[pulseaudio-discuss] [PATCH v5 0/7] New API for Bluetooth A2DP codecs

Luiz Augusto von Dentz luiz.dentz at gmail.com
Thu Jan 24 14:12:23 UTC 2019

Hi Pali,
On Thu, Jan 24, 2019 at 11:28 AM Pali Rohár <pali.rohar at gmail.com> wrote:
> > Perhaps that was used to compensate the transmission latency, but that
> > would be different for SCO and A2DP, but I tried with just 5 ms and it
> > seems to work pretty well:
> Is is possible to retrieve (from kernel? bluez?) transmission latency?

Well that is not a fixed delay, besides PA seems to be already taking
some extra latency time into account as it does 2 times some latency I
assume that is the hardware which in this case would be the Bluetooth

> > I: [lt-pulseaudio] protocol-native.c: Final latency 100.00 ms = 25.01
> > ms + 2*24.99 ms + 25.01 ms
> >
> > As oppose to something like 140 ms which the original code produces.
> I think that adding a new function for codec API which calculates codec
> latency is the correct way how to deal with it.

Yep, indeed we need something to take into account the different
algorithm delays.

Btw, Ive send a review about the a2dp codec API but apparently it is
stuck due to its size, so someone needs to approve it. It is
suggesting some changes to the naming, etc, but I think I found a real
bug in which the endpoints hash function is used incorrectly since you
just pass the endpoint path not the struct pa_a2dp_codec_id.

Luiz Augusto von Dentz

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