Blu-ray movies are playable on Linux right now, but there is no broad support, some movies will lack audio support, and a lot of manual intervention is required. If there is Digital Rights Management on the Blu-ray disc, the end-user must install a utility to dump and decrypt the high-definition files, manually input the DRM AACS key, and take other steps to watch a legally purchased movie. When it comes to FFmpeg support, Blu-ray discs using DTS-HD MA for their audio format do not work. A few months back there was some code proposed to the FFmpeg project that would partially address this problem, but FFmpeg developers rejected the code. Neither Diego, Baptiste, nor Robert have a Blu-ray drive, so at this point they have no personal interest in Blu-ray support. Diego reiterated they are interested in supporting "every format under the Sun and thus certainly Blu-ray," but their bar to accept patches is quite high and they will only reject patches if there are technical issues. All three of the developers though agree that Blu-ray support will appear in FFmpeg, but are unsure of when there will be proper support.
Well, Blu-ray support may now come to Linux sooner rather than later. Following that Phoronix interview, a few interested parties have offered up Blu-ray drives and media to the FFmpeg developers. Robert Swain has shared with Phoronix this morning that they are now deciding on a suitable FFmpeg developer to receive these donations to begin work on Blu-ray support.
Robert also shared that discussions are leading to possibly having the AACS decryption implemented in FFmpeg. With Blu-ray, the AACS decryption is done as part of the de-muxing process, which means it would need to be pushed into FFmpeg. The Advanced Access Content System keys though for Blu-ray support would be stored elsewhere (say in ~/.aacs).
This is a good sign that Blu-ray support on Linux through FFmpeg is hopefully moving forward.