diff --git a/package.json b/package.json
index 67fe05f..7ccde2f 100644
--- a/package.json
+++ b/package.json
@@ -26,6 +26,7 @@
     "test:skill-install": "node scripts/test-skill-install-instruction.cjs",
     "cp:env": "node scripts/ensure-env.cjs",
     "prepare:env": "node scripts/ensure-env.cjs",
+    "prepare:ffmpeg:win": "node scripts/prepare-electron-runtime.cjs --platform win32 --arch x64",
     "start": "electron-vite preview",
     "dev": "node scripts/ensure-env.cjs && node scripts/build-wechat-connector.cjs && electron-vite dev",
     "test:wechat-connector": "go -C services/wechat-connector test ./... && go -C services/wechat-connector vet ./...",
@@ -43,12 +44,12 @@
     "build": "npm run typecheck && npm run build:native-services && electron-vite build",
     "postinstall": "electron-builder install-app-deps && node scripts/prepare-electron-runtime.cjs",
     "build:unpack": "npm run build && electron-builder --config electron-builder.yml --dir",
-    "build:win": "npm run typecheck && npm run build:wechat-connector:win && electron-vite build && electron-builder --config electron-builder.yml --win --x64",
+    "build:win": "npm run typecheck && npm run build:wechat-connector:win && npm run prepare:ffmpeg:win && electron-vite build && electron-builder --config electron-builder.yml --win --x64",
     "build:mac:x64": "npm run typecheck && node scripts/build-wechat-connector.cjs --platform darwin --arch x64 && electron-vite build && electron-builder --config electron-builder.yml --mac --x64",
     "build:mac:arm64": "npm run typecheck && node scripts/build-wechat-connector.cjs --platform darwin --arch arm64 && electron-vite build && electron-builder --config electron-builder.yml --mac --arm64",
     "release": "npm run release:mac && npm run release:win",
     "release:mac": "npm run typecheck && npm run build:wechat-connector:mac && electron-vite build && electron-builder --config electron-builder.yml --mac --x64 --arm64 --publish always",
-    "release:win": "npm run typecheck && npm run build:wechat-connector:win && electron-vite build && electron-builder --config electron-builder.yml --win --x64 --publish always",
+    "release:win": "npm run typecheck && npm run build:wechat-connector:win && npm run prepare:ffmpeg:win && electron-vite build && electron-builder --config electron-builder.yml --win --x64 --publish always",
     "release:beta": "cross-env RELEASE_TYPE=prerelease npm run release",
     "release:stable": "cross-env RELEASE_TYPE=release npm run release",
     "build:linux": "electron-vite build && electron-builder --config electron-builder.yml --linux"
diff --git a/scripts/prepare-electron-runtime.cjs b/scripts/prepare-electron-runtime.cjs
index 221d6a7..cac6d0a 100644
--- a/scripts/prepare-electron-runtime.cjs
+++ b/scripts/prepare-electron-runtime.cjs
@@ -19,24 +19,49 @@ function copyIfDifferent(sourcePath, targetPath) {
   return true
 }
 
-function prepareFfmpegRuntime() {
-  let ffmpegPath = ''
+function readOption(name, fallback) {
+  const index = process.argv.indexOf(`--${name}`)
+  return index >= 0 && process.argv[index + 1] ? process.argv[index + 1] : fallback
+}
+
+function prepareFfmpegRuntime(targetPlatform = process.platform, targetArch = process.arch) {
+  let packageRoot = ''
   try {
-    ffmpegPath = require('ffmpeg-static') || ''
+    packageRoot = path.dirname(require.resolve('ffmpeg-static/package.json'))
   } catch {
     return
   }
-  if (!ffmpegPath || !fs.existsSync(ffmpegPath) || process.platform === 'win32') return
+  const executable = targetPlatform === 'win32' ? 'ffmpeg.exe' : 'ffmpeg'
+  const ffmpegPath = path.join(packageRoot, executable)
+
+  if (!fs.existsSync(ffmpegPath)) {
+    const installScript = path.join(packageRoot, 'install.js')
+    console.log(
+      `[prepare-electron-runtime] downloading ffmpeg-static for ${targetPlatform}-${targetArch}`
+    )
+    execFileSync(process.execPath, [installScript], {
+      stdio: 'inherit',
+      env: {
+        ...process.env,
+        npm_config_platform: targetPlatform,
+        npm_config_arch: targetArch
+      }
+    })
+  }
+
+  if (!fs.existsSync(ffmpegPath)) {
+    throw new Error(`ffmpeg-static runtime download failed: ${ffmpegPath}`)
+  }
+  if (targetPlatform === 'win32') return
+
   fs.chmodSync(ffmpegPath, 0o755)
   if (process.platform === 'darwin') {
-    execFileSync('/usr/bin/codesign', ['--force', '--sign', '-', ffmpegPath], {
-      stdio: 'ignore'
-    })
+    execFileSync('/usr/bin/codesign', ['--force', '--sign', '-', ffmpegPath], { stdio: 'ignore' })
   }
 }
 
 function main() {
-  prepareFfmpegRuntime()
+  prepareFfmpegRuntime(readOption('platform', process.platform), readOption('arch', process.arch))
   if (process.platform !== 'win32') return
 
   const projectRoot = path.resolve(__dirname, '..')