fix: Wails file drop, duplicate listeners, trim drag, crop stage, preview cache/pixfmt, NSIS temp quoting

internal/preview/server.go

@@ -22,6 +22,8 @@ import (
 type Server struct {
 	addr       string
 	httpSrv    *http.Server
+	ctx        context.Context
+	cancel     context.CancelFunc
 	ffmpegBin  string
 	mu         sync.RWMutex
 	files      map[string]registeredFile
@@ -41,8 +43,11 @@ func Start(ffmpegBin string) (*Server, error) {
 		return nil, err
 	}
 
+	ctx, cancel := context.WithCancel(context.Background())
 	s := &Server{
 		addr:       ln.Addr().String(),
+		ctx:        ctx,
+		cancel:     cancel,
 		ffmpegBin:  ffmpegBin,
 		files:      make(map[string]registeredFile),
 		proxyLocks: make(map[string]*sync.Mutex),
@@ -78,7 +83,12 @@ func (s *Server) BaseURL() string {
 }
 
 func (s *Server) Register(info *media.VideoInfo) string {
-	sum := sha1.Sum([]byte(info.Path))
+	var modUnix int64
+	if st, err := os.Stat(info.Path); err == nil {
+		modUnix = st.ModTime().UnixNano()
+	}
+	key := fmt.Sprintf("%s|%d|%d", info.Path, info.SizeBytes, modUnix)
+	sum := sha1.Sum([]byte(key))
 	id := hex.EncodeToString(sum[:8])
 
 	s.mu.Lock()
@@ -88,6 +98,9 @@ func (s *Server) Register(info *media.VideoInfo) string {
 }
 
 func (s *Server) Close() {
+	if s.cancel != nil {
+		s.cancel()
+	}
 	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
 	defer cancel()
 	if s.httpSrv != nil {
@@ -166,7 +179,7 @@ func (s *Server) handleProxy(w http.ResponseWriter, r *http.Request) {
 
 	if proxyPath == "" {
 		proxyPath = filepath.Join(os.TempDir(), fmt.Sprintf("convert_preview_%s.mp4", cacheKey))
-		if err := s.buildProxy(r.Context(), ffmpegBin, rf.info, merge, proxyPath); err != nil {
+		if err := s.buildProxy(s.ctx, ffmpegBin, rf.info, merge, proxyPath); err != nil {
 			http.Error(w, err.Error(), http.StatusInternalServerError)
 			return
 		}
@@ -211,8 +224,8 @@ func (s *Server) buildProxy(ctx context.Context, ffmpegBin string, info *media.V
 		args = append(args, "-map", "0:v:0", "-map", "0:a:0", "-c:a", "aac", "-b:a", "128k")
 	}
 
-	if info.VideoCodec == "h264" {
-		// Remux video stream instantaneously when codec is already H.264
+	if info.VideoCodec == "h264" && media.IsH264BrowserNativePixFmt(info.PixFmt) {
+		// Remux video stream instantaneously when codec is already browser-native 8-bit H.264
 		args = append(args, "-c:v", "copy")
 	} else {
 		args = append(args,
@@ -220,7 +233,7 @@ func (s *Server) buildProxy(ctx context.Context, ffmpegBin string, info *media.V
 			"-preset", "ultrafast",
 			"-crf", "26",
 			"-pix_fmt", "yuv420p",
-			"-vf", "scale='min(1280,iw)':-2",
+			"-vf", "scale='min(1280,trunc(iw/2)*2)':-2",
 		)
 	}
 	args = append(args, "-movflags", "+faststart", outPath)