<div dir="ltr">Hi Tanu,<div><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Sat, Mar 17, 2018 at 1:26 AM, Tanu Kaskinen <span dir="ltr"><<a href="mailto:tanuk@iki.fi" target="_blank">tanuk@iki.fi</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">On Thu, 2018-03-15 at 14:49 +0530, Sathish Narasimman wrote:<br>
> Hi,<br>
><br>
> I would like to know the PulseAudio module that is responsible for pushing<br>
> the audio for every 1 millisecond.<br>
><br>
> For NBS the packets are pushed with 48bytes and 1milli sec interval.<br>
<br>
</span>Where does this 1 ms interval come from? The audio that pulseaudio<br>
writes with SCO is mono, 16-bit, 8000 Hz. With that specification 48<br>
bytes means 3 ms packets, not 1 ms.<br>
<br>
> But for WBS the timing between 2 SCO packets needs to be *7.5 Milli Sec.*<br>
><br>
> *May I know how to change the packet interval between the 2 SCO packets.*<br>
<br>
The write_block_size variable in src/modules/bluetooth/module-<wbr>bluez5-<br>
device.c controls how big packets pulseaudio writes. That in turn is<br>
calculated based on write_link_mtu, and that comes from the transport<br>
acquire() callback. The ofono backend always returns 48 bytes. The<br>
native backend returns 48 bytes by default, but it can also be<br>
configured to ask the kernel what the real MTU is.<br>
<span class="HOEnZb"><font color="#888888"><br></font></span></blockquote><div>
<div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial"><br class="gmail-Apple-interchange-newline">I am able to set the MTU to 60 bytes in the and able to make the SCO connection.</div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial">But still, the data rate is maintained as 1 msec.</div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial"><br></div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial">Do we need to introduce any latency in the PA?</div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial">As per core spec<span> </span><span class="gmail-gr_ gmail-gr_250 gmail-gr-alert gmail-gr_gramm gmail-gr_inline_cards gmail-gr_disable_anim_appear gmail-Style gmail-multiReplace" id="gmail-250" style="display:inline;border-bottom:2px solid transparent;background-repeat:no-repeat;color:inherit;font-size:inherit">5 ,</span><span> </span>Vol 4 Part B of USB transaction the HCI packet interval need to be 7.5msec.</div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial">Do we need to maintain the rate in PA?</div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial"><br></div>
</div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="HOEnZb"><font color="#888888">
--<br>
Tanu<br>
<br>
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</font></span></blockquote></div><br></div></div>