Editing Title, adding description and tags : SEO impact

I have uploaded few Videos.

After uploading videos, If I change description, title and tags. Am I going to loose current rankings?

If those keywords are still covered in the new article then chances are there to stick with your current serps or else you'll see the movements.

In description or in title. I have added few more words to title. Added lot of text in the description.

On old videos that have very strong rankings, I've edited, removed, and even added descriptions and tags to videos that had none, and they remained in the exact same positions in search results. On new videos, I've edited titles, descriptions, and tags and the rankings have changed, however videos typically bounce around for the first few days anyways so its not possible to link the ranking changes to the info I changed for those videos.

It would make sense for YouTube to change a video's rank if a drastic change is made to its on page seo, however I don't have any data or anecdotal experience to back up that thought.