USB DAC support on USB OTG enabled devices

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dmitrykos
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Re: USB DAC support on USB OTG enabled devices?

Post by dmitrykos » Sat May 19, 2012 2:46 pm

Hi DanBa!

Thank you very much for a nice information regarding iOS/Android USB Hosts.
IMHO Google has very likely no idea about high dimensions music devices, but Android will very likely have a big market share in this area thanks to the compliancy with the open standards: standard USB audio, open source Linux kernel, free Android, standard DLNA, standard Wi-Fi Direct, standard Wi-Fi Display.
I agree. Google is missing a very big sector of audio consumer electronics which could be driven by Android powered devices. Looking at current audio stack implementation in Android OS the quickest and easy solution would be enabling ALSA API for user space and providing possibility to music apps to lock audio hardware exclusively. Also good thing is that Android OS is open source, so such future modifications are possible.

Best regards,
Dmitry.

Liveinthemoment
Posts: 209
Joined: Fri Feb 24, 2012 2:40 am

Re: USB DAC support on USB OTG enabled devices?

Post by Liveinthemoment » Fri May 25, 2012 1:06 am

OK some new news.

The Archos 80 G9 using the latest firmware 4.06 (not the test2) now has great sound with my USB DAC (for the first time).

It isn't stable even with the default player but particularly even less stable if not using the default player....sigh.

To use I must reboot the device, open Neutron, choose to keep screen awake all the time, and start playing THEN plug in the USB. The sound is now the same as my PC through the USB DAC.....great.

However.....it will eventually crash after only 1-5 songs and need a complete RESET (hold power for 10 seconds) before any player (even default or even video) will work again (even silent through built-in speaker).

I am hoping that Archos will update their ICS to Google's latest build in which the audio skipping was actually fixed.

Until they do that forget the USB DAC - the functionality simply does not exist in a stable form.

dmitrykos
Site Admin
Posts: 1914
Joined: Mon Apr 25, 2011 6:15 pm

Re: USB DAC support on USB OTG enabled devices?

Post by dmitrykos » Fri May 25, 2012 12:58 pm

Looks like one of the producers moved a bit closer to working USB DAC :)

DanBa
Posts: 46
Joined: Thu May 10, 2012 9:16 pm

Re: USB DAC support on USB OTG enabled devices?

Post by DanBa » Mon May 28, 2012 8:20 am

Like the overwhelming majority of factory or stock Android devices, with the exception of the Archos G9 tablet and the developer-targeted Texas Instruments Blaze tablet, the factory Linux-powered Logitech Squeezebox Touch does not support USB DACs.
http://omappedia.org/wiki/USB_on_Blaze_Tablet_with_ICS

The USB audio is enabled manually on Squeezebox Touch:
http://www.digitalaudioreview.net.au/in ... ebox-touch

The latest method uses an applet which allows a custom kernel to be installed and provides menus to select the audio output device.
This custom kernel can support 24-bit/192KHz USB DACs. It can also support asynchronous USB DACs which sound theoretically better than the legacy adaptive USB DACs.
http://www.digitalaudioreview.net.au/in ... ebox-touch
http://forums.slimdevices.com/showthrea ... mpressions


The USB audio is enabled on the Ainol Novo 7 Advanced tablet:
http://www.slatedroid.com/topic/29289-u ... -and-libs/

"We just need 3 base things:
1st: USB Host support in Android kernel.
2nd. USB audio driver, in kernel, or compiled as a module.
3rd. Some logic to switch to USB audio card, or back to internal one."


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The Google issue "Enable USB audio", requesting Google to standardize USB audio on Android smartphones/tablets, has reached the Top 9 of the Google issue rankings.
http://code.google.com/p/android/issues ... ort=-stars

Vote: Click on the star (it appears after signing in)

DanBa
Posts: 46
Joined: Thu May 10, 2012 9:16 pm

Re: USB DAC support on USB OTG enabled devices? {Please vote

Post by DanBa » Sat Jun 02, 2012 9:01 am

Apparently, the USB audio feature is enabled on factory Samsung Galaxy S III:
http://forum.xda-developers.com/showpos ... tcount=133

"I got my sgs3 a few hours ago and just plugged it into my Topping tp30 USB DAC/amp and it's playing audio through it to my speakers!!!"


Affordable hi-fi rig:
http://news.cnet.com/8301-13645_3-20058 ... =txt;title

music stored on SGS3 > SGS3 player > digital audio stream >> USB cable >> USB DAC/amp Topping TP30 >> speakers

http://www.youtube.com/watch?v=jR6Vc28N ... e=youtu.be


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Keep lobbying for the Android USB audio standardisation (i.e. USB DAC as a standard USB device, like a USB mass storage device, for Android smartphone/tablet).
http://code.google.com/p/android/issues ... ta%20%20rs

Vote: Click on the star (it appears after signing in)

dmitrykos
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Posts: 1914
Joined: Mon Apr 25, 2011 6:15 pm

Re: USB DAC support on USB OTG enabled devices? {Please vote

Post by dmitrykos » Fri Jun 08, 2012 7:56 am

Great news about SGS3 and its ability to operate with External DAC! :)

If Samsung ever decides to release API/library to access audio DAC/router directly and exclusively (skipping Android OS audio stack) from user apps then it would solve problem with hardcoded 16/44.1 format in Android OS and would bring an exciting possibilities for audio developers to provide best possible quality which hardware may handle.

DanBa
Posts: 46
Joined: Thu May 10, 2012 9:16 pm

Re: USB DAC support on USB OTG enabled devices? {Please vote

Post by DanBa » Thu Jun 28, 2012 8:25 am

"Android 4.1 for Developers
New Media Capabilities
USB Audio
USB audio output support allows hardware vendors to build hardware such as audio docks that interface with Android devices."
http://developer.android.com/about/vers ... html#media

DanBa
Posts: 46
Joined: Thu May 10, 2012 9:16 pm

Re: USB DAC support on USB OTG enabled devices? {Please vote

Post by DanBa » Fri Jun 29, 2012 1:31 am

The USB DAC recommended by Google is a new type of device. It is not compatible with PC or Mac.
http://developer.android.com/tools/adk/ ... io-support
http://developer.android.com/tools/adk/ ... play-audio

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A legacy USB DAC compatible with PC / Mac acts as a USB device, and a PC / Mac acts as a USB host.
A USB DAC recommended by Google acts as a USB host, and a Android smartphone / tablet acts as a USB device.

Personally, I prefer the legacy USB audio feature implemented by Samsung on Galaxy S III, which can interwork with a legacy USB DAC like FiiO E7 or ODAC.

The legacy USB audio feature is still specified in the Android specs:
http://developer.android.com/guide/topi ... index.html
http://developer.android.com/guide/topi ... /host.html
http://developer.android.com/reference/ ... tants.html
"USB_CLASS_AUDIO USB class for audio devices"

Solidus
Posts: 17
Joined: Sun Apr 15, 2012 4:22 am

Re: USB DAC support on USB OTG enabled devices? {Please vote

Post by Solidus » Mon Jul 02, 2012 11:02 pm

I've read that Jellybean has USB DAC support. Will report back when I get my Nexus 7 in a couple of weeks.

DanBa
Posts: 46
Joined: Thu May 10, 2012 9:16 pm

Re: USB DAC support on USB OTG enabled devices? {Please vote

Post by DanBa » Tue Jul 03, 2012 5:37 pm

An Android 4.1 Jelly Bean-powered device can have both USB audio out modes: standard USB audio out and Android-specific USB audio out.
These features are at the Android kernel level.
http://developer.android.com/tools/adk/ ... io-support

"Android Open Accessory Protocol 2.0 includes optional support for audio output from an Android device to an accessory. This version of the protocol supports a standard USB audio class interface that is capable of 2 channel 16-bit PCM audio with a bit rate of 44100 Khz. AOA 2.0 is currently limited to this output mode, but additional audio modes may be added in the future.
To enable the audio support, the accessory must send a new USB control request: SET_AUDIO_MODE"

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It should be easy to enable standard USB audio out and Android-specific USB audio out on an Android 4.1 Jelly Bean-powered device with USB host capability.

Let's keep up the pressure on Google and the Android device manufacturers for the standard USB audio out:
http://code.google.com/p/android/issues ... ry%20Stars

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