basetransform: allow using different padded caps for allocation query
@ndufresne
Submitted by Nicolas Dufresne Link to original bug (#791764)
Description
Right now it's fixed in the GstBasetransform, the caps used to run the allocation query and get a pool cannot be different then the caps negotiated on the src pad. With latest analyses of the crop meta, an element may request largest buffer using this method and apply a crop meta on it. This is of course only for cases where GstVideoAlignment is not option (crop that is possibly not aligned to the sub-sampling, video-alignment is not not implemented (even though you cannot know in advance this one).