Two Sound Mixing (Primary+Secondary into one track)
If you use Secondary Sound Device and check the "Two Sound Mixing" option, a video with one audio track will be created.
If you're not a video specialist, please check this "Two Sound Mixing" option.
How to record computer and microphone sound separately
If you are a video specialist, you may need to edit the sound of the computer and the microphone separately.
In such a case, if you uncheck the "Two Sound Mixing" option, a video with two audio tracks will be created.
Since Windows Media Player and YouTube do not support videos with two audio tracks, you will only hear one audio track of the computer or the microphone sound.
If you use VLC Media Player, you must select a specific audio track to hear the computer or microphone sounds.
How to change 2 audio tracks to 1 audio track
If you use Bandicut, you can save a specific audio track while maintaining the quality of the original video.
After opening a video file from Bandicut, select [1] or [2] as shown below, and choose the "Save only selected video and audio track" option to create a video with the audio you have selected.