Authoring errors in studio-released Blu-rays

[A.Fenderson]

In the process of backing up my Blu-ray collection using BD-Rebuilder, I've noticed some pretty strange authoring mistakes before (10+ duplicate identical audio tracks, etc), but here's one that really threw me off: one of the .m2ts files on my Baraka Blu-ray (00008) appears to be the main-menu background loop video for Rambo 3!

Please share some of the strangest or stupidest Blu-ray authoring errors you've seen.

[dvdboy]

Identical Audio tracks might not be an authoring error. Due to the nature of menu authoring on Blu-ray you have to ensure that the menus have the same number of audio tracks as the feature, as the audio stream switching happens immediately.

Some things seem a backward step to DVD...

[A.Fenderson]

I'm pretty sure I've seen menu m2ts files with lower number of audio tracks than other files on the same disc, but I think I know where you're coming from (see below).

My theory about what's happening specifically with the duplicate audio tracks is this: to be in-spec, a disc has to have an identical set of audio track types/specifications across every segment in a playlist, and this makes perfect sense. While it would be easy enough to have the authoring software check simply for compliance with this logic, some authoring software out there was written very poorly, and instead it just enforces that all segments referenced within a particular menu structure (or something similar) have identical sets of audio track types/specifications regardless. Furthermore, apparently, it stupidly enforces that every segment contain (at minimum) the same number of audio tracks as the main feature playlist (or some other aritrary m2ts file) contains. And here's why I've come to that conclusion:

The Notebook: 10 duplicate 192kbps DD audio streams per m2ts file on some of the extras (those with 2 unique audio tracks). That's 2 Megabits per second wasted on duplicate audio tracks. Other m2ts files with only one unique audio track per file have I believe 5 duplicate tracks each--this mirrors the 5 (unique) audio tracks that the feature playlist/m2ts file(s) contain.

My backup theory on this: an ill-fated attempt by the studio to make backing up the disc that much more difficult/space-consuming.

My theory on Baraka having the Rambo 3 main menu loop: someone is freaking retarded.

[digitalvideo]

I,

We have to duplicate track for use of resume or topmenu/topmenu because in this two case the player not memorize the track you come from (except for subtitle).

[Ghitulescu]

I think I remember some DVD9 in the good old days, those the main movie + the original sound was/were less than 3GB, additional languages and variants (DD1.0, DD2.0, DD5.1) and plethora of bonuses were added - a collectible item should be DVD9, who's gonna trust a DVD5 one ;)

[A.Fenderson]

Identical Audio tracks might not be an authoring error. Due to the nature of menu authoring on Blu-ray you have to ensure that the menus have the same number of audio tracks as the feature, as the audio stream switching happens immediately.

Some things seem a backward step to DVD...

I,

We have to duplicate track for use of resume or topmenu/topmenu because in this two case the player not memorize the track you come from (except for subtitle).

Not buying it: the second Blu-ray I checked (Brooklyn's Finest) had exactly one audio track for each of the two menu m2ts files, and 3 audio tracks on the feature m2ts file. Again, this is a product of lazy authoring and/or lazy authoring-software developers.

[Eric69]

Studios titles often used multiple audio tracks for the reason DVDBoy described

[Oleg Rode]

Please share some of the strangest or stupidest Blu-ray authoring errors you've seen.
Hatsune Miku | 39's Giving Day Project DIVA - all extras on BD have major visual glitches (the snow noise on the screen, video is impossilble to watch)
Animusic HD - on sixth track LFE & one of the rear channels are mixed.
Dark World - 3D Blu-Ray has at least 3-5 minutes of 3D content. Well it is not a glitch, but what is the reason to wear 3D glasses to watch it? :)

[A.Fenderson]

Studios titles often used multiple audio tracks for the reason DVDBoy described

Is it actually mandatory in the BDMV specs, as DVDBoy and digitalvideo seem to be saying? Because commercial BDs exist that don't do this, and they don't seem to break playback. My guess is that the person authoring the disc (or writing the authoring software) couldn't come up with a more elegant solution, as described below, and lazily just implemented the BD structure in such a way that it works but is wasteful of space.

Beyond that, the menu files are generally few and small, so my real issue, though not stated explicitly in the OP, was with extras/bonus content that have multiple duplicate (bit-identical) audio tracks which are actually physically written to the disc--it seems that, if possible, a far more elegant solution would be something akin to what jdobbs mentions here (http://forum.doom9.org/showpost.php?p=1502204&postcount=743)that BD-Rebuilder does to save space: leave out the deselected (or, in this case, unnecessary identical duplicate) audio tracks and change the BD structure so that these additional audio tracks as accessible via menus/mandated as per specs/etc merely point to one of the remaining, physically-present audio streams' PIDs. I just don't see how it could possibly be mandatory in the BD specs that in certain cases bit-identical duplicate streams have to be physically written to the disc--it's just too stupid a concept to accept.

[mp3dom]

For what I've seen, you can set a Title Playback to be an 'Interactive title' (default is 'Movie Title'). In this way, you can have multiple Playlists on the same Movie Object (which in general is not allowed) and - unconfirmed - seems that it acts more like the old 'dvd menus' where you can retains audio/subs selection without having the same amount of audio/subs as the feature movie. I don't know deeply what's the difference between Interactive and Movie Title option as I haven't seen docs explaining the differences.