Scroll image file vertically

[Who]

If it is possible and not terribly difficult, I'd like to see a filter that operates similar to the logo filter in that it can copy over or replace a section of video with a static image (.bmp, .jpg, or .png), however instead of displaying the full image all at once I would like it to move from the top to the bottom within the given duration.  So in other words, let's say you have a video that is 1920x1080 and you have an image that is 1920x3240 (or anything larger than 1080) and in the filter you indicate that you want to scroll from top to bottom in 10 seconds.  When the filter begins it would use the top 1920 by 1080 pixels of the image file and overlay the existing video frame, applying any transparency given.  On the next frame it would move down the image file slightly and use that part, and so on until the last frame to be replaced (at the 10 seconds mark) would be from the bottom 1920x1080 of the image file.

In the second example let's say that instead of a 1920x3240 image you have a 960x3240 image (half the width of a 1920x1080 screen) and you specify an x offset of 960 in the filter.  In that case the image would scroll on the right hand side of the screen while leaving the existing video image on the left.  Again, ideally it would work just like the logo filter but with the option to scroll downward (or upward?) in an image file that's larger than the current vertical screen size for a given duration.  The obvious use for this would be adding or fixing errors (such as spelling mistakes) in scrolling credits, since you could export them as a series of static images, fix them and stitch them together vertically in an image editing program, and then use this filter to bring them back in with the original scroll rate.  I have no idea how difficult this would be, so it's just a suggestion.

(Some people might also have a desire to scroll horizontally - I can't think of any reason to do that, though).