Its not officially the DVD audio spec keep in mind, its just a DVD with lossless audio which is the same deal but not "official". I mostly use stuff off a flash drive as I can re-write (and the Panny Blu-ray player doesn't like DVD+-RW as a side note), I use DVD+R, but DVD-R is probably the best since SOME formats like AVCHD MUST be finalized on DVD+R but 5.1 192Khz/24bit FLAC will play off a DVD+R...I am well aware of the peak bit rates that FLAC rarely spikes or what standard WAV has as a constant bit rate since it will play both FLAC and WAV but FLAC is much better for bandwidth and space, I think that unless your using high quality DVD's like Verbatim, TDK with at least 16x speed you will get stuttering with high res audio (especially if you include high bit rate video)..I use Sony Accucore(sp?) DVD+R's and they hold up very well...I have been playing The Dark Side of the Moon 5.1 96khz/24bit with ease, this version was a Vinyl Rip that someone did for me and I mixed in 5.1 for fun and discovered that I ended up creating a pretty decent surround mix, I played allot with panning on songs like "On the Run" and manually removed all the pops and crackles...., no delay in loading, pausing or playing. Just pay attention to bandwidth constraints of your media like DVD's for example with audio I would not go over 9.6mbps because then your really pushing it with even 16x Verbatums that will spin faster than they are rated or at least handle higher bandwidth than stated.
I posted a thread about the Panny DMP-BD77 under the blu-ray players section on here, you can find it by looking at my profile and going to "threads" or "all posts" something like that and doing a search of that model and it'll come up. I posted a ton of details about what audio codecs and video codecs do and do not work and I have personally tested a variety of combinations and bit rates because yes I am that much of a tech nerd
Just take a standard DVD-R or DVD+R and throw FLAC onto it either by its self or in an MKV container with a video of equal length that shows maybe the songs or is just blank, I don't care much for adding any video because I usually just turn off the display. I would test both ways out on a flash drive first to see if it works and if it does go ahead and take a look at your user manual, you can find it online if you don't have it. Again disk quality is very important as the player wants to spin the disc much faster than your average DVD-Video from what I'm guessing...some of my older DVD backups with HD video are either unplayable or must be played with the lowest bit rate audio track in order to not stutter like hell.
My Panny was made in March of this year so its relatively new. I was at Target just looking around in electronics while the women looked at clothes (its torture!) and came across several crappy blu-ray players, most of them didn't even decode DTS-MA or TrueHD! Then I came across the panasonic marked down from 89.99 to 75.99 and it was the last unit left in the box! Right on the box in big letters it had the logo's that made any tech nerd/audiophile/whatever grin! Decodes "Dolby TrueHD/Dolby Digital+, DTS-HD Master Audio, FLAC and more!" It had FLAC and MKV container written in big letters too and I just said out loud panasonic must have read my mind!
I also have several of my archived videos on DVD's that I archived in FLAC and/or DTS-MA and I can say that with HD video the Panny BD player handles it well...The DTS-MA can be bit streamed or internally decoded....though bit streaming stutters more often than not with DTS-MA and FLAC is always the best choice, I just like DTS-MA because of the DTS core which means I can play back the video on any computer and any receiver wherever I go to present a video without trouble (I have a MacBook Pro). If you have any specific questions go ahead and post in my thread about the Panny DMP-BD77 or PM me and Ill be happy to respond. If enough people start grabbing Blu-ray players that will play FLAC and want to know how I could write up a more detailed cleaner typed how-to-guide... Sorry about the grammar...I'm a bit scattered brain today on top of rheumatoid arthritis which makes typing a pain to begin with