The quote button will add in the contents of the posting that you are replying to. If the original posting has a video, you can remove this using the BBCode feature.
Firstly, click on the BBCode tab as in the picture below ( number 1) . Then, remove the entire sentence with the video description (number 3 in the picture below).
If you like to write above the original posting, just put your mouse before [quote ..... and press enter (as in number 2). This will then create space above the quote. Next, simply click on the Preview button next to the BB Code button (number 1). You will find the space above the quote and you can simply type as per normal.