Also try the app YT Mobile for playing YouTube in the background
Sometimes you are watching a video on your Android device, and you want to have the option to play video in background, so you can do other tasks. Samsung added the Multi Window features to watch a movie in half of the screen and do other tasks on the other half. But how about minimizing the playing video screen and do other stuff with Android while listening to the sound of the video?
Do as follows to play video in background on any Android device:
2. Browse and play the video you want to be played in the background
3. Press Menu button (or the 3 dot icon), and then select Play
4. Make sure "Background Play" is checked
5. Now, you can press Home Button and as you see, the video is playing in the background
** There is also a shortcut for enabling Background Play, which is tapping and holding the Play button, instead of just tapping it to play a video