На данный момент базовая поддержка обеспечена только для устройств семейства Nexus.
Host mode
Android 5.0 (API level 21) and above supports a subset of USB audio class 1 (UAC1) features:
The Android device must act as host
The audio format must be PCM (interface type I)
The bit depth must be 16-bits, 24-bits, or 32-bits where 24 bits of useful audio data are left-justified within the most significant bits of the 32-bit word
The sample rate must be either 48, 44.1, 32, 24, 22.05, 16, 12, 11.025, or 8 kHz
The channel count must be 1 (mono) or 2 (stereo)
Perusal of the Android framework source code may show additional code beyond the minimum needed to support these features. But this code has not been validated, so more advanced features are not yet claimed.
http://source.android.com/devices/audio_usb.html
По официальному заявлению разработчиков, "аудиофильские" и мультимедийны надстройки в официальный релиз пока не входят.
Тем не менее, это значимый шаг в развитии платформы Андроид. Ранее для подключения USB Audio устройств использовались различные алгоритмы, в т.ч. официальная поддержка Accessory Mode появилась уже в Andriod 4.1:Цитата:
https://code.google.com/p/android/is...etail?id=24614
Basic features of USB host mode audio are now implemented in Android 5.0.
For consumers on Nexus devices only, see this article in English:
“Record and play back audio using USB host mode”
https://support.google.com/nexus/answer/6127700
It should be published in more languages over the next two weeks.
As noted, only selected Nexus devices support this feature.
Support on other non-Nexus Android devices is up to each device manufacturer.
For Android device OEMs, SoC vendors, USB audio peripheral suppliers,
advanced audio application developers,
and others seeking detailed understanding of USB digital audio internals on Android.
see http://source.android.com/devices/audio_usb.html
As mentioned at comment #1345 above, this is the initial support.
I know there are more use cases and features that are not yet supported
(for example "audiophile" and multi-channel).
And there are combinations of Android devices and USB peripherals that
don't work. I can't commit to supporting everything, but
I do want to increase peripheral coverage and add the most critical missing features.
As this issue is now closed, please feel free to file new issues here
for your favorite features and (class-compliant) USB audio peripherals that don't work.
Please include the exact manufacturer name and model, a link to the USB peripheral page,
a short description of which Android device you used, what you expected to have happen,
and what actually happened.
Thanks!
Accessory mode
Android 4.1 (API level 16) added limited support for audio playback to the host. While in accessory mode, Android automatically routes its audio output to USB. That is, the Android device serves as a data source to the host, for example a dock.
Accessory mode audio has these features:
The Android device must be controlled by a knowledgeable host that can first transition the Android device from development mode to accessory mode, and then the host must transfer audio data from the appropriate endpoint. Thus the Android device does not appear "driverless" to the host.
The direction must be input, expressed relative to the host
The audio format must be 16-bit PCM
The sample rate must be 44.1 kHz
The channel count must be 2 (stereo)
Accessory mode audio has not been widely adopted, and is not currently recommended for new designs.
