Movie generation breaks when pointing is changed significantly during movie

[Keith Hughitt]

For example,

During some SDO operations (e.g. http://helioviewer.org/?date=2012-04-18T13:22:03.000Z&imageScale=2.4204409&centerX=-26.6248499&centerY=164.5899812&imageLayers=%5BSDO,AIA,AIA,304,1,100%5D) pointing can be significantly shifted such that a movie ROI which previously fell within the range for that datatype is no longer valid.

The result is a 0-value width or height being used with kdu_expand, causing the frame generation and ultimately movie generation to fail.

To get around this, Helioviewer.org should ignore such frames in a larger movie request, up to a point (e.g. <= 10% of movie frames) and simply use the remaining movie frames.