I have never had success in saving file with same quality after editing. Either it was much bigger, or quality was worse (square blocks etc). I thought MediaInfo program would help, i used to check bitrate of the video, frame rate, codec and make a similar (or close to it) preset in vegas. Never worked. What i have been using as a solution all these years: save video with high quality, then upload to YouTube and then download from there. What are the key characteristics of the source video file i have to check in order to save my editing with the same quality? Maybe there are some good info sources in the internet.