The current code is memsetting the GstVideoFrame.data address to 0s (which
causes a segfault). This member is actually an array of data buffers (one for
each plane). This fix iterates over each data plane to clear them all.
https://bugzilla.gnome.org/show_bug.cgi?id=695655
Add support for GstVideoMeta and GstVideoFrame. Remove some redundant fields
that are also in GstVideoInfo. Don't disable the shader code, it does not
look broken.