How to troubleshoot webcam on NetBSD

netbsdnoob

Hello all,

I wanted to understand if my webcam was working under NetBSD.
I am on a Thinkpad 450s.
Few info on my systems here.
The output of uname -a is:

NetBSD T450s 9.3 NetBSD 9.3 (GENERIC) #0: Thu Aug  4 15:30:37 UTC 2022  mkrepro@mkrepro.NetBSD.org:/usr/src/sys/arch/amd64/compile/GENERIC amd64

The output of dmesg is here: https://bpa.st/LBVQ

If I do ls /dev/video* I see four devices:

crw-rw-rw-  1 root  wheel  193, 0 Sep  9 02:09 /dev/video0
crw-rw-rw-  1 root  wheel  193, 1 Sep  9 02:09 /dev/video1
crw-rw-rw-  1 root  wheel  193, 2 Sep  9 02:09 /dev/video2
crw-rw-rw-  1 root  wheel  193, 3 Sep  9 02:09 /dev/video3

I even tried this:

mplayer tv:// -tv driver=v4l2:device=/dev/video0 -fps 30 -vo x11

with all 4 devices (video0,1,2,3) and the only one actually opening a screen is video0, but it just opens a green window and that's all.

The messages shown for video0 are here https://bpa.st/2OOQ.

NOTE: Nothing changes if I remove the -vo x11 option, I just have a bigger green box.

Any idea?

rvp

netbsdnoob Try:

mpv --no-really-quiet --profile=low-latency --untimed av://v4l2:/dev/video0

or:

ffplay4 -f v4l2 -pixel_format yuyv422 /dev/video0

after installing ffplay

netbsdnoob

rvp

rvp ok the first command gives this as output:

[ffmpeg/demuxer] video4linux2,v4l2: ioctl(VIDIOC_G_PARM): Invalid argument
[ffmpeg/demuxer] video4linux2,v4l2: Time per frame unknown
[ffmpeg/demuxer] video4linux2,v4l2: ioctl(VIDIOC_STREAMON): Input/output error
[lavf] avformat_open_input() failed
Failed to recognize file format.

I also tried it with doas/sudo but nothing changed.

The second command gave me this:https://bpa.st/NTAA

Any idea?

rvp

netbsdnoob Tried with 2 webcams (one built into the laptop, the other a cheap external USB). On 9.3, the internal one works; the external one produces the same errors and doesn't work. On -HEAD, both work.

nia

Need a CURRENT kernel most likely.

netbsdnoob

nia I just did this:

    $ su
    # cd /root
    # tar -zxpf ~/kern-GENERIC.tgz
    # ln -fh /netbsd /netbsd.old
    # cp netbsd /netbsd.new
    # ln -fh /netbsd.new /netbsd

as recommended with a downloaded kernel.
Everything works now!! Thanks a lot!

Since i never downloaded another kernel the question is... Do i also need to extract the sets? and modules?

netbsdnoob

nia now the webcam works but audio doesn't. :(

mixerctl -a gives this:

outputs.master=128,128
outputs.master.mute=off
outputs.dacsel=DP00

This looks like the wrong audio device.
Does sound work with other programs? If not, audiocfg list please.

netbsdnoob

pin Yeah! You were right!

I did audiocfg list and found out that it was set to some kind of other audio source.
So I switched to the other one with audiocfg default 1.

Will it be default?

Anyway what about mic? How can I troubleshoot it? It also doesn't seem to work.
My audiocfg list is this one anyway:

1: [*] audio1 @ hdafg1: Realtek ALC292
       playback: 2ch, 48000Hz
       record:   2ch, 48000Hz
       (PR) slinear_le 16/16, 2ch, { 32000, 44100, 48000, 88200, 96000, 192000 }
       (PR) slinear_le 20/32, 2ch, { 32000, 44100, 48000, 88200, 96000, 192000 }
       (PR) slinear_le 24/32, 2ch, { 32000, 44100, 48000, 88200, 96000, 192000 }
       (  ) ac3 16/16, 2ch, { 32000, 44100, 48000, 88200, 96000, 192000 }

Ideas for the mic?

nia

yea that looks like the audio device for the video card

netbsdnoob Will it be default?

Yes, until you update the kernel again. Just remember to switch it when you get a new kernel.

netbsdnoob Ideas for the mic?

Nope, sorry.

nia

For the microphone play with the ADC settings and unmute everything in anomixer.

netbsdnoob

nia ok yes now everything works.
I still would like to understand how the audio infrastructure works in NetBSD.
I mean in GNU/Linux there is ALSA which is the sound architecture and pulseaudio which some sort of audioserver to achieve multiplexing right? What about netbsd? I mean sometmies i see packages called alsa or stuff like that.

In addition... why does arecord -l says that there are no sound cards. Is there something wrong?

nia

netbsdnoob In netbsd the sound architecture and the mixer (what you usually need a sound server for) are the same thing, and exist in the same place (the kernel). Both are called sun audio, audio(4), audioio, NetBSD audio, or a million other names.

ALSA is available as a compatibility layer, you need to configure it with a configuration file - there is an example of how to do this somewhere on the NetBSD website. arecord is written only for ALSA so you need to configure ALSA first, before you can use it. By the way, pkgsrc supports Linux as well, so that's why there are so many ALSA-related packages...

NetBSD has its own audio recording tool called audiorecord(1), it's in the base system.