Enable USB audio

DanBa

Member
Feb 11, 2012
2
0
If you want the USB audio enabled on any Android 4.0 device via official firmware/kernel, please vote (aka star) here:
Issue 24614 - android - Enable USB audio on the Galaxy Nexus (or any Android 4.0 device) - Android - An Open Handset Alliance Project - Google Project Hosting


Star: Vote by clicking on the star






According to Android specifications, Android 4.0 devices could support the USB audio feature, i.e. Android 4.0 devices and USB_CLASS_AUDIO compliant devices like standard USB DAC could interoperate:
USB Host and Accessory | Android Developers
http://developer.android.com/reference/and...bConstants.html


USB_CLASS_AUDIO compliant devices like standard USB DAC don’t need a special USB device driver. Instead, they use an operating system standard driver.
The Android standard USB audio driver is the generic USB Audio Driver for ALSA (Advanced Linux Sound Architecture).
And the latest Android 4.0 includes “card.c“, the USB Audio Driver for ALSA which should be compliant with USB audio class 2 devices allowing for 24 bits / 192 kHz.
https://bitbucket.org/paulobrien/android_ke...ound/usb/card.c


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Android relies on Linux version 2.6 for core system services such as security, memory management, process management, network stack, and driver model. The Linux kernel also acts as an abstraction layer between the hardware and the rest of the software stack.
Thus Android handles all the things that Linux is really good at such as a vast array of device drivers, which take the pain out of interfacing to peripheral hardware.




Most USB DAC work without special USB device driver on PC, Mac and hopefully Android 4.0 devices with USB audio enabled.


Some USB DAC:


. Portable FiiO USB DAC/amp:
FIIO-Amplifier


. Portable iBasso USB DAC/amp:
iBasso


. Portable RSA USB DAC/amp:
Emmeline "The Predator" Portable USB DAC/Amp - Ray Samuels Audio


. Portable HeadAmp USB DAC/amp:
HeadAmp - Audio Electronics (pico USB DAC/Amp)


. Portable GoVibe USB DAC/amp:
Jaben Online Store


. Desktop CEntrance USB DAC/amp:
CEntrance -> Products


. Desktop USB DAC MSB DAC IV:
List Prices


....






About external USB DAC/Amp


A digital audio system is composed of:

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. A storage module: Music is stored in file as a series of bits 0 & 1 with different encoding formats (MP3, WAV, FLAC…).
. A player: The player decodes the bits 0 & 1 to PCM digital audio signals.
. A DAC (Digital to Analog Converter): The DAC converts the PCM digital audio signals to the original analog audio signals.
. An amplifier: The amplifier amplifies the analog audio signals.
. A speaker: The speaker restitutes the music.


Like a PC or a Mac, an Android phone is a digital audio system.

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Hopefully, the Android phone, running on a kernel with a USB audio driver, can output the PCM digital audio stream to an external standard USB DAC & amplifier & headphone, much more efficient than the internal DAC & amplifier & speakerphone.

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