A note about the phrase "LLDV", since you use it recently:
- this is a mode of the display device and not the player, nor the file!
- although the player triggers it based on its setting (e.g. Oppo)
- it has nothing to do with the content itself (can be MEL/FEL DV)
In LLDV mode of a display device it disables its certain image processings (that are enabled otherwise) to reduce latency between itself and the "player" device. This can result in banding/posterization, especially with low bitrate DV content, such as streaming profile 5 MEL DV.
Hence it's not desirable at all to use LLDV mode when watching DV video content.
For example, Sony Oleds don't have full DV support, only LLDV. Even Vincent recently stated the above issues in his late Sony reviews.
Other Oleds that have full DV implementation (LG, Panasonic, Philips) can be set into LLDV mode, e.g. by enabling
player-led DV processing on Oppo.
I should try a couple of my MEL movies with plex on the firestick and see how that goes. That'd be nice.