diff --git a/src/components/video-editor/CropControl.tsx b/src/components/video-editor/CropControl.tsx
index 036116c..401c4d5 100644
--- a/src/components/video-editor/CropControl.tsx
+++ b/src/components/video-editor/CropControl.tsx
@@ -1,5 +1,6 @@
 import { useEffect, useRef, useState } from "react";
 import { cn } from "@/lib/utils";
+import { type AspectRatio, formatAspectRatioForCSS } from "@/utils/aspectRatioUtils";
 
 interface CropRegion {
   x: number; // 0-1 normalized
@@ -12,11 +13,12 @@ interface CropControlProps {
   videoElement: HTMLVideoElement | null;
   cropRegion: CropRegion;
   onCropChange: (region: CropRegion) => void;
+  aspectRatio: AspectRatio;
 }
 
 type DragHandle = 'top' | 'right' | 'bottom' | 'left' | null;
 
-export function CropControl({ videoElement, cropRegion, onCropChange }: CropControlProps) {
+export function CropControl({ videoElement, cropRegion, onCropChange, aspectRatio }: CropControlProps) {
   const canvasRef = useRef<HTMLCanvasElement>(null);
   const containerRef = useRef<HTMLDivElement>(null);
   const [isDragging, setIsDragging] = useState<DragHandle>(null);
@@ -114,12 +116,22 @@ export function CropControl({ videoElement, cropRegion, onCropChange }: CropCont
   const cropPixelY = cropRegion.y * 100;
   const cropPixelWidth = cropRegion.width * 100;
   const cropPixelHeight = cropRegion.height * 100;
+  const videoAspectRatio = videoElement ? videoElement.videoWidth / videoElement.videoHeight : 16/9;
+  const isVideoPortrait = videoAspectRatio < 1;
+  const maxContainerWidth = isVideoPortrait ? '40vw' : '75vw';
+  const maxContainerHeight = '75vh';
 
   return (
     <div className="w-full p-8">
       <div
         ref={containerRef}
-        className="relative w-full aspect-video bg-black rounded-lg overflow-visible cursor-default select-none shadow-2xl"
+        className="relative w-full bg-black rounded-lg overflow-visible cursor-default select-none shadow-2xl"
+        style={{ 
+          aspectRatio: videoAspectRatio,
+          maxWidth: maxContainerWidth,
+          maxHeight: maxContainerHeight,
+          margin: '0 auto',
+        }}
         onPointerMove={handlePointerMove}
         onPointerUp={handlePointerUp}
         onPointerLeave={handlePointerUp}
diff --git a/src/components/video-editor/SettingsPanel.tsx b/src/components/video-editor/SettingsPanel.tsx
index e378cab..982d71a 100644
--- a/src/components/video-editor/SettingsPanel.tsx
+++ b/src/components/video-editor/SettingsPanel.tsx
@@ -14,6 +14,7 @@ import { toast } from "sonner";
 import type { ZoomDepth, CropRegion } from "./types";
 import { CropControl } from "./CropControl";
 import { KeyboardShortcutsHelp } from "./KeyboardShortcutsHelp";
+import { type AspectRatio } from "@/utils/aspectRatioUtils";
 
 const WALLPAPER_COUNT = 18;
 const WALLPAPER_RELATIVE = Array.from({ length: WALLPAPER_COUNT }, (_, i) => `wallpapers/wallpaper${i + 1}.jpg`);
@@ -63,6 +64,7 @@ interface SettingsPanelProps {
   onPaddingChange?: (padding: number) => void;
   cropRegion?: CropRegion;
   onCropChange?: (region: CropRegion) => void;
+  aspectRatio: AspectRatio;
   videoElement?: HTMLVideoElement | null;
   onExport?: () => void;
 }
@@ -78,7 +80,7 @@ const ZOOM_DEPTH_OPTIONS: Array<{ depth: ZoomDepth; label: string }> = [
   { depth: 6, label: "5×" },
 ];
 
-export function SettingsPanel({ selected, onWallpaperChange, selectedZoomDepth, onZoomDepthChange, selectedZoomId, onZoomDelete, shadowIntensity = 0, onShadowChange, showBlur, onBlurChange, motionBlurEnabled = true, onMotionBlurChange, borderRadius = 0, onBorderRadiusChange, padding = 50, onPaddingChange, cropRegion, onCropChange, videoElement, onExport }: SettingsPanelProps) {
+export function SettingsPanel({ selected, onWallpaperChange, selectedZoomDepth, onZoomDepthChange, selectedZoomId, onZoomDelete, shadowIntensity = 0, onShadowChange, showBlur, onBlurChange, motionBlurEnabled = true, onMotionBlurChange, borderRadius = 0, onBorderRadiusChange, padding = 50, onPaddingChange, cropRegion, onCropChange, aspectRatio, videoElement, onExport }: SettingsPanelProps) {
   const [wallpaperPaths, setWallpaperPaths] = useState<string[]>([]);
   const [customImages, setCustomImages] = useState<string[]>([]);
   const fileInputRef = useRef<HTMLInputElement>(null);
@@ -300,7 +302,7 @@ export function SettingsPanel({ selected, onWallpaperChange, selectedZoomDepth,
             className="fixed inset-0 bg-black/80 backdrop-blur-sm z-50 animate-in fade-in duration-200"
             onClick={() => setShowCropDropdown(false)}
           />
-          <div className="fixed top-1/2 left-1/2 transform -translate-x-1/2 -translate-y-1/2 z-[60] bg-[#09090b] rounded-2xl shadow-2xl border border-white/10 p-8 w-[90vw] max-w-5xl animate-in zoom-in-95 duration-200">
+          <div className="fixed top-1/2 left-1/2 transform -translate-x-1/2 -translate-y-1/2 z-[60] bg-[#09090b] rounded-2xl shadow-2xl border border-white/10 p-8 w-[90vw] max-w-5xl max-h-[90vh] overflow-auto animate-in zoom-in-95 duration-200">
             <div className="flex items-center justify-between mb-6">
               <div>
                 <span className="text-xl font-bold text-slate-200">Crop Video</span>
@@ -319,6 +321,7 @@ export function SettingsPanel({ selected, onWallpaperChange, selectedZoomDepth,
               videoElement={videoElement || null}
               cropRegion={cropRegion}
               onCropChange={onCropChange}
+              aspectRatio={aspectRatio}
             />
             <div className="mt-6 flex justify-end">
               <Button
diff --git a/src/components/video-editor/VideoEditor.tsx b/src/components/video-editor/VideoEditor.tsx
index a4506e6..847f932 100644
--- a/src/components/video-editor/VideoEditor.tsx
+++ b/src/components/video-editor/VideoEditor.tsx
@@ -23,6 +23,7 @@ import {
   type CropRegion,
 } from "./types";
 import { VideoExporter, type ExportProgress } from "@/lib/exporter";
+import { type AspectRatio, getAspectRatioValue } from "@/utils/aspectRatioUtils";
 
 const WALLPAPER_COUNT = 18;
 const WALLPAPER_PATHS = Array.from({ length: WALLPAPER_COUNT }, (_, i) => `/wallpapers/wallpaper${i + 1}.jpg`);
@@ -49,6 +50,7 @@ export default function VideoEditor() {
   const [exportProgress, setExportProgress] = useState<ExportProgress | null>(null);
   const [exportError, setExportError] = useState<string | null>(null);
   const [showExportDialog, setShowExportDialog] = useState(false);
+  const [aspectRatio, setAspectRatio] = useState<AspectRatio>('16:9');
 
   const videoPlaybackRef = useRef<VideoPlaybackRef>(null);
   const nextZoomIdRef = useRef(1);
@@ -263,24 +265,53 @@ export default function VideoEditor() {
         return;
       }
       
+      const aspectRatioValue = getAspectRatioValue(aspectRatio);
       const sourceWidth = video.videoWidth || 1920;
       const sourceHeight = video.videoHeight || 1080;
-      const targetAspectRatio = 16 / 9;
-      const sourceAspectRatio = sourceWidth / sourceHeight;
       
-      let exportWidth: number;
-      let exportHeight: number;
-      
-      if (sourceAspectRatio > targetAspectRatio) {
-        exportHeight = sourceHeight;
-        exportWidth = Math.round(exportHeight * targetAspectRatio);
+      let exportWidth: number = sourceWidth;
+      let exportHeight: number = sourceHeight;
+
+      if (aspectRatioValue === 1) {
+        // Square (1:1): use smaller dimension to avoid codec limits
+        const baseDimension = Math.floor(Math.min(sourceWidth, sourceHeight) / 2) * 2;
+        exportWidth = baseDimension;
+        exportHeight = baseDimension;
+      } else if (aspectRatioValue > 1) {
+        // Landscape: find largest even dimensions that exactly match aspect ratio
+        const baseWidth = Math.floor(sourceWidth / 2) * 2;
+        // Iterate down from baseWidth to find exact match
+        let found = false;
+        for (let w = baseWidth; w >= 100 && !found; w -= 2) {
+          const h = Math.round(w / aspectRatioValue);
+          if (h % 2 === 0 && Math.abs((w / h) - aspectRatioValue) < 0.0001) {
+            exportWidth = w;
+            exportHeight = h;
+            found = true;
+          }
+        }
+        if (!found) {
+          exportWidth = baseWidth;
+          exportHeight = Math.floor((baseWidth / aspectRatioValue) / 2) * 2;
+        }
       } else {
-        exportWidth = sourceWidth;
-        exportHeight = Math.round(exportWidth / targetAspectRatio);
+        // Portrait: find largest even dimensions that exactly match aspect ratio
+        const baseHeight = Math.floor(sourceHeight / 2) * 2;
+        // Iterate down from baseHeight to find exact match
+        let found = false;
+        for (let h = baseHeight; h >= 100 && !found; h -= 2) {
+          const w = Math.round(h * aspectRatioValue);
+          if (w % 2 === 0 && Math.abs((w / h) - aspectRatioValue) < 0.0001) {
+            exportWidth = w;
+            exportHeight = h;
+            found = true;
+          }
+        }
+        if (!found) {
+          exportHeight = baseHeight;
+          exportWidth = Math.floor((baseHeight * aspectRatioValue) / 2) * 2;
+        }
       }
-      
-      exportWidth = Math.round(exportWidth / 2) * 2;
-      exportHeight = Math.round(exportHeight / 2) * 2;
 
       // Calculate visually lossless bitrate matching screen recording optimization
       const totalPixels = exportWidth * exportHeight;
@@ -348,7 +379,7 @@ export default function VideoEditor() {
       setIsExporting(false);
       exporterRef.current = null;
     }
-  }, [videoPath, wallpaper, zoomRegions, trimRegions, shadowIntensity, showBlur, motionBlurEnabled, borderRadius, padding, cropRegion, isPlaying]);
+  }, [videoPath, wallpaper, zoomRegions, trimRegions, shadowIntensity, showBlur, motionBlurEnabled, borderRadius, padding, cropRegion, isPlaying, aspectRatio]);
 
   const handleCancelExport = useCallback(() => {
     if (exporterRef.current) {
@@ -395,8 +426,9 @@ export default function VideoEditor() {
               <div className="w-full h-full flex flex-col items-center justify-center bg-black/40 rounded-2xl border border-white/5 shadow-2xl overflow-hidden">
                 {/* Video preview */}
                 <div className="w-full flex justify-center items-center" style={{ flex: '1 1 auto', margin: '6px 0 0' }}>
-                  <div className="relative" style={{ width: 'auto', height: '100%', aspectRatio: '16/9', maxWidth: '100%', margin: '0 auto', boxSizing: 'border-box' }}>
+                  <div className="relative" style={{ width: 'auto', height: '100%', aspectRatio: getAspectRatioValue(aspectRatio), maxWidth: '100%', margin: '0 auto', boxSizing: 'border-box' }}>
                     <VideoPlayback
+                      aspectRatio={aspectRatio}
                       ref={videoPlaybackRef}
                       videoPath={videoPath || ''}
                       onDurationChange={setDuration}
@@ -443,22 +475,24 @@ export default function VideoEditor() {
             <Panel defaultSize={30} minSize={20}>
               <div className="h-full bg-[#09090b] rounded-2xl border border-white/5 shadow-lg overflow-hidden flex flex-col">
                 <TimelineEditor
-                  videoDuration={duration}
-                  currentTime={currentTime}
-                  onSeek={handleSeek}
-                  zoomRegions={zoomRegions}
-                  onZoomAdded={handleZoomAdded}
-                  onZoomSpanChange={handleZoomSpanChange}
-                  onZoomDelete={handleZoomDelete}
-                  selectedZoomId={selectedZoomId}
-                  onSelectZoom={handleSelectZoom}
-                  trimRegions={trimRegions}
-                  onTrimAdded={handleTrimAdded}
-                  onTrimSpanChange={handleTrimSpanChange}
-                  onTrimDelete={handleTrimDelete}
-                  selectedTrimId={selectedTrimId}
-                  onSelectTrim={handleSelectTrim}
-                />
+              videoDuration={duration}
+              currentTime={currentTime}
+              onSeek={handleSeek}
+              zoomRegions={zoomRegions}
+              onZoomAdded={handleZoomAdded}
+              onZoomSpanChange={handleZoomSpanChange}
+              onZoomDelete={handleZoomDelete}
+              selectedZoomId={selectedZoomId}
+              onSelectZoom={handleSelectZoom}
+              trimRegions={trimRegions}
+              onTrimAdded={handleTrimAdded}
+              onTrimSpanChange={handleTrimSpanChange}
+              onTrimDelete={handleTrimDelete}
+              selectedTrimId={selectedTrimId}
+              onSelectTrim={handleSelectTrim}
+              aspectRatio={aspectRatio}
+              onAspectRatioChange={setAspectRatio}
+            />
               </div>
             </Panel>
           </PanelGroup>
@@ -484,6 +518,7 @@ export default function VideoEditor() {
           onPaddingChange={setPadding}
           cropRegion={cropRegion}
           onCropChange={setCropRegion}
+          aspectRatio={aspectRatio}
           videoElement={videoPlaybackRef.current?.video || null}
           onExport={handleExport}
         />
diff --git a/src/components/video-editor/VideoPlayback.tsx b/src/components/video-editor/VideoPlayback.tsx
index 905e37f..8656dfb 100644
--- a/src/components/video-editor/VideoPlayback.tsx
+++ b/src/components/video-editor/VideoPlayback.tsx
@@ -11,6 +11,7 @@ import { updateOverlayIndicator } from "./videoPlayback/overlayUtils";
 import { layoutVideoContent as layoutVideoContentUtil } from "./videoPlayback/layoutUtils";
 import { applyZoomTransform } from "./videoPlayback/zoomTransform";
 import { createVideoEventHandlers } from "./videoPlayback/videoEventHandlers";
+import { type AspectRatio, formatAspectRatioForCSS } from "@/utils/aspectRatioUtils";
 
 interface VideoPlaybackProps {
   videoPath: string;
@@ -32,6 +33,7 @@ interface VideoPlaybackProps {
   padding?: number;
   cropRegion?: import('./types').CropRegion;
   trimRegions?: TrimRegion[];
+  aspectRatio: AspectRatio;
 }
 
 export interface VideoPlaybackRef {
@@ -63,6 +65,7 @@ const VideoPlayback = forwardRef<VideoPlaybackRef, VideoPlaybackProps>(({
   padding = 50,
   cropRegion,
   trimRegions = [],
+  aspectRatio,
 }, ref) => {
   const videoRef = useRef<HTMLVideoElement | null>(null);
   const containerRef = useRef<HTMLDivElement | null>(null);
@@ -747,7 +750,7 @@ const VideoPlayback = forwardRef<VideoPlaybackRef, VideoPlaybackProps>(({
     : { background: resolvedWallpaper || '' };
 
   return (
-    <div className="relative aspect-video rounded-sm overflow-hidden" style={{ width: '100%' }}>
+    <div className="relative rounded-sm overflow-hidden" style={{ width: '100%', aspectRatio: formatAspectRatioForCSS(aspectRatio) }}>
       {/* Background layer - always render as DOM element with blur */}
       <div
         className="absolute inset-0 bg-cover bg-center"
diff --git a/src/components/video-editor/timeline/TimelineEditor.tsx b/src/components/video-editor/timeline/TimelineEditor.tsx
index 14688ab..907081d 100644
--- a/src/components/video-editor/timeline/TimelineEditor.tsx
+++ b/src/components/video-editor/timeline/TimelineEditor.tsx
@@ -1,7 +1,7 @@
 import { useCallback, useEffect, useMemo, useState } from "react";
 import { useTimelineContext } from "dnd-timeline";
 import { Button } from "@/components/ui/button";
-import { Plus, Scissors, ZoomIn } from "lucide-react";
+import { Plus, Scissors, ZoomIn, ChevronDown, Check } from "lucide-react";
 import { toast } from "sonner";
 import { cn } from "@/lib/utils";
 import TimelineWrapper from "./TimelineWrapper";
@@ -11,6 +11,13 @@ import KeyframeMarkers from "./KeyframeMarkers";
 import type { Range, Span } from "dnd-timeline";
 import type { ZoomRegion, TrimRegion } from "../types";
 import { v4 as uuidv4 } from 'uuid';
+import {
+  DropdownMenu,
+  DropdownMenuContent,
+  DropdownMenuItem,
+  DropdownMenuTrigger,
+} from "@/components/ui/dropdown-menu";
+import { type AspectRatio, getAspectRatioLabel } from "@/utils/aspectRatioUtils";
 
 const ZOOM_ROW_ID = "row-zoom";
 const TRIM_ROW_ID = "row-trim";
@@ -34,6 +41,8 @@ interface TimelineEditorProps {
   onTrimDelete?: (id: string) => void;
   selectedTrimId?: string | null;
   onSelectTrim?: (id: string | null) => void;
+  aspectRatio: AspectRatio;
+  onAspectRatioChange: (aspectRatio: AspectRatio) => void;
 }
 
 interface TimelineScaleConfig {
@@ -410,6 +419,8 @@ export default function TimelineEditor({
   onTrimDelete,
   selectedTrimId,
   onSelectTrim,
+  aspectRatio,
+  onAspectRatioChange,
 }: TimelineEditorProps) {
   const totalMs = useMemo(() => Math.max(0, Math.round(videoDuration * 1000)), [videoDuration]);
   const currentTimeMs = useMemo(() => Math.round(currentTime * 1000), [currentTime]);
@@ -683,6 +694,32 @@ export default function TimelineEditor({
             <Scissors className="w-4 h-4" />
           </Button>
         </div>
+        <div className="flex items-center gap-2">
+          <DropdownMenu>
+            <DropdownMenuTrigger asChild>
+              <Button
+                variant="ghost"
+                size="sm"
+                className="h-7 px-2 text-xs text-slate-400 hover:text-slate-200 hover:bg-white/10 transition-all gap-1"
+              >
+                <span className="font-medium">{getAspectRatioLabel(aspectRatio)}</span>
+                <ChevronDown className="w-3 h-3" />
+              </Button>
+            </DropdownMenuTrigger>
+            <DropdownMenuContent align="end" className="bg-[#1a1a1a] border-white/10">
+              {(['16:9', '9:16', '1:1', '4:3', '4:5'] as AspectRatio[]).map((ratio) => (
+                <DropdownMenuItem
+                  key={ratio}
+                  onClick={() => onAspectRatioChange(ratio)}
+                  className="text-slate-300 hover:text-white hover:bg-white/10 cursor-pointer flex items-center justify-between gap-3"
+                >
+                  <span>{getAspectRatioLabel(ratio)}</span>
+                  {aspectRatio === ratio && <Check className="w-3 h-3 text-[#34B27B]" />}
+                </DropdownMenuItem>
+              ))}
+            </DropdownMenuContent>
+          </DropdownMenu>
+        </div>
         <div className="flex-1" />
         <div className="flex items-center gap-4 text-[10px] text-slate-500 font-medium">
           <span className="flex items-center gap-1.5">
diff --git a/src/utils/aspectRatioUtils.ts b/src/utils/aspectRatioUtils.ts
new file mode 100644
index 0000000..aaad804
--- /dev/null
+++ b/src/utils/aspectRatioUtils.ts
@@ -0,0 +1,31 @@
+export type AspectRatio = '16:9' | '9:16' | '1:1' | '4:3' | '4:5';
+
+export function getAspectRatioValue(aspectRatio: AspectRatio): number {
+  switch (aspectRatio) {
+    case '16:9': return 16 / 9;
+    case '9:16': return 9 / 16;
+    case '1:1':  return 1;
+    case '4:3':  return 4 / 3;
+    case '4:5':  return 4 / 5;
+  }
+}
+
+export function getAspectRatioDimensions(
+  aspectRatio: AspectRatio,
+  baseWidth: number
+): { width: number; height: number } {
+  const ratio = getAspectRatioValue(aspectRatio);
+  return {
+    width: baseWidth,
+    height: baseWidth / ratio,
+  };
+}
+
+export function getAspectRatioLabel(aspectRatio: AspectRatio): string {
+  return aspectRatio;
+}
+
+
+export function formatAspectRatioForCSS(aspectRatio: AspectRatio): string {
+  return aspectRatio.replace(':', '/');
+}
\ No newline at end of file