[pjsip] Audio distortion in Linux

[Thomas Kluge]

We have a strange audio distortion using fileinput or the portaudio
interface in pjsip under linux with the current version and different linux
distribiutions but not in Win32. I would describe the distortion as humming
bass.

I followed the suggestions in the audio troubleshooter section in pjsip wiki
(http://trac.pjsip.org/repos/wiki/sound-problems) but nothing helped.


The distortion depends on the input audio signal level and frequency and is
caused by the encoding side.

The following audio samples shall demonstrate this:

The original source 44.1 KHz 16 bit mono:
www.bercos.de/public/testsounds/test_audio_441_16_cut-mono.wav

Local loop with pjsua in Win32 with G.722
www.bercos.de/public/testsounds/rec_local-PC-16-44100-G722.wav

Audio encoded on Linux and played in Win32 with G.722 (with distortion)
www.bercos.de/public/testsounds/rec_Linux-PC-16-44100-G722.wav

Same as before but encoded with L16/44100 (no difference, with distortion)
www.bercos.de/public/testsounds/rec_Linux-PC-16-44100-L16_441000.wav

Same  as before but input over Alsa-Jack->PortAudio->pjsua on Linux (with
distortion)
www.bercos.de/public/testsounds/rec_Linux-PC-linein_Jack-PortAudio-G722.wav

Now back to Alsa input in pjsua on Linux (please ignore drop-outs, sound is
clear)
www.bercos.de/public/testsounds/rec_Linux-PC-Micro-44100-G722.wav


Used command line options (have no influence on the problem):
    --ec-tail=0
    --no-vad
    --quality=6

user.mak settings
    export CFLAGS += -DPA_USE_JACK=1 -DPA_USE_ALSA=1 -DPA_USE_OSS=1
    export LDFLAGS += -ljack
    export PORTAUDIO_OBJS += pa_jack.o pa_ringbuffer.o

config_site.h settings
    #define PJMEDIA_HAS_GSM_CODEC 0
    #define PJMEDIA_HAS_L16_CODEC 1
    #define PJMEDIA_HAS_ILBC_CODEC 0
    #define PJMEDIA_HAS_SPEEX_CODEC 1
    #define PJMEDIA_HAS_G722_CODEC 1

    #define PJMEDIA_HAS_SRTP 1


Does anybody have an idea what the reason might be?


Another problem:
    If define PJMEDIA_HAS_SRTP  is enabled (default), pjsua crashes in
function pjmedia_transport_srtp_create() line 279 of endpoint.c
(Nullpointer: endpt is NULL)
    return pj_pool_create(endpt->pf, name, initial, increment, NULL);
   (only in Win32 Release Version)


best wishes,
Thomas Kluge