Aspect ratio (#534)

* update

* update

* Create video2.mp4

* add art.quality

* fix art.theme

packages/artplayer/src/player/posterMix.js

@@ -2,14 +2,18 @@ import { def, setStyle } from '../utils';
 
 export default function posterMix(art) {
     const {
-        option,
         template: { $poster },
     } = art;
 
     def(art, 'poster', {
-        get: () => option.poster,
+        get: () => {
+            try {
+                return $poster.style['backgroundImage'].match(/"(.*)"/)[1];
+            } catch (error) {
+                return '';
+            }
+        },
         set(url) {
-            option.poster = url;
             setStyle($poster, 'backgroundImage', `url(${url})`);
         },
     });