If "kkkkkkkkkkkkkkkkkkmp4" is an actual file on your computer that won't open, it may be a corrupt MP4. You might need to check your system's or video drivers if you are seeing a black screen or experiencing playback issues.
The string "kkkk..." is a common way to represent laughter in several languages (especially Portuguese). kkkkkkkkkkkkkkkkkkmp4
The search results suggest several possibilities for what you might be looking for: If "kkkkkkkkkkkkkkkkkkmp4" is an actual file on your