Is music played via USB or Bluetooth?

[variab1e]

Is Music Played via USB or Bluetooth

With Android Auto is the music played back via the bluetooth connection or USB? I've read the Pioneer docs and it does say that Phone calls are handled via Bluetooth, but I was hoping that didn't mean music was as well. Music over bluetooth in my experience sounds quite bad with compression and narrow bandwidth, whereas with USB I would hope it would be played in the source format, ie. 16bit/48khz. Anyone know the answer to this?

Thanks!

 

[Cant Miss]

Re: Is Music Played via USB or Bluetooth

It is over USB media.

 

[variab1e]

Perfect! Thanks, is the sound noticeably clearer then bluetooth I take it?

 

[mikereidis]

All audio is over Bluetooth on my 4100NEX, at least with the first release of Android Auto I tested, and a few subsequent where I sniffed the USB. Turn BT off and audio stops.

I reverse engineered the AA protocol and built a Headunit app: [Android 4.1+] Headunit for Android Auto - 150612 June 12 - Release #4: Auto-Start - XDA Forums

I think (and hope) that audio over USB is possible with AA but haven't tried yet.

BT Audio may be a limitation of Pioneer headunits; others may work over USB.

 

[Cant Miss]

Re: Is Music Played via USB or Bluetooth

It may depend on the phone. I can tell you that with a Moto X 2014, it plays over USB.

 

[variab1e]

Re: Is Music Played via USB or Bluetooth

Cant Miss, how can you tell it is via USB rather than BT?

 

[Cant Miss]

Re: Is Music Played via USB or Bluetooth

Cant Miss, how can you tell it is via USB rather than BT?

I can still hear Pocket Casts when BT is not connected, and I remember seeing something on my phone indicating it was 'connected to USB media' (IIRC, it was a notification). Unfortunately I can't double check the notification at the moment as my Moto X is on its way back to Motorola due to a screen issue.

 

[mikereidis]

Re: Is Music Played via USB or Bluetooth

I can still hear Pocket Casts when BT is not connected, and I remember seeing something on my phone indicating it was 'connected to USB media' (IIRC, it was a notification). Unfortunately I can't double check the notification at the moment as my Moto X is on its way back to Motorola due to a screen issue.

Hmm, I guess that's USB DAC support, likely the rarely used Android Open Accessory Protocol type.

I know that when the HU does not support an audio service (like my HU app), audio comes from the phone. From there it can be sent via phone speaker, wired headset, BT if connected somewhere, or USB DAC is available via that.

I'll look into that.

 

[Cant Miss]

Re: Is Music Played via USB or Bluetooth

I'll look into that.

BTW, congrats on the AAA spot!

 

[mikereidis]

Re: Is Music Played via USB or Bluetooth

BTW, congrats on the AAA spot!

You mean "All About Android" ? Just found it now. Video starts about 56:30 : https://twit.tv/shows/all-about-android/episodes/218

I re-read the docs on accessory mode audio; there's a bit here: https://source.android.com/accessories/aoa2.html#audio-support

So it may be 44.1KHz, 16 bit stereo output only. But that's better than standard Bluetooth I think.

There may not be microphone input/voice over USB if it's Android open accessory compatible.

 

[Cant Miss]

Re: Is Music Played via USB or Bluetooth

There may not be microphone input/voice over USB if it's Android open accessory compatible.

Makes sense as AA hardware has dedicated mic input.

 

[mikereidis]

Re: Is Music Played via USB or Bluetooth

OK, I think I've finally seen Audio over USB with Android Auto on my Nexus 7 2013.

But AA seems VERY insistent on turning Bluetooth on. If I turn if off, AA turns it back on and reconnects to 4100NEX.

I could only get (or prove ?) audio over USB by hitting the 3 BT device limit the 4100 has for number of paired BT devices. Audio output worked, but I couldn't get audio voice input to work.

The 4100 in this state keeps showing BT pairing errors and I have to hit Mode twice every 20 seconds or so to get touch access to AA.

My HTC One M8 can't do this. To see if a phone can output audio over USB with AA, from adb shell run "cat /system/etc/audio_policy.conf". If there's a section containing "usb_accessory" like this, it should work:

usb {
outputs {
usb_accessory {
sampling_rates 44100
channel_masks AUDIO_CHANNEL_OUT_STEREO
formats AUDIO_FORMAT_PCM_16_BIT
devices AUDIO_DEVICE_OUT_USB_ACCESSORY
}

 

[Cant Miss]

Re: Is Music Played via USB or Bluetooth

AA seems VERY insistent on turning Bluetooth on.

Not just insistent... psychopathic.

If I let my phone connect to the bluetooth on 4100 before plugging it in, everything is fine. But if it is plugged in before starting the vehicle it connects via a new pairing. If I stop the car to get gas, upon starting it again it sets up a new pairing. I know this because when I eventually unplug the phone after a number of stops I see a bunch of notifications about a new paired device... you know, the ones asking about making it a trusted device.

Under these circumstances, I have even seen the 4100NEX pairing vanish from the bluetooth pairings screen entirely.

The only way I have discovered to maintain the original pairing (and trusted device), is to disconnect the phone after stopping the car, and then upon starting the car, wait for the bluetooth to connect, and THEN plug in the phone. This is very bizarre behavior compared to the bluetooth always connecting via the existing pairing when not using Android Auto.

Something in Android Auto is so aggressive about making sure bluetooth is on, and paired, that it creates a new pairing even when a valid one already exists. I see this as a bug, or at least a questionable design decision.

 

[Jkissxx]

On my PIONEER AVIC F70 you can play music through blue tooth from my LG G3.

 

[Pedrore]

But we're talking about Android Auto here, which uses USB for media playback at higher fidelity than bluetooth. AFAIK, for a unit to be branded as supporting Android Auto this capability is required and it's also one reason Android L is mandated.

http://forums.androidcentral.com/an...ons-thread-ask-us-anything-9.html#post4394134

 

[theelite1x87]

But we're talking about Android Auto here, which uses USB for media playback at higher fidelity than bluetooth. AFAIK, for a unit to be branded as supporting Android Auto this capability is required and it's also one reason Android L is mandated.

http://forums.androidcentral.com/an...ons-thread-ask-us-anything-9.html#post4394134

I found this thread via Google search trying to find an answer myself. I believe I figured it out, thought I'd share. I just bought a 2016 Hyundai Sonata which obviously has android auto. I was wondering why the audio was sounding terrible with the car. It was boomy and a lack of real bass or clarity. No what I expected from the upgraded audio system. I assumed android auto was using USB and thought nothing more of it. But I checked my Bluetooth. When paired with the car, it was checked for phone calls and media usage (under the paired device settings, I'm using a LG g4). I unticked media playback and left phone usage. I have no usage for Bluetooth audio at all. I only care about phone calls as far as Bluetooth is concerned. The music cut out for a split second once I disabled it but then came back. The audio quality difference was undeniable. It was clearly playing over USB now and was in fact using Bluetooth for audio previously. Bass was nice and deep. Boomy speaker syndrome gone and highs where nice and crisp. Not sure why it prioritize Bluetooth playback over USB but it did. The odd thing is that I re-enabled Bluetooth media playback later, but it never went back to Bluetooth as the media transfer. It's staying on USB (I can tell from the audio quality). Not sure why it behaved like this but whatever. Bluetooth for phone usage is still working as expected. Only thing is with media playback disabled you can't stream wirelessly to the head unit. You have to use android auto for music (or old fashioned aux jack). But if you got android auto, you probably don't care. So, yeah. Android auto does use USB for audio. But check your settings as it might want to send it over the (forced...) Bluetooth connection anyway.

 

[CrashAlpha]

Re: Is Music Played via USB or Bluetooth

By now you guys know AA uses USB Audio. The problem is that some Samsung mobiles have problems with it. It plays back at very low volume. I have been looking all over for help troubleshooting USB Audio, including AA support on Twitter. Nothing. This is actually the first thread I have read on USB Audio, AA or otherwise. Does anyone have any clue how to troubleshoot USB Audio, tweak the settings?

Posted via the Android Central App

 

[theelite1x87]

Probably a software problem with the phone. My understanding is that when using usb audio, it's just sending the raw digital data. No volume amplification. Im using a LG G4 and with AA over usb, I have no control over the volume. Volume is adjusted only via the cars receiver. I imagine the usb is suppose to act like a fixed "line level out" but digital. I'll try to fiddle with my phone but I don't think you're suppose to be able to control volume level with it.