Export Geotiff to ECW without the white areas

Hi Guys,
I have managed to export geotiff as ecw however the ecw exported shows white areas where there is no imagery. For example if my image geotiff is an irregular polygon shape the ecw will show white areas where there is no imagery to fill out a square.
Is this normal and if there is a way I can just export the areas with imagery from geotiff to ecw?
Thanks
I have managed to export geotiff as ecw however the ecw exported shows white areas where there is no imagery. For example if my image geotiff is an irregular polygon shape the ecw will show white areas where there is no imagery to fill out a square.
Is this normal and if there is a way I can just export the areas with imagery from geotiff to ecw?
Thanks
Answers
Also under the 'General' tab, make sure that 'Make background (VOID) pixels transparent' it selected.
This should remove the blank areas from your geotiff.
Make Background (Void) Pixels Transparent