The black screen occurs due to hardware acceleration setting on your PC.
Here are a few things you can try:
1. Windows Media Player has a feature to disable video acceleration. If you are recording only video from the player then you can turn off video acceleration here. Try looking for a similar setting on Realplayer.
2. My Screen Recorder can automatically disable your computer's hardware acceleration just before it starts recording. You can use this option to record from Realplayer.
3. Finally, you can turn off your system's hardware acceleration from the Window's Control Panel.
To know more about turning off hardware acceleration, please refer My Screen Recorder's help file. To read the help file online, visit:
https://www.deskshare.com/help/msr/Index.aspxAlso, make sure that you are using the latest version of My Screen Recorder. To download the latest version, visit:
https://www.deskshare.com/msr.aspx