The YouTube app that comes pre-installed on the Galaxy S4 doesn't allow you to read videos in background.
However, sometimes we may want to listen to the audio of our favorite Youtube videos, while performing other tasks. To overcome this drawback:
- Download and install YouTube ON from Google Play.
- Launch Youtube ON and search for the video of your choice.
- Simply press the Home button and the video will be played in the background.
- Open the application of your choice.