Re: [Alsa-user] Bluetooth audio

[Torstein H. <he...@re...>]

On Wed, Mar 06, 2013 at 12:34:58 +0100, Thorsten Mühlfelder wrote:
> > But there are some questions left: Bluetooth A2DP uses lossy
> > compression on the audio data and only SBC codec is mandatory. AFAIK
> > some devices also can use MP3 or the new APT-X codec.
> > 1. Can I use APT-X with Alsa?
> > 2. Is the compression done by software (in the driver) or in
> > hardware (e.g. in the USB dongle)?
> 
> On some review I've read that the Apt-X compression is done in
> hardware by the BT stick and it should also work with Alsa. Is this
> correct?

I just tried this with Sennheiser BTD 500 USB and Sennheiser MM-450X,
both Apt-X capable. The BTD 500 only supports A2DP, AVRCP and HSP
Bluetooth profiles, and handles the Bluetooth stack in the USB dongle.
It only exposes a USB sound card that works fine with ALSA. According to
the led on the dongle, it uses Apt-X.

There aren't that many USB dongles with Apt-X support for sale. Creative
BT-D1/BT-W1 looks to be similar to the BTD 500, exposing only a USB
sound card. Azio BTD-V400 on the other hand appears to support other
Bluetooth profiles like DUN and FTP, and might require more software
support.


Torstein