According to Assets Sizing Guide and Managing Assets with the Touch-Optimized UI
The file size limit seems to be 2 GB. The latter page also explains how to set the sizeLimit attribute (was able to upload upto 10GB from browser by increasing the sizeLimit) (/libs/dam/gui/content/assets/jcr:content/actions/secondary/create/items/fileupload),
the 2GB limit is imposed by the browser. Additionally In order to add a larger file, it can be done through AEM Desktop also
Kautuk Sahni