Multiple entries in playlist

[DavidHB]

I'm posting this as a general query, because I don't know whether or not it relates to expected behaviour, or whether the behaviour is a function of MinimServer or the control point (Bubble DS in my case).

The specific case is as follows. In my collection, I have two recordings of the Mendelssohn Third Symphony. If I browse through Genre, Composer, Composition to right-click on the entry for the symphony, and then select Play, I get a playlist in which each symphony appears multiple times. Ideally, of course, I want a playlist that references each recording only once.

Thanks to the useful feature in Bubble DS whereby the number of entries within a particular item is shown once that item has been accessed and the entries counted, it is easy to see what is going on. Below the entry for the symphony within Composition that are entries shown as 2 Albums, 2 items (the works are grouped), Artist, AlbumArtist, Date, All Artists, Conductor and Orchestra. If the playlist is created at the Composition level, playlist entries will be created for all these items, duplicating the entries (in this case) a total of sixteen times.

The problem can of course be avoided by refining the selection within the composition entry, but it would be nice not to have to drill down to the nth degree when all that is wanted is to play the available recording(s) of a particular work. Is it possible for MinimServer to refine the playlist selection sent to Bubble DS so that it does not contain duplicates? Or is this something I should expect the control point to do? If the entries are drawn from a list cached by the control point, there is clearly nothing that MinimServer can do to help.

Thanks in advance for any advice.

David

[simoncn]

(24-03-2014 19:08)DavidHB Wrote:  I'm posting this as a general query, because I don't know whether or not it relates to expected behaviour, or whether the behaviour is a function of MinimServer or the control point (Bubble DS in my case).

The specific case is as follows. In my collection, I have two recordings of the Mendelssohn Third Symphony. If I browse through Genre, Composer, Composition to right-click on the entry for the symphony, and then select Play, I get a playlist in which each symphony appears multiple times. Ideally, of course, I want a playlist that references each recording only once.

Thanks to the useful feature in Bubble DS whereby the number of entries within a particular item is shown once that item has been accessed and the entries counted, it is easy to see what is going on. Below the entry for the symphony within Composition that are entries shown as 2 Albums, 2 items (the works are grouped), Artist, AlbumArtist, Date, All Artists, Conductor and Orchestra. If the playlist is created at the Composition level, playlist entries will be created for all these items, duplicating the entries (in this case) a total of sixteen times.

The problem can of course be avoided by refining the selection within the composition entry, but it would be nice not to have to drill down to the nth degree when all that its wanted is to play the available recording(s) of a particular work. Is it possible for MinimServer to refine the playlist selection sent to Bubble DS so that it does not contain duplicates? Or is this something I should expect the control point to do? If the entries are drawn from a list cached by the control point, there is clearly nothing that MinimServer can do to help.

Thanks in advance for any advice.

David

I have tried this and it seems that BubbleDS is doing an aggregated recursive UPnP Browse operation of the selection's complete subtree by sending a series of Browse requests and combining the results, without eliminating results that have duplicate resource information.

There is nothing that MinimServer can do to eliminate these duplicates, because there are no duplicates in the results that MinimServer sends for any individual Browse request. The duplicates arise because of the aggregated series of Browse requests issued by the control point.

There are two possible solutions:

1) The control point could do an aggregated recursive series of UPnP Browse requests and remove items with duplicate resource information from the aggregated list.

2) The control point could issue a single UPnP Search request instead of an aggregated recursive series of UPnP Browse requests. This would give MinimServer the opportunity to identify and eliminate duplicates in the result set. (I'm currently working on a change to MinimServer to ensure duplicates are removed from Search results.)

[DavidHB]

Thank you, Simon.

I did what I should have done before posting, and tried the same browse sequence in Kinsky. The results were the same as those in Bubble DS. So it seems that more than one control point is behaving in the way you suggest, and we'll have to live with what is only a fairly minor irritant unless or until that behaviour is changed.

It would be interesting to know Bubbleguuum's view if he ever reads this; there may of course be a good reason for making the recursive series of search requests. Alternatively, perhaps this was just not an issue until you came up with the concept of intelligent browsing.

David

[simoncn]

(24-03-2014 23:41)DavidHB Wrote:  Thank you, Simon.

I did what I should have done before posting, and tried the same browse sequence in Kinsky. The results were the same as those in Bubble DS. So it seems that more than one control point is behaving in the way you suggest, and we'll have to live with what is only a fairly minor irritant unless or until that behaviour is changed.

It would be interesting to know Bubbleguuum's view if he ever reads this; there may of course be a good reason for making the recursive series of search requests. Alternatively, perhaps this was just not an issue until you came up with the concept of intelligent browsing.

David

I think you are correct on all points. With a traditional fixed hierarchy where each item can be reached by only one path, the recursive browse approach produces correct results with no duplicates.

Like you, I would be interested to hear whether bubbleguuum would consider implementing either of the approaches I described for solving this problem.

[bubbleguuum]

(25-03-2014 08:47)simoncn Wrote:  I think you are correct on all points. With a traditional fixed hierarchy where each item can be reached by only one path, the recursive browse approach produces correct results with no duplicates.

Like you, I would be interested to hear whether bubbleguuum would consider implementing either of the approaches I described for solving this problem.

I vaguely remember trying to filter out duplicates in recurse browse from MinimServer at some point.
But it was impractical because MinimServer doesn't use unique object id for the same items. The id seems to always point at where it is in the browse tree. Duplicates could be filtered out using other criterias but as there are possible unintended side effects, I didn't pursue it. And there's that refID attribute that can complicate stuff further (not used by MinimServer)...

[DavidHB]

Thank you to bubbleguuum for his swift intervention. I should like to take this opportunity of thanking him for the enjoyment I get from using the Bubble DS app.

I'm not qualified to discuss the technicalities. Clearly, there are complications, as I suspected. I hope that, between them, Simon and bubbleguuum can find a means of addressing this issue. As I said, I don't think that it's a huge problem in practical terms, but I believe that, for some potential users, it may have presentational importance.

The underlying philosophy of DNLA seems to be that the user interface has to be impoverished (and dumbed down) in the interests of consistency, reliability and minimising the costs of user support. Applications like MinimServer and Bubble DS, which use a wider range of UPnP features to provide a much richer user experience, challenge this approach. The combination of Bubble DS and MinimServer currently provides this richer experience in the smoothest form of all the applications I have tried. Any presentational glitch (even where there is no major functional problem) will too readily persuade users that UPnP-based apps are inherently difficult and unreliable, and that would be a pity.

David

[simoncn]

(25-03-2014 13:20)bubbleguuum Wrote:  I vaguely remember trying to filter out duplicates in recurse browse from MinimServer at some point.
But it was impractical because MinimServer doesn't use unique object id for the same items. The id seems to always point at where it is in the browse tree. Duplicates could be filtered out using other criterias but as there are possible unintended side effects, I didn't pursue it. And there's that refID attribute that can complicate stuff further (not used by MinimServer)...

Would it be possible to use UPnP Search (if the server supports this) to retrieve the list of tracks to add to the playlist? I think I can filter the search result to ensure it doesn't contain any duplicate tracks.