Android Mobile - "Exclusive USB Audio Access Mode" option for DACs

[Richard Branches 330]

I noticed the following when using the Emby for Android app along with a FiiO KA1 USB DAC:

When a 44.1Khz or 48Khz song is playing and the next one is a 88.2Khz and higher, the DAC changes the RGB led from blue to yellow, indicating the quality playing. So far so good.

The problem is, when a 88.2Khz and higher song is playing and the next one to play is a 44.1Khz or 48Khz, the DAC doesn't change from yellow to blue, it gets stuck in yellow, so the quality of the song gets affected, even the volume level is a bit lower than it should, the only way so far to fix it is to stop or pause the song and resume it.

Please let me know if you need a log.

[Richard Branches 330]

Looks like this is not an issue of the Emby app but a global issue when the "Exclusive USB Audio Access Mode" is not being used since the app never asks for it, I don't have this issue with USB Audio Player PRO because it always asks for that.

I will have to consult this with FiiO.

Edited April 20, 2023 by Richard Branches

[Richard Branches 330]

Please delete this comment.

Edited April 21, 2023 by Richard Branches

[Richard Branches 330]

So the problem is basically that the Emby app lacks an "Exclusive USB Audio Access Mode" option and instead it's using the Android driver, therefore, please move this topic to the "Feature Requests" section, because the only solution is to implement that mode in order to bypass the Android audio stack to output audio directly to the connected USB audio DAC.

Thank you.

[Luke 42077]

Thanks for following up.

[Richard Branches 330]

Please delete this comment.

Edited April 21, 2023 by Richard Branches

[Richard Branches 330]

This is the permission the Emby app should ask anytime a DAC is connected to the phone, I really hope this gets implemented, the audio quality between using a DAC this way vs when using the Android driver is incomparable:

 

Edited June 4, 2023 by Richard Branches

[Richard Branches 330]

Android 14 will supposedly provide support for direct USB DAC playback along with the "bit perfect" playback, therefore, below is the available documentation about it, I hope that you guys take a look at this and implement the API in the Android app, I will be more than happy to test it out with my DAC and provide support once I get a phone with Android 14 of course:

Preferred mixer attributes on USB devices:

https://source.android.com/docs/core/audio/preferred-mixer-attr?hl=en

AudioMixerAttributes:

https://developer.android.com/reference/android/media/AudioMixerAttributes

[Richard Branches 330]

Looks like the "bit-perfect" feature can be tested on any Android phone with Android 14 despite Google statement that it needs to be "turned ON" by each OEM in order to work, therefore, there is an app which it seems to be the first one supporting the feature, the app is called Omnia (https://play.google.com/store/apps/details?id=com.rhmsoft.omnia) and I was able to test it out on my Moto G34 with Android 14 and my FiiO KA1, at first it didn't work but I contacted the developer and after testing several builds the bit-perfect feature finally works.

Currently, the app upscales or resamples everything to the maximum resolution that a DAC supports but that is better than getting everything resampled to 48Khz, the developer will continue working to improve the app until every song plays in its native resolution.

All this mean that you guys can start the development of this feature in the Emby for Android app and I will be more than happy to test it out for you and provide feedback.

Note: for those interested in testing Omnia, please wait until the developer releases the final build with the implementation that works correctly, it should be version 1.7.2 or higher.