Problem with Wondershare Uniconverter

[momonone]

Hi all, just wanted to ask, i tried to convert 4k video(.mp4) to full hd video(.mp4), it doesnt convert, then i cancel it, and tried 4k video(.mp4) to hd video(HEVC MP4) it runs perfectly.. may i ask why is this happening?

The reason I wan output my file as MP4 but not HEVC becoz they are smaller...

[Eric-jan]

HEVC is mostly used for 4K because it makes smaller 4K video files at the same rate, so... creating a fullHD video will make a smaller file with HEVC, compared you could even lower the bit rate, and keep the same quality as that of h.264...?
4K resolution files are bigger with h.264 HEVC will make them smaller, you want to convert to FullHD is what you mean ? HEVC + FullHD will make even smaller fiiles encoding them with h.264 will make them bigger. HEVC is more advanced, and that's where the name is standing for

you should use the Create custom option/button and not leave all options on Smart fit, adjust them to the FullHD specs.