Curious to know more about the WD TV Live Hub I downloaded the GPL file of the latest firmware, and had a look at it.
Among a zillion of other files there’s the TARGET.OPTIONS file. I think it contains the compiler options.
In this file, line 212 and on, you can read:
export CONF_PREVIEW_MODE_SUPPORT_VIDEO_FOLDER_ICON_AND_THUMBNAIL=y
export CONF_PREVIEW_WINDOW_RV=y
export CONF_OSD_PREVIEW_WIN_X=902
export CONF_OSD_PREVIEW_WIN_Y=198
export CONF_OSD_PREVIEW_WIN_W=313
export CONF_OSD_PREVIEW_WIN_H=209
I think this is exactly where the preview window sits on the screen.
It seems the position and size of the preview window is hardcoded!
