credits

I was uploading another YouTubers Gmv and Amv and translate them to another language and I give the credits to them in my description but I was wondering if this is legal or I should tell the owners that I take their video and use it and if I don't tell them can youtube delete or ban my...

Hi guys! I'm just new here in YTtalk, I have a question regarding Copyrights, what if someone uploads a short clip of their gaming video and I download it without telling them. The downloaded video is added to my video hightlights. But in my video description, I add their names as a Credits to...