Using the correct recording screen resolution for Youtube will produce video that does not appear stretched and does not have any black bars at the top or bottom.
There are two ways to set the correct resolution. My Screen Recorder allows you to change the screen resolution before beginning recording or to record just a specific region of the screen. You can change the resolution before recording from the Settings.
To record just a portion of the screen, use custom region screen recording.
These are the display dimensions for Youtube:
720p: 1280x720
480p: 854x480
360p: 640x360
240p: 426x240
