Created attachment 117135 [details]
this picture shows exported image before encoded into video format

SUMMARY
I have not only been having problems with the rendering system itself but I have also been having trouble with audio sync.  When rendering the animation the audio in the finished mp4 file is completely out of sync.  I have noticed when exporting that the frames are numbered starting with the number 30.  This could be something with FFmpeg not encoding frames correctly or it could be with Krita.  Whichever one I am not sure.  

STEPS TO REPRODUCE
1. Create custom doc 1280 x 853 px
2. Set animation frames to 0 to 500 before export
3. Go to Edit -> scale image to new size
4. resize to 1080 x 720 px
5. Go to File -> render animation
6. Make animation export as mp4
7. Make animation export start at 0 frames and end at 130 frames
8. Hit three dots by mpeg-4 video -> select baseline
9. Render animation

OBSERVED RESULT
Audio in export is out of sync with the animation.

EXPECTED RESULT
Exported animation audio is in sync.

SOFTWARE/OS VERSIONS
Windows: 10 Home
MacOS: 
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: 
Qt Version: 

ADDITIONAL INFORMATION

A suggesting to end all of the bugs with export is make your own export built into Krita instead of using an external export involving another program.