To supply more information I have recorded the same game for exactly 5 seconds with the same codec (MagicYUV) and autiosettings with either Bandicam and Dxtory.
I then inspected the encoding Details with MediaInfo. Here is the screenshot of the comparison:
Bandicam is left, Dxtory right.
The only noticeable difference is the writing application obviously. But also the Dxtory recording maintains the original source form (MagicYUV) somehow.
But most importantly you can see that the audio streams are identically! Why the heck does it take soooo much longer to extract audio from Bandicam recordings than from Dxtory? 6-8 minutes in comparison to just 20-25 seconds!
It must have something to do with how the Bandicam Encoder wraps up the final file. It seems to be severely lacking in performance optimization...