For those that are interested, I have spent the last few days playing around with the thumbnail formats and understanding how to read/display etc. as well as how to generate new thumbnails from images and storing them back to the Innotabs.
Thumbnails are stored in uncompressed 16BPP (first bit skipped, 5 bits red, 5 bits green, 5 bits blue) format. The images are stored as a simple array; all the pixels in the first row, then all pixels in the second row and so on...
Most of the thumbnails have a header, but one (Video) does not for some reason! The header format is simply the width and the height, each written as a 4 byte integer value in LSB order. So 8 bytes total.
It turns out that the thumbnail formats for all the different media types are as follows (some of which were already known and posted in the FAQs):
Games: 57 x 57 + header [6506 bytes]
Other: 57 x 57 + header [6506 bytes]
Books: 88 x 88 + header [15496 bytes]
Video: 88 x 88 (no header!) [15488 bytes]
Music: 57 x 57 + header [6506 bytes]
Music is a strange one as the thumbnails as displayed on the 3S version I have are clipped significantly by a ridiculous frame. I tried smaller sized thumbnail variants, and for some reason 56x56 displayed ok, but nothing smaller than that was shown, so it makes sense to stick with the "standard" 57x57 and just accept that it's clipped to hell and back.
Anyway, despite my promise to have something by the weekend, the thumbnail expedition has taken more time than expected. But all going well, and I should therefore be able to bring pretty much everything to the table soon instead of just Videos as I was planning on doing.
Updates soon!
Thumbnails are stored in uncompressed 16BPP (first bit skipped, 5 bits red, 5 bits green, 5 bits blue) format. The images are stored as a simple array; all the pixels in the first row, then all pixels in the second row and so on...
Most of the thumbnails have a header, but one (Video) does not for some reason! The header format is simply the width and the height, each written as a 4 byte integer value in LSB order. So 8 bytes total.
It turns out that the thumbnail formats for all the different media types are as follows (some of which were already known and posted in the FAQs):
Games: 57 x 57 + header [6506 bytes]
Other: 57 x 57 + header [6506 bytes]
Books: 88 x 88 + header [15496 bytes]
Video: 88 x 88 (no header!) [15488 bytes]
Music: 57 x 57 + header [6506 bytes]
Music is a strange one as the thumbnails as displayed on the 3S version I have are clipped significantly by a ridiculous frame. I tried smaller sized thumbnail variants, and for some reason 56x56 displayed ok, but nothing smaller than that was shown, so it makes sense to stick with the "standard" 57x57 and just accept that it's clipped to hell and back.
Anyway, despite my promise to have something by the weekend, the thumbnail expedition has taken more time than expected. But all going well, and I should therefore be able to bring pretty much everything to the table soon instead of just Videos as I was planning on doing.
Updates soon!
