The commit b90d0274 introduces uninitialized width and height when we
consider to change the "pixel-aspect-ratio" for some interlaced stream.
We need to check the resolution in the src caps, and if no resolution
info found, there is no need to consider the aspect ratio.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2630>