Blu-ray audio disc style guide

MusicBrainz Style
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With Blu-ray Audio discs becoming more common, I’ve noticed we don’t have a clear style guideline for handling them (or older DVD-Audio discs). These formats typically contain multiple mixes of the exact same tracklist (e.g., a Stereo mix, a 5.1 Surround mix, and sometimes Dolby Atmos) on a single physical disc.

Currently, there are two ways editors are entering these:

Option 1: Single Medium. Repeating the tracks for each mix on one medium (e.g., Tracks 1-10 are Stereo, Tracks 11-20 are Surround).

Option 2: Separate Mediums. Creating a separate medium for each mix (e.g., Medium 1: Stereo [Tracks 1-10], Medium 2: Surround [Tracks 1-10]).

I’d like to propose we officially adopt Option 2.

Grouping everything into a single medium breaks the physical track numbering printed on the release packaging and the disc menus. By splitting the mixes into separate mediums, we can accurately transcribe the track numbers exactly as the listener experiences them. This also aligns perfectly with the existing precedent for SACDs, where stereo and multi-channel layers are split to preserve accurate track numbering.

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(Seen this dicussion before somewhere) I’d stick with Option 1 as there is only one medium. Track numbers can always be fixed in your tagging app.

I assume the reason some people split into separate mediums is due to the way SACDs are done. In those cases there are actual separate layers defined in the physical hardware. SACDS are manufactured and played very different to blurays.

Trouble is with a bluray you’d then have a problem working out what should be in the imaginary separate mediums. Where would you split the files? Where would the extras and videos go?

The audiofile for a track on a bluray is one file with multiple audio streams packed into that one file. It is the hardware that selects which audiostream to playback from that file.

There is a ticket somewhere that is going to eventually allow multiple audiostreams in a single file on MB.

It is also possible to change the track numbering on a medium. Nothing says you can’t keep restarting at 1 again if you are trying to closely follow the artwork.

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Considering how the data is currently handled, I would probably split the different mixes to separate releases (could be pseudo release) as we do not currently have a way to represent those accurately in the database. Having either 1 or 2 becomes problematic when you start tagging as the data is not what is expected.

I’ve been ripping some DVD-Video releases and I’ve seen some different layouts of data on the disc.

For example, a DVD-Video release with one video track, but multiple audio tracks (e.g. stereo and 5.1). DVD can have 8 audio tracks on one video.
These are on the same title and span the same chapters. If I rip it, I would probably take one video and both audio tracks (in same files), or if audio-only, either or both the mixes (all as separate files).
If the release has both of the mixes as separate tracks, tagging on Picard becames problematic: Picard will set the number of tracks to way higher than there are, and the release will show as incomplete. For me both completeness and filetype affect saving of the files.
Adding some bonus tracks to the example above; 3-track concert in stereo and few music videos, in stereo as well.
We get to exercise some custom tracknumbers, lets set the main concert from 1-01 to 1-20 and smaller concert from 2-01 to 2-03, then the music videos from 3 to 6. The main numbers are from the title numbers on the DVD, and tracks by chapter.

I’ve also seen DVDs with the same stereo audio content twice, as there is 4:3 and 16:9 version of all the videos with same audio. These were e.g. titles 1 to 9 in 4:3 and 10 to 18 in 16:9. Certainly, I did not add that as double tracklist on the release (as we do not track video content).

Then you may have some titles with multiple audio tracks and some with only one. How do you the sort them or put the track numbers; 1-stereo-01, 1-5.1-01, 2, 3, 4-stereo-01, 4-5.1-01, etc?

I do not have a Blu Ray drive, so I haven’t spent time on checking how the authoring is done on those. I would expect it to follow somewhat the DVD-Video.

For DVD-Audio, I think I have only one of those, and at that time when I checked it, there were few tools to support extracting info from it, so not much to say.

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I think option 1 is best, at least for now, although it could certainly be worth having some guidelines about track ordering and numbering. (Personally, I try to follow the order in which different mixes are listed on the packaging, but just number tracks sequentially – there may well be better alternatives for the track numbers. Sometimes the stereo mix isn’t mentioned at all, but I instinctively put it first anyway… not sure why.)

Aside from the issue of which medium to put video content in, another problem with Option 2 is that the current interface would misleadingly display 3×Blu-ray under the format for a 1×Blu-ray release with three mixes. With SACD you get something like “Hybrid SACD (CD layer) + Hybrid SACD (SACD layer, 2 channels) + Hybrid SACD (SACD layer, multichannel)”, which is a bit of mess, but at least if you know what you’re looking at it’s a bit easier to see how many SACDs there physically are (1).

Some related things that seem to be normal behaviour, but I don’t think are codified anywhere in style, and maybe could be done differently / better:

  1. Normally these discs are at least technically encoded as video, but if the actual video content is a still image (or something very lightly animated, in the style of a DVD/Blu-ray menu), the recordings are left as audio but different mixes are listed separately (since they need to be linked to different recordings).
  2. If instead the video content is significant – e.g. it’s a concert film – then usually the tracks are listed just once and linked to a single video recording, even if that video contains multiple audio streams with different mixes (usually different channel configurations, sometimes audio commentaries etc.). In this case I try to add an annotation with the list of mixes. (I think there might also be a ticket that would allow linking multiple audio recordings to a single video recording, for these different streams.)
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I’m not sure which Blu-ray audio releases you’re talking about because I do have concert Blu-ray video discs, and things like that but I have not yet come across any Blu-ray audio discs.

I’ve seen some kinds of audio-oriented Blu-ray discs in some shops, but I was not interested and I bought regular CD instead.

DVD-Audio was truly an audio format that you played in audio players.

I don’t think Blu-ray audio discs are anything else than Blu-ray video discs with still images, that you play in your Blu-ray video player, plugged to your TV.
A video format, in fact, right?
I don’t think it’s comparable to DVD-Audio format.
But rather comparable to audio-oriented DVD-Video discs.

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I think the release that sparked this particular forum thread is this one, though there is a very similar one from the same artist here. I have both in hand and previously merged the mediums on the Autobahn release (see main edit here), for the reason raelthelamb mentions above: the release is one Blu-ray disc with three mixes of the album on it, not three Blu-ray discs. Before I merged the mediums on Autobahn I did ask in the #musicbrainz ChatBrainz channel and two editors agreed that merging was the right call. Multilayer SACDs seem to be an exception, not the rule.

Screenshot showing the layout of the Radio-Activity disc, with one title having 12 chapters, a video track, and three audio tracks
Screenshot showing the layout of the Radio-Activity disc, with one title having 12 chapters, a video track, and three audio tracks980×880 102 KB

This is the layout of the actual contents of the Radio-Activity disc, as viewed in MakeMKV. It’s one “title”, with a video track and 3 different audio tracks that can be selected from (Dolby Atmos, 5.1 surround, and stereo). Chapter marks are used to separate each track on the album.

Playing the disc in an actual Blu-ray player, you’re just presented with a simple menu with “Play”, “Track Selection”, and “Audio Options” (where you choose which mix you want to play). The visuals when playing the album are a static image with the current track title displayed. Of possible note is that there are no track numbers displayed anywhere at any point, just the track titles.

I personally think option 1 is the better choice, mainly due to it more accurately representing the actual physical object. It is possible to rip discs laid out like this to match the track layout too, using software like MKVToolNix to split a .mkv file extracted from the disc on the chapter marks, so you end up with a separate .mkv container for each track, then extracting the audio from the container (and possibly converting it to a different format of your choosing, e.g. FLAC).

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I have started collecting these Blu-ray ‘audios’ so have seen quite a few entries in MusicBrainz…

Most of these follow “option 1” above and (imo) this is probably the way to go.

The downsides of option 2 is that it divorces the entry in MB from the physical media release so probably not the way to go.

Ultimately though, it doesn’t really matter - though if moving to different ‘media’ for each mix, there you need to be new media types added - e.g. Blu-ray audio, Stereo; Blu-ray audio Dolby Atmos; Blu-ray audio, multichannel - what’s important is the addition of a style guide to ensure consistency.

To answer @IvanDobsky 's question above, different layers (e.g. for bonus tracks) could reflect mkv files as extracted by MakeMKV, etc. which reflect the authoring - so eg. https://musicbrainz.org/release/7df2bb37-e402-466d-8bf4-e286054d8783 (which I’ve recently converted and iirc) has the main tracks in Dolby Atmos, 5.1 multichannel, and stereo in one mkv so those become media 1-3; quad in a second file; “Rarities” in a third file; and then a fourth file with the bootleg concert. So that would make 6 ‘media’. But then there’s also several video files.

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As far as I am aware, there is no specific Blu-ray audio format, and people are just using this term informally to mean Blu-rays that primarily contain audio content – typically an album with surround sound mixes. (Possibly there will be some bonus content which is honestly video.)

In fact the majority of DVDs that I own in this style are actually encoded as DVD-V, not DVD-A. It seems most people found this a more user-friendly format for playback, so DVD-A became unpopular quite fast.

The other thing to note there is that (unless I am mistaken!) the audio tracks which are indented (DD Suround 5.1 and DTS Surround 5.1) are part of the audio files directly above, and are as a backup if you try to play back the main file through a device which does not support the format. I would propose not listing them separately in MB: DTS should just be lossy encoding of the DTS-HD file anyway. TrueHD is an Atmos format, so it’s not really 7.1 anyway, but object-based, to be played back on essentially any speaker configuration. I think the 7.1 “core” (and the 5.1 in this case) are just the outputs that the Dolby Atmos renderer would give for those channel configurations, and get used if you play the file back on a device that doesn’t support Atmos natively.

(I am an amateur at this, apologies if I made a mistake! Happy to be corrected if so.)

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I guess it’s because there are tons of DVD-Video players around, but very few people have ever had any DVD-Audio players.

There must have been (little bit) more combined CD/SACD players, than DVD-Audio players, probably.

Otherwise, I think that DVD-Video is less user-friendly, as you’d have to switch and leave your TV on, all the time, and use a remote controller to select and start stuff in video menus, instead of just pressing PLAY or NEXT NEXT NEXT buttons of your HI-Fi DVD-Audio player.

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Yep! The lossless formats having a lossy “core” is extremely common on Blu-ray video discs. I agree that they shouldn’t be listed separately, since they’re more a quirk of the format than an intentional part of the release. MakeMKV exposes them since it has the option to rip the lossy core into a separate track from the lossless.

TrueHD isn’t an Atmos format exclusively, but the way Atmos data is usually distributed on Blu-ray discs is as a substream alongside the 7.1 channel TrueHD stream. Devices that can decode the Atmos metadata get the full object-based audio while ones that can’t just fall back to the 7.1 stream. This document from Dolby goes into a little more detail on the encoding, if you’re curious.

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Wow, those incredible crazy formats!
Objects! Wow.

I can’t even appreciate stereo, as I only have one working ear. :face_with_hand_over_mouth:

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It seems like I am outvoted, but I’m going to make one last plea for option 2. It seems crazy to me that you’d just ignore the track numbers on the disc, and use a style which is different to SACD, even though the problem is basically the same - same tracks, different formats. With option one, if you want to play the surround version, you need to start the disc at something bizarre like “track 11”, instead of just selecting the surround media and picking track 1.

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There is, although it is compatible with video players. High Fidelity Pure Audio - Wikipedia

That’s what the Kraftwerk discs discussed above are.

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Huh, interesting: I think it must be quite similar to the standard encoding though if MakeMKV can read it. If I recall correctly, that software can’t read DVD-A, so I have to rip those differently… but I have very few, and it’s been a while, so I could be misremembering, or they could have added the feature in the meantime.

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As stated in the Wikipedia article, it’s mostly a marketing initiative, although (iirc) High Fidelity Pure Audio discs are supposed to be authored in such a way that they can be played and tracks navigated without a monitor. In terms of format they’re just standard Blu-rays and (unlike DVD-Audio vs DVD-Video) can be played (or ripped) any Blu-ray player.

I do think we could do with being able to mark media as either one of the two specific terms - High Fidelity as well as a generic Blu-ray audio.

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Why not a compromise - Option 1, but use “vinyl style” numbering and you can have A1, A2 … A8 for the Dolby Atmos mix; B1, B2 … B8 for 5.1 mix; C1, C2 … C8 for the stereo mix.

Many of these releases do however get more complex by having additional (‘bonus’) tracks which may be stereo only, or may also be available in one or more multi-channel versions, and/or may contain the original stereo mix as well as having a more recently mixed version.

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It is exactly the same encoding, yes. It essentially is just a video blu-ray disc, but it guarantees a minimum audio encoding standard, and the video tracks are usually just a static image.

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The multi-volume approach works just fine with the one-format “bonus” tracks. You just include those tracks only in the appropriate volume.