Discsubtitle handling

[simbun]

Hi Simon,

I'm looking at another solution for remote/offline/android auto usage but the way MinimServer handles embedded artwork is causing issues. The other solution is able to use external artwork for album (folder.jpg/cover.jpg) but discsubtitle must be embedded (as DISC), the problem being whenever MinimServer encounters any embedded artwork it uses it for album/track.

The only way around this would be to duplicate folder.jpg to <album>.jpg for MinimServer, but it feels a bit clumsy. Obviously I could ask that you use embedded DISC images for discsubtitles but that's a much bigger change, so instead, would it be possible to limit embedded images to just FRONT (as that's all they're used for)?

On a related note, would it be possible to return discsubtitle matches from the album search (so I can find 'Please Please Me' from the 'The Beatles in Mono' boxset)? I assume the search would have to return the full album but anything more specific would be great e.g. the discsubtitle as an album, or only the tracks belonging to the discsubtitle under the album.

Thanks for your consideration.

[simoncn]

What is the other solution that you mentioned in your post?

The UPnP specification defines how the server sends artwork to the control point and the various tagging formats define how artwork can be embedded in an audio file. There is no standard specification for how artwork is associated with albums, discs, tracks and index entries for Genre, Artist, etc., so each media server has its own rules for this.

The rules used by MinimServer have been refined over many years with feedback from users to arrive at the current set of rules which seem to be working well. I am reluctant to make any change to these rules that would produce different results with the tagging and embedding schemes of current users. Maintaining upward compatibilty for users when new versions and updates are released has always been an important principle for MinimServer development.

What exactly do you mean by FRONT and DISC? Is FRONT the ID3v2 APIC picture type (front cover = 3, etc.) or is it the value of the APIC description string? There is no APIC picture type for DISC, so I presume this would be a description string. Please clarify. Also, how would FRONT and DISC be encoded in the COVR atom in an Apple MP4/M4A file?

Regarding your suggestion for search results, the semantics of UPnP Search are clearly laid down in the UPnP specification and MinimServer implements this specification as closely as possible. UPnP doesn't have a concept of Disc (an unfortunate omission), so there is no standard mechanism for a UPnP server to return a DiscSubtitle value and the MinimServer implementation has no easy way to add this capability. Also, I don't quite understand your scenario with The Beatles in Mono and Please Please Me. What UPnP Search query would you like to return a different result in this case?

Some time ago the concept of album groups was discussed (see this post). This might be a better way to handle The Beatles in Mono (tagged as an album group) and Please Please Me (tagged as an album). Would adding this feature provide a solution for your request?

[simbun]

(09-06-2025 21:26)simoncn Wrote:  What is the other solution that you mentioned in your post?

It's an OpenSubsonic solution using Symfonium as the control point.

(09-06-2025 21:26)simoncn Wrote:  The rules used by MinimServer have been refined over many years with feedback from users to arrive at the current set of rules which seem to be working well. I am reluctant to make any change to these rules that would produce different results with the tagging and embedding schemes of current users.

I was only suggesting that the artwork rules would/should only consider FRONT images (as that's how they're being used in MinimServer), but I appreciate that some users/software may have assigned them incorrectly.
This assumes of course that the library you use offers this level of detail.

(09-06-2025 21:26)simoncn Wrote:  What exactly do you mean by FRONT and DISC? Is FRONT the ID3v2 APIC picture type (front cover = 3, etc.) or is it the value of the APIC description string? There is no APIC picture type for DISC, so I presume this would be a description string.

The Vorbis documentation calls it 'Media label' (type = 6) and ffprobe reports:

Code:

Stream #0:2: Video: mjpeg (Progressive), yuvj444p(pc, bt470bg/unknown/unknown), 200x200 [SAR 150:150 DAR 1:1], 90k tbr, 90k tbn, 90k tbc (attached pic)
    Metadata:
      comment         : Media (e.g. label side of CD)

(09-06-2025 21:26)simoncn Wrote:  Please clarify. Also, how would FRONT and DISC be encoded in the COVR atom in an Apple MP4/M4A file?

I have no knowledge of anything apple but I converted a flac with embedded FRONT and MEDIA to mp3 and m4a and whilst foobar and Mp3tag recognise both images ffprobe only reports a single image/stream from the m4a:

Code:

Stream #0:1: Video: mjpeg (Progressive), yuvj444p(pc, bt470bg/unknown/unknown), 200x200 [SAR 150:150 DAR 1:1], 90k tbr, 90k tbn, 90k tbc (attached pic)

  samples.zip (Size: 14.45 KB / Downloads: 1)

(09-06-2025 21:26)simoncn Wrote:  What UPnP Search query would you like to return a different result in this case?

I was asking that an album search of 'Please Please Me' would also return any albums that contained a matching DiscSubtitle.

Currently when I search for 'Sgt. Pepper's Lonely Hearts Club Band' only the original release is returned, the proposed functionality would return the albums:
Sgt. Pepper's Lonely Hearts Club Band
The Beatles In Mono
The Beatles

Obviously it would be nice if when clicking 'The Beatles in Mono' only the 'Sgt. Pepper's Lonely Hearts Club Band' DiscSubtitle(s) were returned, but I never thought that would be possible.

(09-06-2025 21:26)simoncn Wrote:  Some time ago the concept of album groups was discussed (see this post). This might be a better way to handle The Beatles in Mono (tagged as an album group) and Please Please Me (tagged as an album). Would adding this feature provide a solution for your request?

That is what I've been waiting for but it's still not perfect:

• boxsets contain discs that were never albums and that I wouldn't really want to see outside of the box e.g. extras
• it's not a standard
  

I would find that solution perfect for grouping series e.g. Now That's What I Call Music.

[simoncn]

Thanks for these clarifications and for the sample files. I will try some tests and post back here.

[simoncn]

Thanks for clarifying that FRONT is the picture type 3 'Cover (front)' and DISC is the picture type 6 'Media'.

When MinimServer reads picture information from a FLAC or MP3 file, it looks for a picture as follows:
1) Use the first picture with type 'Cover (front)' if any such pictures are found
2) If no 'Cover (front)' pictures are found, use the first picture of any type

This means that when MinimServer scans a file tagged with both 'Cover (front)' and 'Media' images (in either order), it will use the 'Cover (front)' image and ignore the 'Media' image. I have confirmed that MinimServer is doing this with your test files. Does this work for your use case?

I also checked what happens with the M4A file. This has an unusual format with two blocks of tags. The first tag block is read by MinimServer and contains a single image of type 'Cover (front)'. The second tag block is not recognised by MinimServer and contains two images of type 'Cover (front)' and 'Media'. I will need to do further investigation into what this second tag block is and whether MinimServer should be reading it.

[simbun]

(14-06-2025 07:15)simoncn Wrote:  This means that when MinimServer scans a file tagged with both 'Cover (front)' and 'Media' images (in either order), it will use the 'Cover (front)' image and ignore the 'Media' image. I have confirmed that MinimServer is doing this with your test files. Does this work for your use case?

The problem with that approach is that embedded FRONT overrides <discsubtitle.jpg> and embedded DISC (media), so when I add tracks to a queue it's the FRONT image not the <discsubtitle.jpg>/embeded DISC image that's presented.
As mentioned in my initial post, currently the best solution is to copy folder.jpg (because folder.jpg is used for a lot of other purposes) and rename it <album.jpg>.

Ignoring M4A for a second, if you already have logic that handles FRONT and OTHER (non-FRONT embedded) wouldn't it be possible to only use OTHER if nothing else exists (obviously it would be nice if we could use DISC for discsubtitle artwork but that's a bigger change)?

Whilst the existing artwork behaviour isn't ideal it's not something I'm going to lose sleep over, being able to search for discsubtitles would be the big win.

Thanks for taking the time to investigate.

[simoncn]

(14-06-2025 10:50)simbun Wrote:  Ignoring M4A for a second, if you already have logic that handles FRONT and OTHER (non-FRONT embedded) wouldn't it be possible to only use OTHER if nothing else exists (obviously it would be nice if we could use DISC for discsubtitle artwork but that's a bigger change)?

This should be how MinimServer works currently, as described in point 2) of my post #5. Your test files didn't include a file that has an embedded DISC image and no other embedded images, so I haven't verified this by testing.

Quote:Whilst the existing artwork behaviour isn't ideal it's not something I'm going to lose sleep over, being able to search for discsubtitles would be the big win.

I will look at this when I can (the code for search is quite complex) and post back here.

[simbun]

(14-06-2025 13:01)simoncn Wrote:  

(14-06-2025 10:50)simbun Wrote:  wouldn't it be possible to only use OTHER if nothing else exists (obviously it would be nice if we could use DISC for discsubtitle artwork but that's a bigger change)?

This should be how MinimServer works currently, as described in point 2) of my post #5. Your test files didn't include a file that has an embedded DISC image and no other embedded images, so I haven't verified this by testing.

When I said 'nothing else exists' I meant external too. Whilst it doesn't take OTHER over %album%.jpg it does over folder.jpg.

  FolderFrontDisc.zip (Size: 34.91 KB / Downloads: 0)
Rename 'FolderFrontDisc1.jpg' to 'FolderFrontDisc.jpg' to test %album%.jpg which does work.

(14-06-2025 13:01)simoncn Wrote:  

(14-06-2025 10:50)simbun Wrote:  Whilst the existing artwork behaviour isn't ideal it's not something I'm going to lose sleep over, being able to search for discsubtitles would be the big win.

I will look at this when I can (the code for search is quite complex) and post back here.

Damn, and there I was thinking it would just be a change to a where clause ;-)

[simoncn]

Support for DISCSUBTITLE search is now available in MinimServer update 260.

[simbun]

(10-09-2025 15:51)simoncn Wrote:  Support for DISCSUBTITLE search is now available in MinimServer update 260.

Thanks for the discsubtitle search, and the MinimWatch fix.

Another great release!