After cropping a video in de DJI App, is it possible to save a file in the sd card, rather than only create an object in the library?

thanks!

The edited video will not be saved in the SD card.
If you run DJI GO on an android device to edit the video, after you making it, then you can get the video here: DJI/DJI.PILOT/VIDEOEDITOR/PRODUCTION
While if you use the IOS device, please connect your mobile device to a PC with iTunes installed, go to application-->DJI GO, you will find "Export Works" file, where the edited videos are available.