Hi Sathish, On Tue, Mar 27, 2018 at 9:39 AM, Sathish Narasimman <nsathish41 at gmail.com> wrote: > Hi Tanu, > > > On Sat, Mar 17, 2018 at 1:26 AM, Tanu Kaskinen <tanuk at iki.fi> wrote: >> >> On Thu, 2018-03-15 at 14:49 +0530, Sathish Narasimman wrote: >> > Hi, >> > >> > I would like to know the PulseAudio module that is responsible for >> > pushing >> > the audio for every 1 millisecond. >> > >> > For NBS the packets are pushed with 48bytes and 1milli sec interval. >> >> Where does this 1 ms interval come from? The audio that pulseaudio >> writes with SCO is mono, 16-bit, 8000 Hz. With that specification 48 >> bytes means 3 ms packets, not 1 ms. >> >> > But for WBS the timing between 2 SCO packets needs to be *7.5 Milli >> > Sec.* >> > >> > *May I know how to change the packet interval between the 2 SCO >> > packets.* >> >> The write_block_size variable in src/modules/bluetooth/module-bluez5- >> device.c controls how big packets pulseaudio writes. That in turn is >> calculated based on write_link_mtu, and that comes from the transport >> acquire() callback. The ofono backend always returns 48 bytes. The >> native backend returns 48 bytes by default, but it can also be >> configured to ask the kernel what the real MTU is. >> > > I am able to set the MTU to 60 bytes in the and able to make the SCO > connection. > But still, the data rate is maintained as 1 msec. > > Do we need to introduce any latency in the PA? > As per core spec 5 , Vol 4 Part B of USB transaction the HCI packet interval > need to be 7.5msec. > Do we need to maintain the rate in PA? I suspect something in btusb.c might be the problem: https://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next.git/tree/drivers/bluetooth/btusb.c#n1272 Either the interval of endpoint is wrong or we shouldn't set the ASAP flag since that might ignore the interval completely. >> >> -- >> Tanu >> >> https://liberapay.com/tanuk >> https://www.patreon.com/tanuk >> _______________________________________________ >> pulseaudio-discuss mailing list >> pulseaudio-discuss at lists.freedesktop.org >> https://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss > > > > _______________________________________________ > pulseaudio-discuss mailing list > pulseaudio-discuss at lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss > -- Luiz Augusto von Dentz
