[pulseaudio-discuss] SBC XQ for PA 13.0

[Pali Rohár]

On Monday 09 December 2019 14:47:26 Andrey Semashev wrote:
> As a user, I don't know whether I can use SBC XQ. I don't know whether its
> bitrate will fit in my radio conditions. If my device happens to support SBC
> XQ, that is the codec that will get picked upon connection. Please, correct
> me if I'm wrong, but I don't see a way to influence that.

You can ask same question for aptX-HD codec. It has also fixed high
bitrate.

> SBC XQ is high quality and high bitrate, true, but PA should adapt to the
> actual use conditions.

SBC XQ is defined with usage of one specific bitpool value.

> More so if it actually has the means to do so. If PA
> detects that SBC XQ does not fit in BT bandwidth, it should gradually drop
> quality.

Maybe we can implement disconnecting SBC XQ profile when problem happen
and connect again with SBC in Automatic quality.

But there is another problem. People who chose high quality codec do not
want to see that application itself without their instruction decide to
change codec to low quality. This is reason why non-SBC codecs are used.
Because they provide one fixed quality which is same whatever bluetooth
adapter or headphone you will use. SBC is criticized for a long time
because current implementations automatically choose some quality which
is not under user control. So for these reasons there is SBC LQ, MQ, HQ
and XQ. You can choose what you want to use. By default is automatic
mode which decreasing quality.

-- 
Pali Rohár
pali.rohar at gmail.com