iOS 18 USB DAC output sampling rate issue

[blaubär]

Proposal: add something like the "custom format" in Android to the iOs version, so that the user who knows what sampling rate his device supports can tell Neutron to use that, whatever the f...ng iOs tells.

[314N]

No. Other music player are fine with ios18 and dsd or hi-res flac files.

Did you make sure that these players really make the device put out high-res audio, not just tell you they do ? If they do: the last time the developer wrote :

Unfortunately Apple does not react on the filled bug report about broken frequency switching (http://twitter.com/neutroncode/status/1 ... 9408142789).

We reported first via paid developer support as technical question regarding how to overcome a new iOS17 behavior when requested frequency can not be readback from the device (to confirm that frequency was accepted by the destination device, it is what is actually broken) and Apple devs confirmed that iOS17 has this bug and there is no effective workaround and recommended to fill the bug report (it was done 2 months ago!). Reading back frequency is important because it is the ONLY way to find out what frequencies are supported by the destination device on iOS. In case of USB DACs it is crucially important because there are DACs which support up to 96, 192, 384 kHz and higher. Another clunky way is check device name and hardcode supported frequencies but it is no-go scenario.

Other apps can be setting frequency blindly without checking whether it was actually set (accepted) thus they more or less work. Neutron can set frequency without checking too but then how to find out what device limits are and provide correct DoP and Hi-Res PCM support?

Our advise: Please find time and fill bug report to Apple so they could hear us!

Neutron might work more cautiously with an operating system that doesn't tell it that high sample rates are supported.

Dude, I have EXTERNAL Dac. It says what kind of input signal it has. I even wrote the brand of USB above (FIIo KA17)

The quote you wrote, This is an old story that has nothing to do with my question. Beta version 18 has been available for 3 months, but the players developers apparently had no time. And now that the final release of 18 has been out, they are redirecting the problem with their program to Apple.

[blaubär]

The quote you wrote, This is an old story that has nothing to do with my question. Beta version 18 has been available for 3 months, but the players developers apparently had no time. And now that the final release of 18 has been out, they are redirecting the problem with their program to Apple.

Then I haven't yet understood your story. My story is: Neutron seems to tread carecully when the os doesn't tell what sr it supports. And I propose to add an option for the user to override this cautious behaviour if he so wishes and thinks he knows what he's doing. Anyway, try the refund if you think that's a good idea. And/or pester neutronmp@gmail.com to get a workaround.

[Kalkant]

Can anyone con firm this?

Have a look at the topic above, I merged your post into it.
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I suggest nobody update to iOs 18. If he can help it.

Thank you blaubär. Should have read this before updating to iOS 18...

[originalsnuffy]

If anybody can get this to work with Apple and IOS 18 I think it will be Dmitri. My sense is that he prefers not to use workarounds. I personally would be okay with a workaround approach.

I wonder if I can even go to 17.7 from 17.6.1 given where Apple seems to be? There are supposedly some security fixes in 17.7 that are also in 18.0

Well, anyway it would be great to see if reports have been filed with Apple.

I understand the person who is upset, but the bug really is on the Apple side. I could not even get my fallback program to work properly (EverPlay) so I know Apple has their finger in the pie again. Everplay was the only program that worked properly with DoP in IOS 17, so I was surprised that it was a dud with IOS 18. I have this information because I tried 18 for a bit only to realize that for me it was a no go as of yet. Well, no big deal on EverPlay as my preferred program is Neutron.

By the way, going back to 17.x from 18.x will cause a complete erase on the iphone. You can restore from a backup, but inevitably one has to put in a bunch of passwords anyway. And redownload one's music, etc.

[314N]

Yes, EverPlay is not working on iOS 18, But - Scylla (flac, dsd) - is still working, DS file (flac) - is still working ( Maybe someone will need a backup player for this time). So, It's not all that bad. And if some players continue to work, then it's possible. If anyone knows exactly which player works with high res and dsd with iOS 18 - write here.

[dmitrykos]

Neutron Player (and Recorder) is using Apple's API - AVAudioSession::setPreferredSampleRate() to query the supported sample rates of the connected device. It stopped working in 17.0, was fixed in 17.3 but for USB DACs only (although I was telling Apple that they did not fix it completely for the phone's hardware which supports selection between 44100 and 48000 Hz but it was ignored), now broken again in 18.0.

Apple really must have to fix their API. If they do not (I can't imagine why) then the only wayout is - provide possibility similar to Custom Format in Android (as mentioned earlier) and set the list of supported frequencies. But, what if you have 2-3-4 DACs (or USB headphones) with different hw capabilities.

The best for all who have not yet updated to iOS 18 is to hold on with the update and stay on stable iOS 17.7. iOS 18 is currently having many bugs, there is ongoing 18.1 beta already. I think it is not the end.

From Neutron's side - submitted bug report to Apple again. They fixed it in 17.3 and it took 6 months (from 17.0 release). Maybe it will be faster now. You, as Apple users, can also submit bug reports to Apple. The more reports they get the more important bug becomes and the quicker they will fix it, so please report to Apple actively about this issue. Just claim that you lost hi-res output capability for the connected USB DACs, mention Neutron Player and other similarly misbehaving apps you know.

Here is doc about broken API:
https://developer.apple.com/documentati ... guage=objc

Broken behavior is this: "This method requests a change to the input and output audio sample rate. To see the effect of this change, use the sampleRate property.". sampleRate property does not return the expected value.

[originalsnuffy]

Dmitri,

Thank you for the helpful post. So I gather that 17.7 does not have any issues?

I have filed my own bug report with Apple and I encourage everyone else to do so.

Crossing my fingers that a new release will fix the returning bug.

[dmitrykos]

> Thank you for the helpful post. So I gather that 17.7 does not have any issues?

Yes, just double tested - still works fine on iOS 17.7.

[originalsnuffy]

I will stay with 17.x for now.

Will Neutron admin let us know when it is "safe" to go to the 18.x series? Looking for the sampling rate handshake issues to be resolved so HiRes PCM and DSD work again. I don't want to restore my phone again so I will hold off until I hear things are a go.