CODEWITHSUNDEEP
pythonplaybackpyaudio
bluesky
bluesky

Reputation: 255

How to get data of channel in PyAudio

I want to get data of left and right channels from sound data in PyAudio. I have 1D shape array and don't know which of them are from channels

I tried to change the first half of data to zero. I have silence. I tried to change each second number to zero. I have silence. In documentation I saw that PyAudio has a parameter "output_channels". I think it has more than one output channel.

import pyaudio
import numpy as np
CHUNK = 102
WIDTH = 2
#CHUNK = 10404
#RATE = 192000
CHANNELS = 2
RATE = 44100
p = pyaudio.PyAudio()
stream = p.open(format=p.get_format_from_width(WIDTH),
            channels=CHANNELS,
            rate=RATE,
            input=True,
            output=True,
            frames_per_buffer=CHUNK)
frames_per_buffer = 44100
data=[]
n=0
a=np.zeros(CHUNK*CHANNELS*WIDTH)
for i in range(1000):
    data.append(stream.read(CHUNK))
    for m in range(CHUNK):
        a[m]=data[0][m]
    s_0=[]
    for m in range(int(CHUNK*CHANNELS*WIDTH)):
        s_0.append(int(data[0][m]))
    a=np.asarray(s_0)
    a=a.reshape(int(CHUNK*WIDTH), 2)
    a_T = np.transpose(a)
    a_T[1][:] = 0
    a = np.transpose(a_T)
    a = a.reshape(CHUNK*CHANNELS*WIDTH)
    s_2=[]
    for m in range(CHUNK*CHANNELS*WIDTH):
        s_2.append(int(a[m]))
    sound=[bytes(s_2)]
    stream.write(sound.pop(0), CHUNK)
    data=[]
print('s_0')
s_0[0:20]
print('s_2')
s_2[0:20]

Sound doesn't play if I change data

Upvotes: 2

Views: 2583

Answers (1)

jeremy_rutman
jeremy_rutman

Reputation: 5700

This works to get channel0 from a stereo file:

import pyaudio
import wave
import numpy as np
chunk = 1024

# open up a wave
wf = wave.open('/home/jeremy/Music/440.wav', 'rb')
swidth = wf.getsampwidth()
RATE = wf.getframerate()    
# open stream
p = pyaudio.PyAudio()
channels = wf.getnchannels()
stream = p.open(format =
                p.get_format_from_width(wf.getsampwidth()),
                channels = channels,
                rate = RATE,
                output = True)
# read some data
data = wf.readframes(chunk)
while len(data) == chunk*swidth*channels:
    # write data out to the audio stream
    stream.write(data)
    indata = np.fromstring(data, dtype='int16')
    # deinterleave, select 1 channel
    channel0 = indata[0::channels]
    data = wf.readframes(chunk)
if data:
    stream.write(data)
stream.close()
p.terminate()

Upvotes: 2

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