Images for every youtube videos are hosted their server. You can image of any frame and can display on your site. I want to do same with other video sites without using getting ffmmpeg installed. Because my share hosting service will not le me do this.
Please suggest me on the same. I want to do it in PHP
It won't work, at least given two conditions:
Point 1 is rather improbable, at least I don't know of any video site that does this. Point 2 is really really a lot of work, I'd say it's impossible without deep and profund knowledge of the video codec.
So I guess, your best starting point is to either drop this feature or use a hoster that offers you ffmpeg.