auto show video snapshot

www/js/beauty.js

@@ -254,16 +254,23 @@ if ($('#pr-player').length > 0 && typeof(videojs) != 'undefined') {
             ctx.drawImage( video, 0, 0, canvas.width, canvas.height );
 
             var snapshotImg = canvas.toDataURL('image/jpeg');
+
+            //更新视频封面图和视频时长
+            $('#poster_'+mc_video_id).attr('src', snapshotImg);
+            $('#poster_'+mc_video_id).parent('a').find('.duration').text(formatDuration(myPlayer.duration()));
+
             saveVideoMeta(mc_video_id, {
                 duration: myPlayer.duration(),
                 snapshot: snapshotImg
             });
 
+            mc_video_id = null;
+
             tryToGetVideoSnapshot();    //go next
         }
     });
 
-    setInterval(tryToGetVideoSnapshot, 1000);
+    setInterval(tryToGetVideoSnapshot, 500);
 }
 
 //视频列表封面图加载