Real time sound level through usb audio card?

Question

I am wondering if there is an easy way to measure the amplitude/sound level of an audio signal being input to the rasbperry pi via usb sound card. I would like to play music into the sound card input and have a python script print the sound level in real time. I have looked around at other posts involving pyaudio and scipy.io.wavefile.read, but I am still unsure. Any help is appreciated.

Answer 1

You may want to use pyaudio library.

import pyaudio
import audioop

CHUNK = 1024
FORMAT = pyaudio.paInt16
CHANNELS = 2
RATE = 44100
RECORD_SECONDS = 60

p = pyaudio.PyAudio()

stream = p.open(format=FORMAT,
                channels=CHANNELS,
                rate=RATE,
                input=True,
                frames_per_buffer=CHUNK)


for i in range(0, int(RATE / CHUNK * RECORD_SECONDS)):
    data = stream.read(CHUNK, 
                       exception_on_overflow=False)
    rms = audioop.rms(data, 2)   
    print(rms)

stream.stop_stream()
stream.close()
p.terminate()

Answer 2

Start here

http://www.techmind.org/audio/specanaly.html

I am sure there are others.