2. Select the video to watch after opening.
3. Click the full screen button in the lower right corner of the video to open the full screen mode.
4. There are three points in the upper right corner of the video. Click it.
5. Just click "go to the opera". After setting up, even if you cut out and open other apps, Youku video will still play in the background and you can hear the sound. After returning to Youku, you can continue watching videos.