cmd.Output()
+	if err != nil {
+		return MediaInfo{}, fmt.Errorf("transcode: ffprobe: %w", err)
+	}
+	var parsed struct {
+		Format struct {
+			FormatName string `json:"format_name"`
+		} `json:"format"`
+		Streams []struct {
+			CodecType string `json:"codec_type"`
+			CodecName string `json:"codec_name"`
+		} `json:"streams"`
+	}
+	if err := json.Unmarshal(out, &parsed); err != nil {
+		return MediaInfo{}, fmt.Errorf("transcode: parse ffprobe output: %w", err)
+	}
+	info := MediaInfo{FormatName: parsed.Format.FormatName}
+	for _, s := range parsed.Streams {
+		switch s.CodecType {
+		case "video":
+			info.VideoCodecs = append(info.VideoCodecs, s.CodecName)
+		case "audio":
+			info.AudioCodecs = append(info.AudioCodecs, s.CodecName)
+		}
+	}
+	return info, nil
+}
+
+// buildFFmpegArgs 按探测结果生成转码参数：
+//   - 编码本就兼容、只是容器不行（如 AVI 里装 H.264）→ 流拷贝 remux，零质量损失；
+//   - 否则视频转 H.264（裁到偶数尺寸 + yuv420p 保证兼容性）、音频转 AAC。
+//
+// 两种情况都加 +faststart 把 moov 提前，便于边下边播。
+func buildFFmpegArgs(info MediaInfo, inPath, outPath string) []string {
+	args := []string{"-y", "-i", inPath}
+	videoOK := true
+	for _, codec := range info.VideoCodecs {
+		if !browserCompatibleVideoCodecs[strings.ToLower(codec)] {
+			videoOK = false
+			break
+		}
+	}
+	audioOK := true
+	for _, codec := range info.AudioCodecs {
+		if !browserCompatibleAudioCodecs[strings.ToLower(codec)] {
+			audioOK = false
+			break
+		}
+	}
+	if videoOK {
+		args = append(args, "-c:v", "copy")
+	} else {
+		args = append(args,
+			"-c:v", "libx264",
+			"-preset", "veryfast",
+			"-crf", "23",
+			"-vf", "scale=trunc(iw/2)*2:trunc(ih/2)*2",
+			"-pix_fmt", "yuv420p",
+		)
+	}
+	if len(info.AudioCodecs) == 0 {
+		args = append(args, "-an")
+	} else if audioOK {
+		args = append(args, "-c:a", "copy")
+	} else {
+		args = append(args, "-c:a", "aac", "-b:a", "128k")
+	}
+	args = append(args, "-movflags", "+faststart", "-f", "mp4", outPath)
+	return args
+}
+
+// TranscodeFile 把本地输入文件转成浏览器可播的 MP4 写到 outPath。
+func TranscodeFile(ctx context.Context, ffmpegPath string, info MediaInfo, inPath, outPath string) error {
+	args := buildFFmpegArgs(info, inPath, outPath)
+	cmd := exec.CommandContext(ctx, ffmpegPath, args...)
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		return fmt.Errorf("transcode: ffmpeg: %w: %s", err, tailOf(string(out), 400))
+	}
+	return nil
+}
+
+func tailOf(s string, n int) string {
+	s = strings.TrimSpace(s)
+	if len(s) <= n {
+		return s
+	}
+	return s[len(s)-n:]
+}

backend/internal/transcode/transcode_test.go

@@ -0,0 +1,125 @@
+package transcode
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/video-site/backend/internal/catalog"
+)
+
+func TestNeedsTranscode(t *testing.T) {
+	cases := []struct {
+		name string
+		info MediaInfo
+		ext  string
+		want bool
+	}{
+		{
+			name: "h264 aac mp4 is compatible",
+			info: MediaInfo{FormatName: "mov,mp4,m4a,3gp,3g2,mj2", VideoCodecs: []string{"h264"}, AudioCodecs: []string{"aac"}},
+			ext:  "mp4",
+			want: false,
+		},
+		{
+			name: "mpeg4 in avi needs transcode",
+			info: MediaInfo{FormatName: "avi", VideoCodecs: []string{"mpeg4"}, AudioCodecs: []string{"mp3"}},
+			ext:  "avi",
+			want: true,
+		},
+		{
+			name: "h264 in avi needs remux",
+			info: MediaInfo{FormatName: "avi", VideoCodecs: []string{"h264"}, AudioCodecs: []string{"aac"}},
+			ext:  "avi",
+			want: true,
+		},
+		{
+			name: "hevc in mp4 needs transcode",
+			info: MediaInfo{FormatName: "mov,mp4,m4a,3gp,3g2,mj2", VideoCodecs: []string{"hevc"}, AudioCodecs: []string{"aac"}},
+			ext:  "mp4",
+			want: true,
+		},
+		{
+			name: "vp9 opus webm is compatible",
+			info: MediaInfo{FormatName: "matroska,webm", VideoCodecs: []string{"vp9"}, AudioCodecs: []string{"opus"}},
+			ext:  "webm",
+			want: false,
+		},
+		{
+			name: "h264 in mkv is conservative transcode",
+			info: MediaInfo{FormatName: "matroska,webm", VideoCodecs: []string{"h264"}, AudioCodecs: []string{"aac"}},
+			ext:  "mkv",
+			want: true,
+		},
+		{
+			name: "pcm audio in mov needs transcode",
+			info: MediaInfo{FormatName: "mov,mp4,m4a,3gp,3g2,mj2", VideoCodecs: []string{"h264"}, AudioCodecs: []string{"pcm_s16le"}},
+			ext:  "mov",
+			want: true,
+		},
+		{
+			name: "video only h264 mp4 is compatible",
+			info: MediaInfo{FormatName: "mov,mp4,m4a,3gp,3g2,mj2", VideoCodecs: []string{"h264"}},
+			ext:  "mp4",
+			want: false,
+		},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			if got := NeedsTranscode(tc.info, tc.ext); got != tc.want {
+				t.Fatalf("NeedsTranscode(%+v, %q) = %v, want %v", tc.info, tc.ext, got, tc.want)
+			}
+		})
+	}
+}
+
+func TestBuildFFmpegArgsRemuxWhenCodecsCompatible(t *testing.T) {
+	// AVI 里装 H.264+AAC：只需要换容器，应该走流拷贝
+	info := MediaInfo{FormatName: "avi", VideoCodecs: []string{"h264"}, AudioCodecs: []string{"aac"}}
+	args := strings.Join(buildFFmpegArgs(info, "in.avi", "out.mp4"), " ")
+	if !strings.Contains(args, "-c:v copy") {
+		t.Fatalf("expected video stream copy, got: %s", args)
+	}
+	if !strings.Contains(args, "-c:a copy") {
+		t.Fatalf("expected audio stream copy, got: %s", args)
+	}
+	if !strings.Contains(args, "+faststart") {
+		t.Fatalf("expected faststart flag, got: %s", args)
+	}
+}
+
+func TestBuildFFmpegArgsTranscodesIncompatibleCodecs(t *testing.T) {
+	info := MediaInfo{FormatName: "avi", VideoCodecs: []string{"mpeg4"}, AudioCodecs: []string{"wmav2"}}
+	args := strings.Join(buildFFmpegArgs(info, "in.avi", "out.mp4"), " ")
+	if !strings.Contains(args, "-c:v libx264") {
+		t.Fatalf("expected libx264 video encode, got: %s", args)
+	}
+	if !strings.Contains(args, "-c:a aac") {
+		t.Fatalf("expected aac audio encode, got: %s", args)
+	}
+	if !strings.Contains(args, "yuv420p") {
+		t.Fatalf("expected yuv420p pixel format, got: %s", args)
+	}
+}
+
+func TestBuildFFmpegArgsDropsAudioWhenNoAudioStream(t *testing.T) {
+	info := MediaInfo{FormatName: "avi", VideoCodecs: []string{"mpeg4"}}
+	args := strings.Join(buildFFmpegArgs(info, "in.avi", "out.mp4"), " ")
+	if !strings.Contains(args, "-an") {
+		t.Fatalf("expected -an for video without audio, got: %s", args)
+	}
+}
+
+func TestTranscodedName(t *testing.T) {
+	for _, tc := range []struct {
+		fileName, title, id, want string
+	}{
+		{"www.98T.la@167.avi", "www.98T.la@167", "p115-1", "www.98T.la@167.mp4"},
+		{"", "标题", "p115-2", "标题.mp4"},
+		{"a/b\\c.wmv", "", "p115-3", "a_b_c.mp4"},
+	} {
+		v := &catalog.Video{FileName: tc.fileName, Title: tc.title, ID: tc.id}
+		if got := transcodedName(v); got != tc.want {
+			t.Fatalf("transcodedName(%q,%q,%q) = %q, want %q", tc.fileName, tc.title, tc.id, got, tc.want)
+		}
+	}
+}

backend/internal/transcode/worker.go

@@ -0,0 +1,308 @@
+package transcode
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"net/url"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/video-site/backend/internal/catalog"
+	"github.com/video-site/backend/internal/drives"
+)
+
+// DefaultTargetDirName 是转码产物在网盘上的存放目录（相对根目录）。
+// worker 第一次上传前会 EnsureDir 并把该目录加进 drive 的扫描跳过列表，
+// 避免 scanner 把转码产物当成新视频重复入库。
+const DefaultTargetDirName = "91转码"
+
+type Config struct {
+	FFmpegPath  string
+	FFprobePath string
+	// WorkDir 是下载原始文件 / 写转码产物的本地临时目录。
+	WorkDir string
+	// TargetDirName 为空时用 DefaultTargetDirName。
+	TargetDirName string
+}
+
+// TaskStatus 与 preview/fingerprint worker 的状态结构对齐，供 admin 展示。
+type TaskStatus struct {
+	State        string
+	CurrentTitle string
+	QueueLength  int
+	DoneCount    int
+	TotalCount   int
+}
+
+// Worker 串行处理一个 drive 的转码任务。生命周期与一次"开始转码"对应：
+// Run 处理完整个候选列表（或 ctx 被取消）后即结束，不常驻。
+type Worker struct {
+	cfg Config
+	cat *catalog.Catalog
+	drv drives.Drive
+	hc  *http.Client
+
+	mu           sync.Mutex
+	state        string
+	currentTitle string
+	done         int
+	total        int
+
+	targetDirOnce sync.Once
+	targetDirID   string
+	targetDirErr  error
+}
+
+func NewWorker(cfg Config, cat *catalog.Catalog, drv drives.Drive) *Worker {
+	if cfg.FFmpegPath == "" {
+		cfg.FFmpegPath = "ffmpeg"
+	}
+	if cfg.FFprobePath == "" {
+		cfg.FFprobePath = "ffprobe"
+	}
+	if cfg.TargetDirName == "" {
+		cfg.TargetDirName = DefaultTargetDirName
+	}
+	if cfg.WorkDir == "" {
+		cfg.WorkDir = os.TempDir()
+	}
+	return &Worker{
+		cfg:   cfg,
+		cat:   cat,
+		drv:   drv,
+		hc:    &http.Client{Timeout: 0},
+		state: "idle",
+	}
+}
+
+func (w *Worker) Status() TaskStatus {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	queueLen := w.total - w.done
+	if w.state == "generating" && queueLen > 0 {
+		// 正在处理的那条不算"排队中"
+		queueLen--
+	}
+	if queueLen < 0 {
+		queueLen = 0
+	}
+	return TaskStatus{
+		State:        w.state,
+		CurrentTitle: w.currentTitle,
+		QueueLength:  queueLen,
+		DoneCount:    w.done,
+		TotalCount:   w.total,
+	}
+}
+
+// Run 串行转码整个候选列表。ctx 取消时停在当前条目边界（正在跑的 ffmpeg
+// 会被 CommandContext 杀掉），未处理的候选保持原状态，下次开始时继续。
+func (w *Worker) Run(ctx context.Context, videos []*catalog.Video) {
+	w.mu.Lock()
+	w.state = "generating"
+	w.total = len(videos)
+	w.done = 0
+	w.mu.Unlock()
+
+	defer func() {
+		w.mu.Lock()
+		w.state = "idle"
+		w.currentTitle = ""
+		w.mu.Unlock()
+	}()
+
+	for _, v := range videos {
+		if ctx.Err() != nil {
+			log.Printf("[transcode] drive=%s canceled after %d/%d", w.drv.ID(), w.doneCount(), len(videos))
+			return
+		}
+		w.mu.Lock()
+		w.currentTitle = v.Title
+		w.mu.Unlock()
+
+		if err := w.process(ctx, v); err != nil {
+			if ctx.Err() != nil {
+				// 取消导致的失败不要写 failed，保持候选状态便于下次继续
+				log.Printf("[transcode] drive=%s canceled while processing %s", w.drv.ID(), v.ID)
+				return
+			}
+			log.Printf("[transcode] drive=%s video=%s failed: %v", w.drv.ID(), v.ID, err)
+			if uerr := w.cat.UpdateVideoTranscode(context.WithoutCancel(ctx), v.ID, "failed", err.Error(), "", 0); uerr != nil {
+				log.Printf("[transcode] mark failed %s: %v", v.ID, uerr)
+			}
+		}
+		w.mu.Lock()
+		w.done++
+		w.mu.Unlock()
+	}
+	log.Printf("[transcode] drive=%s finished %d videos", w.drv.ID(), len(videos))
+}
+
+func (w *Worker) doneCount() int {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	return w.done
+}
+
+func (w *Worker) process(ctx context.Context, v *catalog.Video) error {
+	localPath, cleanup, err := w.fetchSource(ctx, v)
+	if err != nil {
+		return fmt.Errorf("fetch source: %w", err)
+	}
+	defer cleanup()
+
+	info, err := ProbeFile(ctx, w.cfg.FFprobePath, localPath)
+	if err != nil {
+		return err
+	}
+	if !NeedsTranscode(info, v.Ext) {
+		log.Printf("[transcode] drive=%s video=%s compatible (%s), skip", w.drv.ID(), v.ID, info.FormatName)
+		return w.cat.UpdateVideoTranscode(ctx, v.ID, "skipped", "", "", 0)
+	}
+
+	outPath := filepath.Join(w.cfg.WorkDir, sanitizeFileName(v.ID)+".transcoding.mp4")
+	defer os.Remove(outPath)
+	if err := TranscodeFile(ctx, w.cfg.FFmpegPath, info, localPath, outPath); err != nil {
+		return err
+	}
+	stat, err := os.Stat(outPath)
+	if err != nil {
+		return fmt.Errorf("stat transcoded output: %w", err)
+	}
+
+	dirID, err := w.ensureTargetDir(ctx)
+	if err != nil {
+		return fmt.Errorf("ensure target dir: %w", err)
+	}
+	f, err := os.Open(outPath)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	fileID, err := w.drv.Upload(ctx, dirID, transcodedName(v), f, stat.Size())
+	if err != nil {
+		return fmt.Errorf("upload transcoded file: %w", err)
+	}
+	log.Printf("[transcode] drive=%s video=%s ready: file=%s size=%d", w.drv.ID(), v.ID, fileID, stat.Size())
+	return w.cat.UpdateVideoTranscode(ctx, v.ID, "ready", "", fileID, stat.Size())
+}
+
+// fetchSource 把原始文件准备成本地路径。本地存储直接复用源路径（cleanup
+// 不删除源文件）；云盘则整文件下载到 WorkDir。
+func (w *Worker) fetchSource(ctx context.Context, v *catalog.Video) (string, func(), error) {
+	link, err := w.drv.StreamURL(ctx, v.FileID)
+	if err != nil {
+		return "", nil, err
+	}
+	u, err := url.Parse(link.URL)
+	if isLocal := err == nil && u.Scheme != "http" && u.Scheme != "https"; isLocal {
+		path := link.URL
+		if err == nil && u.Scheme == "file" {
+			path = u.Path
+		}
+		return path, func() {}, nil
+	}
+
+	tmpPath := filepath.Join(w.cfg.WorkDir, sanitizeFileName(v.ID)+".src.tmp")
+	cleanup := func() { os.Remove(tmpPath) }
+	if err := w.downloadTo(ctx, link, tmpPath); err != nil {
+		cleanup()
+		return "", nil, err
+	}
+	return tmpPath, cleanup, nil
+}
+
+func (w *Worker) downloadTo(ctx context.Context, link *drives.StreamLink, dst string) error {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, link.URL, nil)
+	if err != nil {
+		return err
+	}
+	for k, vals := range link.Headers {
+		for _, val := range vals {
+			req.Header.Add(k, val)
+		}
+	}
+	res, err := w.hc.Do(req)
+	if err != nil {
+		return err
+	}
+	defer res.Body.Close()
+	if res.StatusCode < 200 || res.StatusCode >= 300 {
+		return fmt.Errorf("download source: HTTP %d", res.StatusCode)
+	}
+	f, err := os.Create(dst)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	if _, err := io.Copy(f, res.Body); err != nil {
+		return fmt.Errorf("download source: %w", err)
+	}
+	return f.Sync()
+}
+
+// ensureTargetDir 确保网盘上的转码产物目录存在，并把它写进 drive 的扫描
+// 跳过列表（幂等），避免 scanner 把产物再当新视频收进库。
+func (w *Worker) ensureTargetDir(ctx context.Context) (string, error) {
+	w.targetDirOnce.Do(func() {
+		dirID, err := w.drv.EnsureDir(ctx, w.cfg.TargetDirName)
+		if err != nil {
+			w.targetDirErr = err
+			return
+		}
+		w.targetDirID = dirID
+		if err := w.addDirToSkipList(ctx, dirID); err != nil {
+			// 跳过列表更新失败不阻塞转码，只记日志（最坏情况是 scanner
+			// 之后把产物扫成新视频，可手动加跳过目录修复）。
+			log.Printf("[transcode] drive=%s add skip dir %s: %v", w.drv.ID(), dirID, err)
+		}
+	})
+	return w.targetDirID, w.targetDirErr
+}
+
+func (w *Worker) addDirToSkipList(ctx context.Context, dirID string) error {
+	d, err := w.cat.GetDrive(ctx, w.drv.ID())
+	if err != nil {
+		return err
+	}
+	for _, existing := range d.SkipDirIDs {
+		if existing == dirID {
+			return nil
+		}
+	}
+	return w.cat.SetDriveSkipDirIDs(ctx, w.drv.ID(), append(d.SkipDirIDs, dirID))
+}
+
+// transcodedName 生成产物文件名：原文件名去掉扩展名 + .mp4。
+func transcodedName(v *catalog.Video) string {
+	base := strings.TrimSpace(v.FileName)
+	if base == "" {
+		base = v.Title
+	}
+	if base == "" {
+		base = v.ID
+	}
+	if ext := filepath.Ext(base); ext != "" {
+		base = strings.TrimSuffix(base, ext)
+	}
+	return sanitizeFileName(base) + ".mp4"
+}
+
+// sanitizeFileName 把路径分隔符等危险字符替换掉，避免拼出意外路径。
+func sanitizeFileName(name string) string {
+	replacer := strings.NewReplacer(
+		"/", "_", "\\", "_", ":", "_", "*", "_", "?", "_",
+		"\"", "_", "<", "_", ">", "_", "|", "_", "\x00", "_",
+	)
+	out := strings.TrimSpace(replacer.Replace(name))
+	if out == "" {
+		out = fmt.Sprintf("transcoded-%d", time.Now().UnixMilli())
+	}
+	return out
+}

src/admin/DrivesPage.tsx

@@ -48,6 +48,7 @@ function isDriveBusy(d: api.AdminDrive) {
     d.thumbnailGenerationStatus,
     d.previewGenerationStatus,
     d.fingerprintGenerationStatus,
+    d.transcodeGenerationStatus,
   ].some((status) => {
     const state = status?.state || "idle";
     return state !== "idle";
@@ -74,6 +75,7 @@ export function DrivesPage() {
   const [regenFailedThumbId, setRegenFailedThumbId] = useState("");
   const [regenFailedFingerprintId, setRegenFailedFingerprintId] = useState("");
   const [togglingTeaserId, setTogglingTeaserId] = useState("");
+  const [togglingTranscodeId, setTogglingTranscodeId] = useState("");
   const [scanningAll, setScanningAll] = useState(false);
   const [stoppingAll, setStoppingAll] = useState(false);
   const [trackingNightly, setTrackingNightly] = useState(false);
@@ -499,6 +501,41 @@ export function DrivesPage() {
     }
   }
 
+  async function handleStartTranscode(d: api.AdminDrive) {
+    setTogglingTranscodeId(d.id);
+    try {
+      const resp = await api.startDriveTranscode(d.id);
+      if (resp.accepted) {
+        show(`已开始「${d.name || d.id}」的视频转码`, "success");
+      } else {
+        show(resp.message || "转码任务未能开启", "info");
+      }
+      refreshDriveList();
+    } catch (e) {
+      show(e instanceof Error ? e.message : "开启失败", "error");
+    } finally {
+      setTogglingTranscodeId("");
+    }
+  }
+
+  async function handleStopTranscode(d: api.AdminDrive) {
+    setTogglingTranscodeId(d.id);
+    try {
+      const resp = await api.stopDriveTranscode(d.id);
+      show(
+        resp.stopped
+          ? `已停止「${d.name || d.id}」的视频转码`
+          : `「${d.name || d.id}」没有正在运行的转码任务`,
+        "success"
+      );
+      refreshDriveList();
+    } catch (e) {
+      show(e instanceof Error ? e.message : "停止失败", "error");
+    } finally {
+      setTogglingTranscodeId("");
+    }
+  }
+
   const selectedDrive = useMemo(() => {
     return selectedDriveId ? list.find((d) => d.id === selectedDriveId) : null;
   }, [selectedDriveId, list]);
@@ -634,10 +671,13 @@ export function DrivesPage() {
               regenFailedThumbId={regenFailedThumbId}
               regenFailedFingerprintId={regenFailedFingerprintId}
               togglingTeaserId={togglingTeaserId}
+              togglingTranscodeId={togglingTranscodeId}
               onToggleTeaser={() => handleToggleTeaser(d)}
               onRegenFailed={() => handleRegenFailed(d)}
               onRegenFailedThumbnails={() => handleRegenFailedThumbnails(d)}
               onRegenFailedFingerprints={() => handleRegenFailedFingerprints(d)}
+              onStartTranscode={() => handleStartTranscode(d)}
+              onStopTranscode={() => handleStopTranscode(d)}
             />
 
             <div className="admin-detail-card">

src/admin/api.ts

@@ -112,6 +112,12 @@ export type AdminDrive = {
   fingerprintReadyCount: number;
   fingerprintPendingCount: number;
   fingerprintFailedCount: number;
+  // 浏览器兼容性转码：候选(待处理)/已转码/失败/检测后无需转码 计数与任务状态。
+  transcodeGenerationStatus?: DriveGenerationStatus;
+  transcodePendingCount: number;
+  transcodeReadyCount: number;
+  transcodeFailedCount: number;
+  transcodeSkippedCount: number;
 };
 
 export type DriveGenerationStatus = {
@@ -449,6 +455,26 @@ export function regenFailedFingerprints(id: string) {
   );
 }
 
+/**
+ * 手动开启某存储的浏览器兼容性转码（AVI/WMV 等浏览器播不动的视频转 H.264 MP4，
+ * 产物上传回同一存储）。转码默认关闭、从不自动运行，这是唯一入口；
+ * 任务处理完候选列表后自然结束。
+ */
+export function startDriveTranscode(id: string) {
+  return request<{ ok: boolean; accepted: boolean; message?: string }>(
+    `/drives/${encodeURIComponent(id)}/transcode/start`,
+    { method: "POST" }
+  );
+}
+
+/** 手动停止某存储正在进行的转码任务。 */
+export function stopDriveTranscode(id: string) {
+  return request<{ ok: boolean; stopped: boolean }>(
+    `/drives/${encodeURIComponent(id)}/transcode/stop`,
+    { method: "POST" }
+  );
+}
+
 // ---------- Videos ----------
 
 export type AdminVideo = {

src/admin/drive/DriveComponents.tsx

@@ -1,4 +1,4 @@
-import { PlayCircle, Power, PowerOff, RotateCcw } from "lucide-react";
+import { CircleStop, PlayCircle, Power, PowerOff, RotateCcw, Wand2 } from "lucide-react";
 import * as api from "../api";
 import { formatBytes } from "../storageFormat";
 import {
@@ -163,20 +163,26 @@ export function DriveGenerationPanel({
   regenFailedThumbId,
   regenFailedFingerprintId,
   togglingTeaserId,
+  togglingTranscodeId,
   onToggleTeaser,
   onRegenFailed,
   onRegenFailedThumbnails,
   onRegenFailedFingerprints,
+  onStartTranscode,
+  onStopTranscode,
 }: {
   d: api.AdminDrive;
   regenFailedId: string;
   regenFailedThumbId: string;
   regenFailedFingerprintId: string;
   togglingTeaserId: string;
+  togglingTranscodeId: string;
   onToggleTeaser: () => void;
   onRegenFailed: () => void;
   onRegenFailedThumbnails: () => void;
   onRegenFailedFingerprints: () => void;
+  onStartTranscode: () => void;
+  onStopTranscode: () => void;
 }) {
   const canQueueThumbnails =
     (d.thumbnailFailedCount ?? 0) > 0 ||
@@ -186,6 +192,12 @@ export function DriveGenerationPanel({
     (d.teaserFailedCount ?? 0) > 0 || (d.teaserPendingCount ?? 0) > 0;
   const canQueueFingerprints =
     (d.fingerprintFailedCount ?? 0) > 0 || (d.fingerprintPendingCount ?? 0) > 0;
+  // 转码默认不运行，只能在这里手动开启/停止。
+  // 候选 = 还没出结果的不兼容格式视频 + 上次失败的（重新开始会自动重试）。
+  const transcodeRunning =
+    (d.transcodeGenerationStatus?.state || "idle") !== "idle";
+  const canStartTranscode =
+    (d.transcodePendingCount ?? 0) > 0 || (d.transcodeFailedCount ?? 0) > 0;
 
   return (
     <div className="admin-detail-card">
@@ -235,6 +247,13 @@ export function DriveGenerationPanel({
           pending={d.fingerprintPendingCount}
           failed={d.fingerprintFailedCount}
         />
+        <DriveGenCol
+          label="转码"
+          status={d.transcodeGenerationStatus}
+          ready={d.transcodeReadyCount}
+          pending={d.transcodePendingCount}
+          failed={d.transcodeFailedCount}
+        />
       </div>
 
       <div className="admin-detail-actions">
@@ -262,6 +281,33 @@ export function DriveGenerationPanel({
           <RotateCcw size={13} />
           <span>{(d.fingerprintFailedCount ?? 0) > 0 ? "重试失败指纹" : "继续生成指纹"}</span>
         </button>
+        {transcodeRunning ? (
+          <button
+            className="admin-btn is-stop"
+            disabled={togglingTranscodeId === d.id}
+            onClick={onStopTranscode}
+            title="停止当前的转码任务。未处理的视频保持原状态，下次开始时继续。"
+          >
+            <CircleStop size={13} />
+            <span>{togglingTranscodeId === d.id ? "停止中..." : "停止转码"}</span>
+          </button>
+        ) : (
+          <button
+            className="admin-btn"
+            disabled={!canStartTranscode || togglingTranscodeId === d.id}
+            onClick={onStartTranscode}
+            title="把浏览器播放不了的视频（AVI/WMV/RMVB、MPEG-4 等老格式）转码成 H.264 MP4 并上传回本存储。转码不会自动运行，只能在这里手动开启。"
+          >
+            <Wand2 size={13} />
+            <span>
+              {togglingTranscodeId === d.id
+                ? "开启中..."
+                : (d.transcodeFailedCount ?? 0) > 0 && (d.transcodePendingCount ?? 0) === 0
+                ? "重试失败转码"
+                : "开始转码"}
+            </span>
+          </button>
+        )}
       </div>
     </div>
   );