High-Resolution Story Video and Audio file - Mortal Kombat (2011)

The video files in the Steam version of the game are heavily compressed, which heavily degrades the visual quality as well as introduces audio artifacts. In this archive are all the cutscenes ripped from the PS3 version which are considerably higher quality. All languages are allegedly supported.

Credit goes to whoever was it on guru3d that originally discovered the cause. The thread has since been archived unfortunately.

From installation.txt

Replace the *.bik files on the game's folder.
“..\Steam\steamapps\common\MortalKombat_KompleteEdition\DiscContentPC\Movies”

Default Steam path on Windows:
(32-bit) C:\Program Files\Steam
(64-bit) C:\Program Files (x86)\Steam

Note: A backup for the original files is recommended.