Hide ALSA error output

[chrisspen]

Every creation of Microphone() or listen() seems to generate the output:

ALSA lib pcm_dsnoop.c:606:(snd_pcm_dsnoop_open) unable to open slave
ALSA lib pcm_dmix.c:1029:(snd_pcm_dmix_open) unable to open slave
ALSA lib pcm.c:2266:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear
ALSA lib pcm.c:2266:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe
ALSA lib pcm.c:2266:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side
ALSA lib pcm_dmix.c:1029:(snd_pcm_dmix_open) unable to open slave

which clutter my output and makes it difficult to read other output. Otherwise, the recognition code works flawlessly. I've tried swapping out sys.stdout and sys.stderr, but this is still output, implying it's happening from a system call. Is there an easy way to suppress these errors?

[Uberi]

Hi @chrisspen,

You can use the technique described in this StackOverflow answer to do what you want:

with noalsaerr() as n, Microphone() as source:
    ...

I wouldn't recommend using this (it would be better to make the ALSA configuration correct instead), but in a pinch, this should work fine.

[chrisspen]

I also found removing the cards.pcm.* from my alsa.conf fixed some of the errors, and then explicitly entering the device_index for my microphone fixed the others. However, it's good to know about that context manager. Thanks.

[Trickery710]

import sounddevice

if you have to install it
pip3 install sounddevice

[Muszo]

import sounddevice

if you have to install it pip3 install sounddevice

Wow, that helped.
Can you please explain why importing a lib fixed the messages?

[OpenAyEye]

import sounddevice

if you have to install it pip3 install sounddevice

this is the answer. I don't know why, but it's the answer.
raspi 4 8gb bookworm raspbian

was getting alsa errors, jack errors, all sorts of errors,
i added
import sounddevice

all errors gone. if you're struggling on the raspi this is the answer.

[blokpardi]

import sounddevice solved it for me as well. Thanks @Trickery710!

[Speeder9743]

Wow @Trickery710, how does importing a lib fix all these stupid errors on the raspi?!

[Speeder9743]

import sounddevice
if you have to install it pip3 install sounddevice

this is the answer. I don't know why, but it's the answer. raspi 4 8gb bookworm raspbian

was getting alsa errors, jack errors, all sorts of errors, i added import sounddevice

all errors gone. if you're struggling on the raspi this is the answer.

Using the exact same os and pi board, @OpenAyEye !

[lstuma]

Wow @Trickery710, how does importing a lib fix all these stupid errors on the raspi?!

anybody found an answer, I'd be very interested

[renatocava]

I installed and imported the sounddevice library and the same output messages also stopped appearing. Just clarify that it is not an error, just messages that worry.