[pulseaudio-discuss] [PATCH v9 0/8] Bluetooth A2DP codecs

Georg Chini georg at chini.tk
Wed May 1 09:36:40 UTC 2019

On 01.05.19 11:09, Pali Rohár wrote:
> On Tuesday 30 April 2019 12:42:28 Luiz Augusto von Dentz wrote:
>> 1. At least Android seems to prefer aptX-HD but that doesn't seems to
>> produce any audio, in fact it crashed a few times so either have to
>> find out why aptX-HD is not working or don't include it.
>> 2. Codec switching with Android always seems to timeout.
>> 3. There seem to be some regression with loopback module, there seems
>> it always produces some glitch when resuming (during the playback it
>> seems alright):
>> I: [alsa-sink-ALC293 Analog] module-loopback.c: Dropping 17414 usec of
>> audio from queue
>> I: [alsa-sink-ALC293 Analog] module-loopback.c: Dropping 20317 usec of
>> audio from queue
>> I: [alsa-sink-ALC293 Analog] module-loopback.c: Adding 30657 usec of
>> silence to queue
>> I: [alsa-sink-ALC293 Analog] module-loopback.c: Dropping 105170 usec
>> of audio from queue
> Can you send btmon/wireshark dump? I can inspect aptx HD packets if
> decoder can correctly decode them.
Those messages from module-loopback are normal and expected.
They just show that module-loopback is adjusting the initial latency
to what is requested. If the source or sink is not ready when the
loopback starts processing data, it means that either the latency
will grow (if the sink is not yet accepting data) or shrink (if the
source is not yet providing data). Module-loopback tries to
compensate by dropping samples or inserting silence.

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