I have seen various threads discussing the capabilities of the 103 (and 105) but I am not sure if a definitive answer has ever been posted regarding playing media from the USB port(s). As far as I am concerned it will play any audio or video (1080P or below) file from hard drives attached to it IN ITS ORIGINAL QUALITY. Currently I have 7 x 4TB = 28TB directly attached to it (with a USB 2.0 Hub) with all manner of partition sizes, folders and files. It navigates and plays everything without an issue. No other Oppo (except for the 105 and maybe the 203) is as versatile. In fact there is probably no other player or maybe even server that does this as well. Yes, there are no pretty pictures as it is a list structure but who cares. My Sony X800 4K player can only handle a 4TB drive that has a single partition. If you put 2 partitions on there it gets confused. Two or more drives attached also confuses it.
Here goes for the 103:
Blu-Rays - You can place the BDMV and CERTIFICATE folders from the disc you own (after copy protection has been removed) into a AVCHD folder and it will play just like a Blu-Ray with menus etc. So while it won't play ISO's the result is exactly the same as doing that. Alternately you can rip to M2TS or mkv if you don't want the menu structure.
SACD's - Use the 103 to rip SACD's to DSD tracks and put them on the hard drive.
DVD-Audio - Rip to flac files
DVD - Extract VOB files as chapters and put them on the drive. If you don't want the chapters broken up you can make an mkv or MP4 from a DVD.
CD - flac conversion of course
That's it.
Here goes for the 103:
Blu-Rays - You can place the BDMV and CERTIFICATE folders from the disc you own (after copy protection has been removed) into a AVCHD folder and it will play just like a Blu-Ray with menus etc. So while it won't play ISO's the result is exactly the same as doing that. Alternately you can rip to M2TS or mkv if you don't want the menu structure.
SACD's - Use the 103 to rip SACD's to DSD tracks and put them on the hard drive.
DVD-Audio - Rip to flac files
DVD - Extract VOB files as chapters and put them on the drive. If you don't want the chapters broken up you can make an mkv or MP4 from a DVD.
CD - flac conversion of course
That's it.