I tried to add a 3D object to a clip by following a youtube video. But clip doesn't show up in the render or in the compositing tab. It show up even in the camera view. I didn't change any settings. please help. Thank you.
And the rendered images has only the cube in it like in the picture above.
What you are missing is the alpha channel on the render layers. Without an alpha channel the "alpha over" will fail. Enable Film>Transparent so that the areas with no geometry will be "transparent".
I encountered the same challenge. However, marking it Transparent under Film under Render Properties made the motion tracked video clip show in render view.
That is, Render Properties > Film > Transparent turned ON.
I know this isn't a real answer but I also struggled really hard following cg geeks tutorial. i would feel sorry for people who try to do it. It just goes way too fast and he doesn't explain anything properly.It was very frustrating. However, I see you didn't set up the nodes properly. I did this same tutorial a few days ago and the result was quite successful. Maybe you can copy the nodes and change the images. Hope this saves a lot of time for you. Good Luck!
Or press N and open the side menu in tracking panel...and go to track menu under footage and change focal length from 0 to any number..may be you have accidentally changed focal length to 0 ..if yes then it will solve your problem.
