[SOLVED] How much post in main page

I was hesitating whether to show the whole Posts on the main page or not. I changed subtemplate postformat.php from the_excerpt to the_content.

But I am not quite satisfied with the result, because my youtube videos are hidden in the main page and I think no one would click the button "read more" to actually view the video. Is there a way to show the video in the_excerpt in the main page ?

Or maybe manually decide whether selected posts are showing the whole content or the excerpt ?

I forgot my page address : www.projektowaniebim.pl