Video Quality Loss after Rendering in VSE

I rendered an animation in a 720p-png format and the images looked HQ. After re-rendering them into video in VSE the video lost its quality and looked blurred. (I tried higher bitrates and different formats but nothing worked). How to keep my video quality as good as images?

So what settings were you using to render the final video ?
What other applications have you tried and what were those results like

Also the VSE stretches any source images to fit the current scene dimensions. These may not be the same as the original rendered dimensions. Make sure that they match before you test bitrates and codecs.