Would downloading and streaming while Wi-Fi is on still take up cellular data?

I turned cellular data off on my iPhone and turned on Wi-Fi. I'm allowed 7GB of data each month and the cell carrier told me not to make and big downloads or stream videos or it will slow my internet down. If I do these things while Wi-Fi is on, would I still be using up the 7GB? Or can I download and stream freely like I did with my iPod?

As long as you have a Wi-Fi connection, you are not using the 7GB allotment from your carrier.