I'm trying to create image pyramid of multiple smaller images for GeoServer use. I have done this by first creating virtual dataset with
gdalbuildvrt and then with
The problem I'm having is, that the original images are disjoint, and thus the virtual dataset has a lot of empty space with no data (rendered as black). I would want to render this area transparent.
The images are all JPEgs with YCbCr colorspace thus they do not contain alpha channel, nor does the original data have nodata value set. Also the images contain all pixel values in 0-255 range (i.e. I cannot use
gdal_translate without getting holes in the picture). I have narrowed it down to two solutions: One would be to use external mask, but I'm wondering the performance impact of this solution. Not to mention the need to store an extra image that is almost completely empty. The second solution would be to edit every single pixel in the original images so that none would have value 0. then use 0 as nodata value.
Any ideas which method I should use? Or neither?