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I have a small selection of code:

stream = pyaudio.PyAudio().open(
    format   = pyaudio.PyAudio().get_format_from_width(1),
    channels = 1, 
    rate     = bitrate, 
    output   = True
)

When I run it, it produces a few lines of console output:

ALSA lib pcm_dsnoop.c:614:(snd_pcm_dsnoop_open) unable to open slave
ALSA lib pcm_dmix.c:1024:(snd_pcm_dmix_open) unable to open slave
ALSA lib pcm.c:2267:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear
ALSA lib pcm.c:2267:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe
ALSA lib pcm.c:2267:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side
ALSA lib pcm_dmix.c:1024:(snd_pcm_dmix_open) unable to open slave
Cannot connect to server socket err = No such file or directory
Cannot connect to server request channel
jack server is not running or cannot be started

How can I change my code surrounding this particular function call to make console output of the form above not appear while not making the console output of other code vanish?

I'm imagining a solution to this in the form of a context manager, perhaps something a little like the following:

@contextlib.contextmanager
def silence():
    # <insert magic to direct stdout and stderr to null>
    yield
    # <insert magic to direct stdout and stderr to console>

with silence():
    stream = pyaudio.PyAudio().open(
        format   = pyaudio.PyAudio().get_format_from_width(1),
        channels = 1, 
        rate     = bitrate, 
        output   = True
    )
d3pd
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1 Answers1

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Decorators may work. Maybe something like that:

def silence(func):
    def silenced():
        // silence output
        func()
        // change output to normal
    return silenced


@silence
def openStream(args):
    stream = pyaudio.PyAudio().open(
        format   = pyaudio.PyAudio().get_format_from_width(1),
        channels = 1, 
        rate     = bitrate, 
        output   = True
    )
    return stream
alpert
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  • Hey, thanks for the post. I was more asking about how to code the actual silencing and unsilencing things (in your code represented as comments). – d3pd Apr 30 '16 at 08:47
  • Oh, that is actually in the link above – alpert Apr 30 '16 at 10:57