Re: Support for the Bluetooth subband codec (SBC)

[Marcel Holtmann <marcel@holtmann.org>]

Hi Jaroslav,

> > besides the Bluetooth headset/handsfree support there is another type of
> > audio support. It is the high quality audio (A2DP) for headphones and so
> > on. To include a native support for these devices with every Bluetooth
> > adapter (for example the ones built into your notebook) it is necessary
> > to support the subband codec (SBC) from Philips. The codec description
> > is in the Advanced Audio Distribution Profile (A2DP).
> > 
> > I am not an audio expert and far away from doing any codec specific
> > things, but from my understanding the ALSA kernel part should be
> > extended with the SBC type for PCM devices and the library should know
> > how to convert any PCM data into the SBC format so we can use it inside
> > the kernel in a A2DP driver.
> 
> Any datasheet for this format? Anyway, if SBC format only encapsulates 
> linear PCM samples to packets, then it should be handled in the driver 
> like the USB driver does.

the datasheet for this codec can be found on the Bluetooth specification
webpage (www.bluetooth.org/spec/). It is part of the A2DP document. I
think you need to be logged in to get it and so I will send it to you in
a private mail later.

I don't think that this is linear PCM, but actually I am no expert when
it comes to codec specific stuff. I would be great if you can take a
look at it and tell me what you think how we should support it.

Regards

Marcel




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