python pyaudio使用多處理

Question

我正在嘗試從音頻流中獲取樣本並將它們放入共享隊列中。 我有另一個從這個隊列中拉出來的進程。

當我跑，我得到這個錯誤：

* recording
Traceback (most recent call last):
  File "record.py", line 43, in <module>
    data = stream.read(CHUNK)
  File "/Library/Python/2.7/site-packages/pyaudio.py", line 605, in read
    return pa.read_stream(self._stream, num_frames)
IOError: [Errno Input overflowed] -9981

編輯：顯然問題已經存在一段時間沒有發布解決方案（我嘗試了他們的建議）：

• PyAudio輸入溢出-9981 - 沒有解決方案正常工作

• 在設置PyAudio Stream輸入和輸出為True時，獲取IOError：[Errno輸入溢出] -9981

• https://github.com/jeysonmc/python-google-speech-scripts/issues/1

這是（簡化）代碼：

import pyaudio
import wave
import array
import time
from multiprocessing import Queue, Process

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

p = pyaudio.PyAudio()
left = Queue()
right = Queue()

def other(q1, q2):
    while True: 
        try:
                a = q1.get(False)
        except Exception:
            pass

        try:
                b = q2.get(False)
        except Exception:
            pass

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

print("* recording")
Process(target=other, args=(left, right)).start()

for i in range(0, int(RATE / CHUNK * RECORD_SECONDS)):
    data = stream.read(CHUNK)
    byte_string = ''.join(data)
    nums = array.array('h', byte_string)
    for elt in nums[1::2]:
        left.put(elt)
    for elt in nums[0::2]:
        right.put(elt)

print("* done recording")

stream.stop_stream()
stream.close()
print "terminated"

我究竟做錯了什么？ 我在Mac OSX和Python 2.7上，我通過homebrew安裝了portaudio並嘗試了`pyaudio的pip和dmg安裝，但沒有運氣。

Answer 1

緩沖區溢出錯誤是因為您的frames_per_buffer和讀取chunksize可能太小。 嘗試更大的值，即512,2048,4096,8192等

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

for CHUNK1 in [512,2048,4096,8192,16384]:
    for CHUNK2 in [512,2048,4096,8192,16384]:
        stream = p.open(format=FORMAT,
                        channels=CHANNELS,
                        rate=RATE,
                        input=True,
                        frames_per_buffer=CHUNK1)


        try:
            print CHUNK1,CHUNK2
            for i in range(0, int(RATE / CHUNK * RECORD_SECONDS)):
                data = stream.read(CHUNK2)
        except:
            print "Boohoo"

        stream.stop_stream()
        stream.close()

---

更新

好吧，我想我明白了。 如果你在下一次讀取之前等待太久，pyaudio庫將引發溢出錯誤。

byte_string = ''.join(data)
nums = array.array('h', byte_string)
for elt in nums[1::2]:
    left.put(elt)
for elt in nums[0::2]:
    right.put(elt)

這在這里做了很多很慢的處理。 特別是在python中的兩個for循環。 讓處理過程得到一大塊單流數據，它可以處理，而不是一次一個int。

import numpy as np

...

n=np.fromstring(data,np.uint16)
left.put(n[1::2])
right.put(n[0::2])

我甚至不想想for循環對延遲的影響，但即使使用array和np.array之間相對較小的性能提升值得注意：

a=array.array('h',s)
n=np.array(a)

In [26]: %timeit n[1::2]
1000000 loops, best of 3: 669 ns per loop

In [27]: %timeit n[1::2].copy()
1000 loops, best of 3: 725 us per loop

In [28]: %timeit a[1::2]
1000 loops, best of 3: 1.91 ms per loop