Difference between revisions of "Audio Input and Output from USB Microphone + Raspberry Pi"

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'''Introduction''':
+
== Overview ==
One of the major components of my project, Vybz, was being able to read raw audio input from a USB microphone. Information from a microphone is originally converted from an analog signal into a group of  bytes (binary digits) using the microphone’s built in A/D converter. However, bytes were a relatively difficult unit to work with. For the project, I needed access to nice integer values that were an accurate representation of the volume level in the room. Thus, this tutorial will show you how to read audio input from a USB microphone on the Raspberry Pi.
+
This tutorial will describe how to input audio to a Raspberry Pi using a USB microphone and furthermore how to output that audio simultaneously if needed.  
 +
<br/>
 +
== Materials and Prerequisites ==
 +
*USB Microphone
 +
*Raspberry Pi
 +
*Speaker for audio output
  
''Note'': The basis of the code was derived from the code developed by markjay4k, an engineer working with audio spectrum analyzers. You can find a link to his github at: https://github.com/markjay4k/Audio-Spectrum-Analyzer-in-Python
+
== Process ==
 +
'''Libraries to Install'''
 +
<br/>
 +
PyAudio: Used to play and record audio on a variety of platforms. Install it by typing
 +
<font face="Courier"><code>pip install pyaudio</code></font> into the terminal
 +
<br/>
 +
Numpy: fundamental package for scientific computing in Python. Install it by typing
 +
<font face="Courier"><code>pip install numpy</code></font> into the terminal
 +
<br/>
  
'''Step 1''': Install Libraries
+
'''Code''' <br/>
In order to read raw audio data, you will first need to install some useful libraries that will be implemented in your code. First, install pyaudio. With PyAudio, you can easily use Python to play and record audio on a variety of platforms. To install, type the following into the terminal:
+
Copy the following Python script to read audio input to wave files:
 +
<source lang="python">
 +
import pyaudio
 +
import wave
 +
import os
 +
 
 +
#The following code comes from markjay4k as referenced below
 +
form_1 = pyaudio.paInt16
 +
chans=1
 +
samp_rate = 44100
 +
chunk = 4096
 +
record_secs = 1    #record time
 +
dev_index = 2
 +
wav_output_filename = 'test1.wav'
  
<blockquote>
 
pip install pyaudio
 
</blockquote>
 
  
Then you’ll want to install NumPy which is a fundamental package for scientific computing in Python. You can install it my typing this into the terminal:
+
audio = pyaudio.PyAudio()
  
<blockquote>
+
#setup audio input stream
pip install numpy
+
stream=audio.open(format = form_1,rate=samp_rate,channels=chans, input_device_index = dev_index, input=True, frames_per_buffer=chunk)
</blockquote>
+
print("recording")
 +
frames=[]
  
'''Step 2''': The Code
+
for ii in range(0,int((samp_rate/chunk)*record_secs)):
Copy the code into your python script.
+
    data=stream.read(chunk,exception_on_overflow = False)
 +
    frames.append(data)
 +
 
 +
print("finished recording")
 +
 
 +
stream.stop_stream()
 +
stream.close()
 +
audio.terminate()
 +
 
 +
#creates wave file with audio read in
 +
#Code is from the wave file audio tutorial as referenced below
 +
wavefile=wave.open(wav_output_filename,'wb')
 +
wavefile.setnchannels(chans)
 +
wavefile.setsampwidth(audio.get_sample_size(form_1))
 +
wavefile.setframerate(samp_rate)
 +
wavefile.writeframes(b''.join(frames))
 +
wavefile.close()
 +
 
 +
#plays the audio file
 +
os.system("aplay test1.wav")
 +
 
 +
</source>
 +
Copy the following Python script for simultaneously streaming audio output with input:
  
 
<source lang="python">
 
<source lang="python">
 
import pyaudio
 
import pyaudio
import struct
 
 
import numpy as np
 
import numpy as np
  
+
#The following code comes from markjay4k as referenced below
CHUNK = 1024 * 4        # samples per frame
+
 
FORMAT = pyaudio.paInt16 # audio format (bytes per sample)
+
chunk=4096
CHANNELS = 1              # single channel for microphone
+
RATE=44100
RATE = 44100                # samples per second
+
 
 +
p=pyaudio.PyAudio()
  
+
#input stream setup
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stream=p.open(format = pyaudio.paInt16,rate=RATE,channels=1, input_device_index = 2, input=True, frames_per_buffer=chunk)
p = pyaudio.PyAudio()
 
 
stream = p.open(
 
    format=FORMAT,
 
    channels=CHANNELS,
 
    rate=RATE,
 
    input=True,
 
    output=True,
 
    frames_per_buffer=CHUNK
 
)
 
  
while True:
+
#the code below is from the pyAudio library documentation referenced below
    data = stream.read(CHUNK)                 #reading input
+
#output stream setup
    data_int = struct.unpack(str(2 * CHUNK) + 'B', data) #converts bytes to integers
+
player=p.open(format = pyaudio.paInt16,rate=RATE,channels=1, output=True, frames_per_buffer=chunk)
    data_int                               #prints the integer values
 
  
 +
while True:            #Used to continuously stream audio
 +
    data=np.fromstring(stream.read(chunk,exception_on_overflow = False),dtype=np.int16)
 +
    player.write(data,chunk)
 +
   
 +
#closes streams
 +
stream.stop_stream()
 +
stream.close()
 +
p.terminate
 
</source>
 
</source>
'''Step 3''':  
+
 
Run the code. Once you run the code, you should be able to see the running integer values for the bytes taken in by your microphone.
+
== Authors ==
 +
Pavan Narahari - Fall 2018 <br/>
 +
Sam Manyak - Fall 2018
 +
<br/>
 +
== Group Link ==
 +
[https://classes.engineering.wustl.edu/ese205/core/index.php?title=Crutooth Crutooth]
 +
<br/>
 +
== References ==
 +
*The basis of the code was derived from the code developed by markjay4k, an engineer working with audio spectrum analyzers. You can find a link to his github at: https://github.com/markjay4k/Audio-Spectrum-Analyzer-in-Python
 +
*Here is the documentation for the PyAudio Library: [https://people.csail.mit.edu/hubert/pyaudio/docs/ PyAudio]
 +
*Tutorial for audio input to wave file: https://docs.python.org/3/library/wave.html
 +
 
  
 
[[Category:HowTos]]
 
[[Category:HowTos]]
 +
[[Category:Programming]]
 +
[[Category:Raspberry_Pi]]

Latest revision as of 16:23, 11 December 2018

Overview

This tutorial will describe how to input audio to a Raspberry Pi using a USB microphone and furthermore how to output that audio simultaneously if needed.

Materials and Prerequisites

  • USB Microphone
  • Raspberry Pi
  • Speaker for audio output

Process

Libraries to Install
PyAudio: Used to play and record audio on a variety of platforms. Install it by typing pip install pyaudio into the terminal
Numpy: fundamental package for scientific computing in Python. Install it by typing pip install numpy into the terminal

Code
Copy the following Python script to read audio input to wave files:

import pyaudio
import wave
import os

#The following code comes from markjay4k as referenced below
form_1 = pyaudio.paInt16
chans=1
samp_rate = 44100
chunk = 4096
record_secs = 1     #record time
dev_index = 2
wav_output_filename = 'test1.wav'


audio = pyaudio.PyAudio()

#setup audio input stream
stream=audio.open(format = form_1,rate=samp_rate,channels=chans, input_device_index = dev_index, input=True, frames_per_buffer=chunk)
print("recording")
frames=[]

for ii in range(0,int((samp_rate/chunk)*record_secs)):
    data=stream.read(chunk,exception_on_overflow = False)
    frames.append(data)

print("finished recording")

stream.stop_stream()
stream.close()
audio.terminate()

#creates wave file with audio read in
#Code is from the wave file audio tutorial as referenced below
wavefile=wave.open(wav_output_filename,'wb')
wavefile.setnchannels(chans)
wavefile.setsampwidth(audio.get_sample_size(form_1))
wavefile.setframerate(samp_rate)
wavefile.writeframes(b''.join(frames))
wavefile.close()

#plays the audio file
os.system("aplay test1.wav")

Copy the following Python script for simultaneously streaming audio output with input:

import pyaudio
import numpy as np

#The following code comes from markjay4k as referenced below

chunk=4096
RATE=44100

p=pyaudio.PyAudio()

#input stream setup
stream=p.open(format = pyaudio.paInt16,rate=RATE,channels=1, input_device_index = 2, input=True, frames_per_buffer=chunk)

#the code below is from the pyAudio library documentation referenced below
#output stream setup
player=p.open(format = pyaudio.paInt16,rate=RATE,channels=1, output=True, frames_per_buffer=chunk)

while True:            #Used to continuously stream audio
     data=np.fromstring(stream.read(chunk,exception_on_overflow = False),dtype=np.int16)
     player.write(data,chunk)
    
#closes streams
stream.stop_stream()
stream.close()
p.terminate

Authors

Pavan Narahari - Fall 2018
Sam Manyak - Fall 2018

Group Link

Crutooth

References