i think i found something which can be the problem with the "minidlna" server in dir-657
Set your media share directories. As the config file states, these are separated by multiple media_dir lines, and content is defined by a preceding A, V, or P. Keep in mind that Linux is a case-sensitive OS, so your directories MUST match your file structure exactly, or the files will not be found. My finished share section looks like:
media_dir=V,/mnt/share/Videos
media_dir=P,/mnt/share/Pictures
media_dir=A,/mnt/share/Music
**Important** a bug exists in the scanner used in minidlna. Enter any music libraries last, because they can cause the movies scanner to freeze.
Yesterday magicaly the name of the server appears on my dlna players, i start to listen music -> ok
restart the router -> no more dlna server
i called D-link France on Tueday, the guy on phone wasn't able to tell me if the DIR 657 was DLNA compatible, he call me back in the afternoon to tell me, if you want to have a media server you should buy a NAS, router DIR 657 is not design to share media, it's a router.
the guy was incredibly stupid.
So i hope a firmware update as soon as possible, and i will be please to test it !