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tilly

Member

Registered: 2014-01-22

Posts: 1

Audio devices list in qt-4 vs qt-5

Hello,

I'm facing two very different behaviors about audio, when using the last qt-4 vs qt-5 versions, from the official repositories, to link this simple Voip application against.

* qt4: When querying for input/output devices I get this list of devices:

* qt5: When querying for input/output devices I got this list

In both cases I started pulseaudio with -D option.
(If a shutdown pulseaudio the qt-5 device list remains the same, but the two alsa_input, alsa_output devices are not present, resulting in the problem I explain below).

Here is some usefull outputs:

$ aplay -L
--------------------------------------------------------------------------------
null
    Discard all samples (playback) or generate zero samples (capture)
pulse
    PulseAudio Sound Server
default
    Default ALSA Output (currently PulseAudio Sound Server)
sysdefault:CARD=I82801DBICH4
    Intel 82801DB-ICH4, Intel 82801DB-ICH4
    Default Audio Device
front:CARD=I82801DBICH4,DEV=0
    Intel 82801DB-ICH4, Intel 82801DB-ICH4
    Front speakers
surround21:CARD=I82801DBICH4,DEV=0
    Intel 82801DB-ICH4, Intel 82801DB-ICH4
    2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=I82801DBICH4,DEV=0
    Intel 82801DB-ICH4, Intel 82801DB-ICH4
    4.0 Surround output to Front and Rear speakers
surround41:CARD=I82801DBICH4,DEV=0
    Intel 82801DB-ICH4, Intel 82801DB-ICH4
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=I82801DBICH4,DEV=0
    Intel 82801DB-ICH4, Intel 82801DB-ICH4
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=I82801DBICH4,DEV=0
    Intel 82801DB-ICH4, Intel 82801DB-ICH4
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
iec958:CARD=I82801DBICH4,DEV=0
    Intel 82801DB-ICH4, Intel 82801DB-ICH4 - IEC958
    IEC958 (S/PDIF) Digital Audio Output

$ lsmod | grep '^snd' | column -t
--------------------------------------------------------------------------------
snd_intel8x0    34617  3
snd_intel8x0m   17500  0
snd_ac97_codec  96144  2   snd_intel8x0,snd_intel8x0m
snd_pcm         78142  3   snd_ac97_codec,snd_intel8x0,snd_intel8x0m
snd_timer       26106  1   snd_pcm
snd             55101  11  snd_ac97_codec,snd_intel8x0,snd_timer,snd_pcm,snd_intel8x0m

$ ls -l /dev/snd
--------------------------------------------------------------------------------
total 0
drwxr-xr-x  2 root root       80 Apr 18 04:48 by-path
crw-rw----+ 1 root audio 116,  5 Apr 18 04:48 controlC0
crw-rw----+ 1 root audio 116,  2 Apr 18 04:48 controlC1
crw-rw----+ 1 root audio 116,  7 Apr 18 17:25 pcmC0D0c
crw-rw----+ 1 root audio 116,  6 Apr 18 17:25 pcmC0D0p
crw-rw----+ 1 root audio 116,  8 Apr 18 04:48 pcmC0D1c
crw-rw----+ 1 root audio 116,  9 Apr 18 04:48 pcmC0D2c
crw-rw----+ 1 root audio 116, 10 Apr 18 04:48 pcmC0D3c
crw-rw----+ 1 root audio 116, 11 Apr 18 04:58 pcmC0D4p
crw-rw----+ 1 root audio 116,  4 Apr 18 04:48 pcmC1D0c
crw-rw----+ 1 root audio 116,  3 Apr 18 04:48 pcmC1D0p
crw-rw----+ 1 root audio 116,  1 Apr 18 04:48 seq
crw-rw----+ 1 root audio 116, 33 Apr 18 04:48 timer

I only uncommented the "autospawn = no" line in pulse/client.conf, leaving the rest of the "/etc/asound.conf" and "/etc/pulse/*.conf" files unchanged from the pacman repository.

Audio is working in both cases, but the only way to get the application working is to select the two distinct alsa_input and alsa_output devices hightlighted in the qt5 screenshot, otherwise after a few user interactions, the app crashes with SIGSEGV, as I reported in this post in the Qt forum.

As I mentioned there I've also tried to rebuild qt 4.8.6 against pulse audio to see if I get the same devices list, but the lists remain still the same shown in the two first qt-4 pics above.

Thanks in advance for any help.

Last edited by tilly (2015-04-18 16:37:34)