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Forum: VirtualDJ Technical Support

Topic: Some Tidal tracks previously saved in vdj playlists now reuturn an "Unknown stream type" error
I've got a number of tracks saved in playlists within Virtual DJ from Tidal. These tracks have played fine in the past week or so, however since today they've startd returning an "Unknown stream type" error when attempting to load them onto a deck.

The tracks still exist in the Tidal catalogue if I browse for them, but it definitely looks like a different "version" as all my cue points are gone, even though it is, for all intents and purposes the same track (even from the same album).

Is this just a case of Tidal silently changing the track in some back-end database and giving it a new track ID and my saved-in--vdj-playlist version now pointing to a track ID that is no longer valid? Meaning the change would be seamless to those playing tracks through the Tidal software (assuming they handle the change silently), but a breaking change for those calling the API with specific Track IDs?
 
Posted Sat 16 Nov 24 @ 11:05 pm
 
I also note that these tracks seem to have some kind of gost track when searching the Tidal catalogue from within Virtual DJ. Loading the ghost returns the error, loading the valid-looking track works, but is a "different" track (at least in the Track ID / version sense) to the one in my playlist (based on the fact that the cues missing). Image below:
 
If you still have one like that in your playlists, could you check the Tag Editor and let us know the full id of the track?
 
martyghen wrote :
Is this just a case of Tidal silently changing the track in some back-end database and giving it a new track ID and my saved-in--vdj-playlist version now pointing to a track ID that is no longer valid? Meaning the change would be seamless to those playing tracks through the Tidal software (assuming they handle the change silently), but a breaking change for those calling the API with specific Track IDs?


Yes, Tidal sometimes “upgrade” a track, I assume it is for better resolution. And they don’t even handle it in their own software. I fairly often see greyed out tracks in my Tidal playlists that won’t play. But I can search them out and replace the greyed out ones in the playlists.

I wish they would make the old track id in the database an alias for the upgraded one, like a forwarding address. As it is now, it seems they leave dangling references behind when upgrading a track. This would also eliminate the issue in VDJ and other API clients.
 
Adion wrote :
If you still have one like that in your playlists, could you check the Tag Editor and let us know the full id of the track?


Sure thing! Here's one (td365215936) ...
 
Niels (cph) wrote :
I wish they would make the old track id in the database an alias for the upgraded one, like a forwarding address. As it is now, it seems they leave dangling references behind when upgrading a track. This would also eliminate the issue in VDJ and other API clients.


Agreed!
 
Okay I've done a bit more troubleshooting on this and think I've found the conditions under which the error happens:
- You have a track that has been cached previously (see note 1 below)
- That track is no longer in the cache, but you have it in a local Virtual DJ playlist, Tidal playlist, or search Tidal for the exact track
- You attempt to load the track onto a deck and get the "Unknown stream type" error (see note 2 below)
- BUT you can right click on the track on the deck and "Download to cache"; do that
- Clear the error and failed track from the deck
- Wait for the cache to finish
- Attempt to load the track again (from the exact same track in your playlist that didn't work earlier)
- The track now loads

Sometimes it gets even more strange though, because when you navigate away from that playlist, and then go back to it, the track can sometimes lose its name (and just show the track ID), or sometimes lost its waveform preview, or other data. Then when you try and load it again from the same track in the same playlist that worked above after the cache download, you get the "File not found" error. But if you navigate to the cache directly and load it from there, it works.

And throughout all of this it appears to be the same track from the very begining, still with all of your cue points and the same track ID showing the whole time in the information panel.

So I think there must be some situations where Virtual DJ's record of what is and is not cached and the associated track pointers are not playing nicely with one another (and DRM might be coming into the mix somehow as well).

---

Note 1: It has to be a file you cached and removed some time ago, like a couple of weeks; this error doesn't occur if you try and just cache a track now, remove it, then load it within the space of a few minutes. It works fine then. I haven't figured out the exact timing that makes this a problem. Though the fact that time plays a role makes me wonder if it's something to do with DRM and the cache?

Note 2: When you load the track from a Tidal search or Tidal playlist (as opposed to a local Virtual DJ playlist) then you get the "Track not found" error immediately instead of first getting the "Unknown stream type" error.
 
Adion wrote :
If you still have one like that in your playlists, could you check the Tag Editor and let us know the full id of the track?


Okay I am confident that there is some edge case bug in relation to caching of tracks from Tidal whereby some logic is not covered.

In addition to the above notes, there are some circumstances where a track can NEVER be accessed again from Tidal, with VDJ reporting the "File Not Found" error no matter what I do, even though the file exists with 100% certainty (determined by liking the Album on Tidal through their app, and then loading that exact file from the liked albums section in Virtual DJ).

If I then go and delete the Tidal related cache and library folders from C:\Users\_username_\AppData\Local\VirtualDJ the error goes from "File Not Found" to this (despite being online and other tracks loading just fine)...