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QAudioDeviceInfo::availableDevices(QAudio::Mode::AudioInput) returning output devices



  • I'm creating a widget to display/select audio devices. As per the post title I'm getting some output devices showing in the list of input devices. I'm on Linux Mint (Ubuntu 16.04).

    Here's a screenshot of the device tree:
    oututdevices.png

    Running a debug build in Creator I see this output while the code is probing for devices:

    ALSA lib pcm_route.c:867:(find_matching_chmap) Found no matching channel map
    ALSA lib pcm_route.c:867:(find_matching_chmap) Found no matching channel map
    ALSA lib pcm_route.c:867:(find_matching_chmap) Found no matching channel map
    ALSA lib pcm_route.c:867:(find_matching_chmap) Found no matching channel map
    ALSA lib pcm_route.c:867:(find_matching_chmap) Found no matching channel map
    ALSA lib pcm_route.c:867:(find_matching_chmap) Found no matching channel map
    ALSA lib pcm_route.c:867:(find_matching_chmap) Found no matching channel map
    ALSA lib pcm_route.c:867:(find_matching_chmap) Found no matching channel map
    ALSA lib pcm_route.c:867:(find_matching_chmap) Found no matching channel map
    ALSA lib pcm_route.c:867:(find_matching_chmap) Found no matching channel map
    ALSA lib pcm_route.c:867:(find_matching_chmap) Found no matching channel map
    ALSA lib pcm_route.c:867:(find_matching_chmap) Found no matching channel map
    ALSA lib pcm_route.c:867:(find_matching_chmap) Found no matching channel map
    ALSA lib pcm_route.c:867:(find_matching_chmap) Found no matching channel map
    ALSA lib pcm_route.c:867:(find_matching_chmap) Found no matching channel map
    ALSA lib pcm_route.c:867:(find_matching_chmap) Found no matching channel map
    ALSA lib pcm_route.c:867:(find_matching_chmap) Found no matching channel map
    ALSA lib pcm_route.c:867:(find_matching_chmap) Found no matching channel map
    ALSA lib pcm_dmix.c:968:(snd_pcm_dmix_open) The dmix plugin supports only playback stream
    ALSA lib pcm_dmix.c:968:(snd_pcm_dmix_open) The dmix plugin supports only playback stream
    ALSA lib pcm_dmix.c:968:(snd_pcm_dmix_open) The dmix plugin supports only playback stream
    ALSA lib pcm_dmix.c:968:(snd_pcm_dmix_open) The dmix plugin supports only playback stream
    ALSA lib pcm_dmix.c:968:(snd_pcm_dmix_open) The dmix plugin supports only playback stream
    ALSA lib pcm_dmix.c:968:(snd_pcm_dmix_open) The dmix plugin supports only playback stream
    ALSA lib pcm_dmix.c:1029:(snd_pcm_dmix_open) unable to open slave
    ALSA lib pcm_dmix.c:1029:(snd_pcm_dmix_open) unable to open slave
    ALSA lib pcm_dmix.c:1029:(snd_pcm_dmix_open) unable to open slave
    ALSA lib pcm_dmix.c:1029:(snd_pcm_dmix_open) unable to open slave
    ALSA lib pcm_dmix.c:1029:(snd_pcm_dmix_open) unable to open slave
    ALSA lib pcm_dmix.c:1029:(snd_pcm_dmix_open) unable to open slave
    ALSA lib pcm_dmix.c:1029:(snd_pcm_dmix_open) unable to open slave
    ALSA lib pcm_dmix.c:1029:(snd_pcm_dmix_open) unable to open slave
    ALSA lib pcm_dmix.c:1029:(snd_pcm_dmix_open) unable to open slave
    ALSA lib pcm_dmix.c:1029:(snd_pcm_dmix_open) unable to open slave
    ALSA lib pcm_dmix.c:1029:(snd_pcm_dmix_open) unable to open slave
    ALSA lib pcm_dmix.c:1029:(snd_pcm_dmix_open) unable to open slave
    ALSA lib pcm_dmix.c:1029:(snd_pcm_dmix_open) unable to open slave
    ALSA lib pcm_dmix.c:1029:(snd_pcm_dmix_open) unable to open slave
    ALSA lib pcm_dmix.c:1029:(snd_pcm_dmix_open) unable to open slave
    ALSA lib pcm_dmix.c:1029:(snd_pcm_dmix_open) unable to open slave
    ALSA lib pcm_dmix.c:1029:(snd_pcm_dmix_open) unable to open slave
    ALSA lib pcm_dmix.c:1029:(snd_pcm_dmix_open) unable to open slave
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    ALSA lib pcm_dsnoop.c:545:(snd_pcm_dsnoop_open) The dsnoop plugin supports only capture stream
    

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    @hummingway I'm not sure what your question is. Is it about these ALSA warnings?



  • Are you talking about those "alsa_output......monitor" devices? Those are not output devices.
    They are monitor sources that can use whatever comes from the output as input, something like "What-U-Hear" or "Stereo Mix" in Windows.



  • @Bonnie said in QAudioDeviceInfo::availableDevices(QAudio::Mode::AudioInput) returning output devices:

    Are you talking about those "alsa_output......monitor" devices? Those are not output devices.
    They are monitor sources that can use whatever comes from the output as input, something like "What-U-Hear" or "Stereo Mix" in Windows.

    Sorry for not being clear. That was I was wondering about. Thanks.


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