diff --git a/packages/vmind/__tests__/browser/src/pages/ChartPreview.tsx b/packages/vmind/__tests__/browser/src/pages/ChartPreview.tsx
index 9e7a6432..49b862b4 100644
--- a/packages/vmind/__tests__/browser/src/pages/ChartPreview.tsx
+++ b/packages/vmind/__tests__/browser/src/pages/ChartPreview.tsx
@@ -61,7 +61,7 @@ export function ChartPreview(props: IPropsType) {
       log: true
     });
     await ffmpeg.load();
-    const src = await vmind.exportVideo(spec, time, {
+    const data = await vmind.exportVideo(spec, time, {
       VChart,
       FFmpeg: ffmpeg,
       fetchFile,
@@ -69,6 +69,7 @@ export function ChartPreview(props: IPropsType) {
       defaultTimeline,
       createCanvas
     } as any);
+    const src = URL.createObjectURL(new Blob([data], { type: 'video/mp4' }));
     setSrc(src);
     setOutType('video');
     setGenerating(false);
@@ -84,7 +85,7 @@ export function ChartPreview(props: IPropsType) {
       log: true
     });
     await ffmpeg.load();
-    const src = await vmind.exportGIF(spec, time, {
+    const data = await vmind.exportGIF(spec, time, {
       VChart,
       FFmpeg: ffmpeg,
       fetchFile,
@@ -92,6 +93,7 @@ export function ChartPreview(props: IPropsType) {
       defaultTimeline,
       createCanvas
     } as any);
+    const src = URL.createObjectURL(new Blob([data], { type: 'video/mp4' }));
     setSrc(src);
     setOutType('gif');
     setGenerating(false);
diff --git a/packages/vmind/src/core/VMind.ts b/packages/vmind/src/core/VMind.ts
index 44a89e82..eca79848 100644
--- a/packages/vmind/src/core/VMind.ts
+++ b/packages/vmind/src/core/VMind.ts
@@ -101,8 +101,7 @@ class VMind {
     const outName = `out`;
     await _chatToVideoWasm(this._FPS, spec, time, outName, outerPackages);
     const data = FFmpeg.FS('readFile', `${outName}.mp4`);
-    const objUrl = URL.createObjectURL(new Blob([data.buffer], { type: 'video/mp4' }));
-    return objUrl;
+    return data.buffer;
   }
 
   async exportGIF(spec: any, time: TimeType, outerPackages: OuterPackages) {
@@ -121,8 +120,7 @@ class VMind {
       'out.gif'
     );
     const data = FFmpeg.FS('readFile', 'out.gif');
-    const objUrl = URL.createObjectURL(new Blob([data.buffer], { type: 'video/mp4' }));
-    return objUrl;
+    return data.buffer;
   }
 }