[pulseaudio-discuss] [PATCH v13 10/10] bluetooth: policy: Treat bi-directional A2DP profiles as suitable for VOIP

Tanu Kaskinen tanuk at iki.fi
Thu Oct 31 13:02:01 UTC 2019

On Mon, 2019-10-28 at 17:12 +0100, Hyperion wrote:
> - Bluetooth packet size is not constant : BT traffic is splited in radio slots 
> that have fixed time lengh : so for a given bandwidth : slots size vary

It's still not clear to me whether the bluetooth packets have constant
size within one A2DP stream or not. Pali wrote earlier:

    For established connection, bluetooth packet size is fixed. SBC
    packet size depends on SBC bitpool (and other) parameters. And
    because pulseaudio does not support generating fragmented SBC
    packets, it can only fill those SBC frames which fits into
    bluetooth packet size.

That sounded like reducing the bitpool and therefore the SBC packet
size mid-stream wouldn't help, because the lower level bluetooth packet
size is constant for the duration of the stream. However, if the
bluetooth packet size dynamically reacts to changes in the SBC packet
sizes, then reducing the bitpool mid-stream is useful. Can someone
confirm which it is?



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