Resolution of Video is decreased after Render

[Mr. CS]

After I render the video the resolution of the video is decreased, see this video's resolution(when full screen landscape) : https://youtu.be/vRk-wG-HnQw   

I don't know if this bug is only on android. Whatever resolution I use, after I render the resolution is decreased.

This is not a problem with YouTube

because After I rec the video, the size is good It's happened after I rendered.

Plz Help!

[Mr. CS · Accepted solution]

I got the answer from Adobe Care.

[Shane21800936tjad]

I have just bought a year's subscription. I hope this isn't a mistake. The rendering of my 4k 60fps iphone video has been downgraded to a blurry rubbish clip. If this is what rush can do then I would prefer to cancel.