I downloaded from DMG file and installed my laptop.
And I tested exporting video project like follow

And I exported MP4 format

But export result is so weired...

Why exporting result like that?.. fix please.
It running on mojave 10.14.1
This was fixed with #447, sorry the website build for Mac hasn't been updated yet.
If it helps, it happens when your export width is not a multiple of 16. If you export at a width of 512 instead of 510, that's a workaround until the website build gets updated.
I'm setting up automated builds for Mac, try out the latest build here: https://github.com/olive-editor/olive/releases
I have the same issue on Ubuntu 18.04 LTS and here is an image of the exported video.

THANKS FOR OLIVE!
As I said, this was fixed quite some time ago. Which version of Olive are you using?
My version is Olive (January 2019 | Alpha | c8aec60)
That's _extremely_ old. Please update to the latest build and this issue should disappear.
Thanks for your reply!
Most helpful comment
That's _extremely_ old. Please update to the latest build and this issue should disappear.