Hi GrAnd,
I tried to use vid_get_viewport_fb_d in PLAY mode on SD1000, but I believe that this address is valid only when you turn the camera on, switch from REC to PLAY mode, or after you press MENU button in PLAY mode. If you move to next image on the SD card in PLAY mode, some other memory location is used for a display viewport buffer.
I tried to hook on histogram code to display some true color images on a viewport using hiker_jon's load_viewport code; it works fine the first time, but nothing happens after I move to another image in PLAY mode; if I press MENU, or switch from PLAY to REC and back, it works again. Do you have any ideas what memory locations are used for viewport when we scroll through photos in play mode? Thanks for any suggestions.