<div dir="ltr">Sorry, I didn't change the Subject. <div> Hi, Thank you for prompt reply. > Can't you use a newer version? We are at 11.1 already and the > bluetooth code has changed significantly. I hope to do so, but I am developing on a embedded system (linux kernel 3.10.49 Openwrt). And I use BlueZ 5.30. If pulseaudio 11.1 doesn't depend on kernel version, I would like to install pulseaudio 11.1. Does it any dependency on this? > When you record from the BT headset, the BT headset is set to HSP/HFP. > This means that recording and playback stream are at 8kHz, not 16kHz. > Pulseaudio only supports CVSD codec, not mSBC. Thank you, I understand what codec pulseaudio uses. So pulseaudio convert codec like this? My app <- Linear 16bit 16kHz <- Pulseaudio <- CVSD codec ( 8kHz?) <- Bluetooth Headset My application want to use a Linear 16bit 16kHz because of a DSP spec. From your point out, Do I have to set a sample format to PA_SAMPLE_U8? If so, Do I have to convert voice packet which I get from callback from 8kHz to 16kHz? I thought pulseaudio do this. And I could get a voice data by 96byte per 10ms. If stream is 8kHz, What codec could get in My app? PCM 8bit? I couldn't understand why My app get 96byte per 10ms. >resample-method=trivial might result in bad audio quality. I did set because CPU load is extremely high. I don't know why CPU load is high. So CPU load becomes low, I'll change configuration file. Best Regards, Shinnosuke Suzuki Date: Thu, 8 Feb 2018 13:24:49 +0100 > > From: Georg Chini <<a href="mailto:georg@chini.tk">georg@chini.tk</a>> > To: General PulseAudio Discussion > <<a href="mailto:pulseaudio-discuss@lists.freedesktop.org">pulseaudio-discuss@lists.freedesktop.org</a>>, Shinnosuke Suzuki > <<a href="mailto:suzukisn@gmail.com">suzukisn@gmail.com</a>> > Subject: Re: [pulseaudio-discuss] Sample format spec with Linear 16bit > 16kHz > Message-ID: <<a href="mailto:3ba83b18-c006-bf24-7f84-7ebeac5fbba5@chini.tk">3ba83b18-c006-bf24-7f84-7ebeac5fbba5@chini.tk</a>> > Content-Type: text/plain; charset=utf-8; format=flowed > > On 08.02.2018 12:06, Shinnosuke Suzuki wrote: > > Hi > > > > I am developing a phone app using pulseaudio 6.0 with asynchronous API > > using Bluetooth Headset. > > Can't you use a newer version? We are at 11.1 already and the > bluetooth code has changed significantly. > > > > > I create a record stream with pa_stream_new() with this parameter. > > static pa_sample_spec samplespec = { > > .format = PA_SAMPLE_S16LE, /* Linear 16bit */ > > .rate = 16000, /* 16000Hz */ > > .channels = 1 /* mono */ > > } > > And I set a callback function by pa_stream_set_read_callback(). > > After the stream created, I could get a voice data by 96byte per 10ms > > in this callback.I checked a log with clock_gettime() in this callback. > > > > I think I get voice packet by 320Byte per 10ms. > > 16000Hz * 1 * 16bit = 256kbps = 32KBps > > This means that I can get 320Byte per 10ms. > > So I need to get 320Byte per 10ms. > > > > I set sample format above, but I got different voice packet from callback. > > I would like to get a voice with Linear 16bit 16kHz mono. > > Is there additional configuration to this codec? > > > > For confirmation, when I use a bluetooth headset, Is this correct the > > pulseaudio convert codec from SBC to Linear as follows? > > My app <- Linear 16bit 16kHz <- Pulseaudio <- SBC codec <- Bluetooth > > Headset > > When you record from the BT headset, the BT headset is set to HSP/HFP. > This means that recording and playback stream are at 8kHz, not 16kHz. > Pulseaudio only supports CVSD codec, not mSBC. > > > > > And addition to that, After stream connected, CPU load for pulseaudio > > rose up 50%-60%.CPU load for MyAPP rose up 20%-30%. > > In order to reduce CPU load, I conigure as follows: > > high-priority = no > > realtime-scheduling = no > > resample-method=trivial > > > resample-method=trivial might result in bad audio quality.</div></div>