On 09.02.2018 07:17, Shinnosuke Suzuki wrote: > Sorry, I didn't change the Subject. > > 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? PA 11.1 should work fine with your kernel and bluez version. > > > 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. yes, PA will do the re-sampling. > 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. You should not expect to get a fixed number of bytes in a fixed time interval. This is only true on average but not for a single callback. Are the 96 bytes an average value? If your application needs constant size data packets, you may have to buffer some data. Did you take a look at the pacat code to see how reading data from a stream is done correctly? > > >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. Did you test other resample methods? There are quite a few available and "trivial" is definitely the worst of them.
