Problems with Mosaic in iOS version

I am having a problem with Mosaic running on an ipad air 2.

In UPnP mode it is very sluggish loading data from the server. I will get an immediate response for, say. the first 25-50 albums in album view. Then I can watch the next few albums load slowly ( around 2 or 3 a second) and as I try to scroll onwards, each piece of text data is slowly followed by the artwork thumbnail. A little later the entire application hangs.

I might have pointed the finger of blame at the hopeless Twonky UPnP server that I temporarily have but I do not have this problem using the Android version of Mosaic on my Samsung Galaxy 7 phone.

I have tried reinstalling Mosaic twice but after running faultlessly for a while the above problem reappears.

Any ideas?

I can give you a little insight into what is going on behind the scenes and that will at least explain the behavior, but the root cause may be a little more elusive.

First, it’s important to point out that all media browsing operations (regardless of service) happen on the Mosaic Processor in your dCS device. Mosaic Control is simply a front-end to those operations. That means that when you’re browsing your UPnP server all of the actual work is being done by your dCS device, not Mosaic Control.

The browsing lists are sourced from the Mosaic Processor on your dCS device. Artwork is fetched directly from the UPnP server by Mosaic Control.

When a browsing list is requested we use a lazy loading mechanism to fetch a small number of entries (40) and then request the rest of the list items in 40 entry chunks as you scroll through. This mechanism is fast and avoids the waste of resources that would be seen if the entire list was requested at the start.

The delay that you are seeing is a result of Mosaic requesting the second 40 item page from the server. There should not be any delay here so what you are seeing is not normal.

Unfortunately, this is a behavior that I have not encountered and I use similar iPad devices on a daily basis (specifically air 1 / air 2 / mini 2). Given the way that the entire process works and the fact that you aren’t seeing the same issue on Android narrows things down quite a bit.

  • Resource issue on the Mosaic Processor – This would impact Android as well, but with a transient issue that could just be a matter of timing.
  • Network issue between iPad and UPnP server – This would account for the behavior due to a delay in loading artwork thumbnails. Again the fact that Android isn’t having issues suggests that this has a low probability, but there are cases where different devices will interact with a network in different ways due to differences in hardware and operating system network stacks.
  • Resource issue on iPad – There’s a good chance that some other process or activity on the iPad is chewing up resources and this is having a negative impact on Mosaic Control. iOS is very good at isolating apps from each other, but some background tasks can eat up more than their fair share of resources.

Here’s what I recommend you try:

  1. Power-cycle your dCS device. Although I don’t think that a resource issue on the Mosaic Processor is the root cause this is worth trying.
  2. Reset your iPad – Close all apps on the iPad (double-tap the home button then swipe up on each app shown). Now hold down the power button and the home button until the iPad reboots and shows the apple logo on the screen. This means holding the controls down through the “swipe to power off” screen until you get the white apple on the black background. This will reset the OS and all running processes.

Out of curiosity, how many albums are in the list that you are trying to view?

Have had issues when trying to use Mosaic on either/both iPad and iPhone (IOS and apps are current). Launching I see the app trying to find the dCS Upsampler/DAC. The Vivaldi 2.0 app has no problems. I delete / reinstall the app (no help there), restart the iPad (again no help) and finally power cycle the Upsampler. Latter initially does not help but after a few further launch attempts (like old NASA rockets) I finally get “off the launch pad”. Any ideas?

Andrew, thank you for such a full and interesting response.

Your kind suggestion to reset the i-pad set me experimenting and the solution seems, so far, to simply be to start a Mosaic session after powering off and rebooting the i-pad rather than from sleep.

In answer to your question I am only loading a comparatively small music library of around 600 albums. However I am adding around 50 a week as the Network Bridge/Mosaic Control combination has encouraged me to get back into a heavy programme of ripping. Only another circa.1200 to go :frowning_face: The rest are SACDs so no chance of ripping them as much of the free software that was developed to enable it with certain players has now been removed from the internet ( if you could get hold of the specified player in the first place). The links exist but are dead.

Now this is very illuminating Andrew.

It is highly relevant to a limitation of Mosaic I posted on Feb 4 in the Mosaic feature requests thread. I use the ‘Album’ tag in classical music for individual works. I have a large library so for example in my ‘Classical - Modern’ genre I have 3600 albums. To make browsing manageable I use the alphabetical listing option in MinimServer however I still get a blank screen for 1 or 2 seconds while browsing as the listing catches up. I had assumed that this was due to buffering issue in the Mosaic app running on my Android tablet (no other apps running concurrently) and increasing the buffer size there could solve the issue but your explanation indicates it occurs within the dCS hardware (on my Network Bridge).

Not of any particular impact on this thread but I amazed to see that last year I only had 600 albums on my server! Around 1400 now. They are bona fide albums though so had I saved the contents as works I would guess that our collections are not dissimilar in actual size. My problem over ripping SACDs was solved by buying a Rossini transport. And the Network Bridge has been replaced with a Vivaldi Upsampler.

That more than doubling the size of the library on the server has not increased the loading time of albums into Mosaic which is visually virtually instant and I never see a blank screen ( yes I also use the alpha listing option via MinimServer).

Hello,
the stability of DCS Mosaic for IOS is unakceptable. Streaming data once I can start it works very stable. Both when I use Roon and Minim Server together with DCS Mosaic. No breaks. The problem I emphasize once again concerns the stability of DCS Mosaic. Usually, before I can choose what I want to listen to, DCS Mosaic closes several times. I have to click the icon on the phone desktop again and start all over again. Source selection, UPNP server selection etc. These are a few steps and each time Mosaic can disappears. If this helps, my wife will record what it looks like on the video. I’m just afraid it won’t help.
Best Regards Robert Tota

To put the limitation I’m experiencing into a more detailed context here’s an example:

In Mosaic I choose a Genre: ‘Classical - baroque’ (one of my own creations) then taking advantage of the alpha listing facility in MinimServer I choose ‘B’. This has 2200 albums (works in my tagging setup) with 8600 tracks. The music files are stored on the NAS in the standard(?) flat-form database Artist>Album>track.
I have no idea how the sorting algorithm in Mosaic works but I can see that to extract and display the required information from a library with 13700 albums having 4000 artists could be time consuming. The behaviour I see strongly suggests that a relatively small buffer is being used so that it has to be cleared (displayed) before the next stage of the search/display can progress. In my early days when I did assembly-language programming for real-time systems I remember using rolling buffers to cope with this type of situation.

Since yesterday it’s been a complete tragedy … … Despite being reinstalled from Appstore twice, the application closes immediately after it starts. Is there anything else I can do. Currently DCS Mosaic cannot be used because it cannot be started. Please help.
Nothing in my system has changed. The network configuration is also the same. Roon works as it worked very stable.
Regards Robert Tota

As I have been saying for months there is nothing wrong with Mosaic and its stability in either iOS or Android version. Every person who owns a Network Bridge, Bartok, Rossini or has the Vivaldi Upsampler has an identical copy of Mosaic. You are the only person with the problem that you describe. I thought that Munchoba had the same issue but you have said it is not similar and, in any case, he has more or less concluded that there is no problem with Mosaic but with his wifi.

So what alternatives are there ?

  1. App Store is sending a uniquely corrupted copy of Mosaic that they reserve for you personally :wink: .
  2. There is some fault with your i-pad/phone that means that Mosaic is not installing correctly.
  3. There is a fault with your i-pad/phone that means that the Mosaic commands sent from it are not being interpreted correctly by the server. However more likely when commands and responses are garbled is where users are running non-supported UPnP servers i.e. other than MinimServer. However that wouldn’t obviously shut down Mosaic.

However there is a further complication that relates to your need to use VoiceOver. From my own brief experiment of using it there is a possibility of various errors occurring with this feature particularly where the character showing on the screen is an icon and not text. However you are a practised user and can no doubt cope with it far better than I did. Nevertheless doubts remain . I remember that the first issue I read from you concerned the need tor dCS to take account of blind customers using VoiceOver in future revisions of Mosaic.

  1. There is some kind of problem with your network or its configuration. Of all issues which are posted on this forum as being Mosaic faults almost all turn out to be network problems in practice. It looks to me as if Mosaic and the server are losing communication over and over again and that type of issue is virtually always a network fault. So this is where I think you should concentrate your attention. I do not hold up myself as any kind of expert on networks but , given the right information, someone like Anup or the dCS staffers who post here may be able to offer a solution.

This is true. I am the only person who has a problem with DCS Mosaic. And I’m the only person using Voice Over to support IPhone and Mosaic. Maybe it is using Voice Over (it’s a screen reader built into IOS) that causes my problems. Because it seems to be the only difference. I would like my wife to run Mosaic without VO and see what happens.
Regards Robert Tota