python - 每次用户按键时如何录制音频？

Question

如何不确定地录制用户的音频，当且仅当用户按下 ctrl 键并在用户按下 ctrl+c 键时关闭录制循环？到目前为止，基于一些在线示例构建了这个脚本：

from pynput import keyboard
import time, os
import pyaudio
import wave
import sched
import sys
from playsound import playsound


CHUNK = 8192
FORMAT = pyaudio.paInt16
CHANNELS = 2
RATE = 44100
WAVE_OUTPUT_FILENAME = "mic.wav"

p = pyaudio.PyAudio()
frames = []

def callback(in_data, frame_count, time_info, status):
    frames.append(in_data)
    return (in_data, pyaudio.paContinue)

class MyListener(keyboard.Listener):
    def __init__(self):
        super(MyListener, self).__init__(self.on_press, self.on_release)
        self.key_pressed = None
        self.wf = wave.open(WAVE_OUTPUT_FILENAME, 'wb')
        self.wf.setnchannels(CHANNELS)
        self.wf.setsampwidth(p.get_sample_size(FORMAT))
        self.wf.setframerate(RATE)
    def on_press(self, key):

        try:
            if key.ctrl:
                self.key_pressed = True
            return True
        except AttributeError:
            sys.exit()





    def on_release(self, key):

        if key.ctrl:
            self.key_pressed = False
        return True


listener = MyListener()


listener.start()
started = False
stream = None

def recorder():
    global started, p, stream, frames

    while True:

        try:
            if listener.key_pressed and not started:
                # Start the recording
                try:
                    stream = p.open(format=FORMAT,
                                    channels=CHANNELS,
                                    rate=RATE,
                                    input=True,
                                    frames_per_buffer=CHUNK,
                                    stream_callback = callback)
                    print("Stream active:", stream.is_active())
                    started = True
                    print("start Stream")
                except KeyboardInterrupt:
                    print('\nRecording finished: ' + repr(WAVE_OUTPUT_FILENAME))
                    quit()

            elif not listener.key_pressed and started:

                print("Stop recording")
                listener.wf.writeframes(b''.join(frames))
                listener.wf.close()
                print("You should have a wav file in the current directory")
                print('-> Playing recorded sound...')
                playsound(str(os.getcwd())+'/mic.wav')
                os.system('python "/Users/user/rec.py"')

        except KeyboardInterrupt:
            print('\nRecording finished: ' + repr(WAVE_OUTPUT_FILENAME))
            quit()
        except AttributeError:
            quit()





print ("-> Press and hold the 'ctrl' key to record your audio")
print ("-> Release the 'ctrl' key to end recording")


recorder()

问题是它确实效率低下，例如计算机开始发热。我发现让程序继续运行并录制不同音频样本的唯一方法是：os.system('python "/Users/user/rec.py"'). 为了完成程序，我尝试通过以下方式捕获异常：

except AttributeError:
       sys.exit()

或使用用户输入：

if key.ctrl_c:
   sys.exit()

基于 pyinput docs，我尝试有效地使用监听器。但是，对于这种特定情况，推荐使用这些侦听器的方式是什么？

标签： pythonpython-3.xinputpyaudio

Answer 1

至于您的计算机似乎工作非常努力的主要问题，那是因为您使用了一个while循环来不断检查何时释放记录键。在这个循环中，计算机将尽可能快地循环，而无需休息。

更好的解决方案是使用事件驱动编程，让操作系统定期通知您事件，并在事件发生时检查您是否想做任何事情。这听起来可能很复杂，但幸运pynput的是为您完成了大部分艰苦的工作。

如果您跟踪录制或播放的状态，则在下次发生控制键按下事件时开始新录制也相当简单，而无需为每个新录制递归调用整个新进程的“hack”。键盘侦听器内的事件循环将继续进行，直到其中一个回调函数返回False或引发self.stopException()。

我创建了一个简单的listener类，类似于您最初尝试调用记录器或播放器实例（稍后将介绍）来启动和停止。我也不得不同意 Anwarvic<ctl-c>应该保留作为停止脚本的紧急方式，因此我将停止命令更改为字母q。

class listener(keyboard.Listener):
    def __init__(self, recorder, player):
        super().__init__(on_press = self.on_press, on_release = self.on_release)
        self.recorder = recorder
        self.player = player
    
    def on_press(self, key):
        if key is None: #unknown event
            pass
        elif isinstance(key, keyboard.Key): #special key event
            if key.ctrl and self.player.playing == 0:
                self.recorder.start()
        elif isinstance(key, keyboard.KeyCode): #alphanumeric key event
            if key.char == 'q': #press q to quit
                if self.recorder.recording:
                    self.recorder.stop()
                return False #this is how you stop the listener thread
            if key.char == 'p' and not self.recorder.recording:
                self.player.start()
                
    def on_release(self, key):
        if key is None: #unknown event
            pass
        elif isinstance(key, keyboard.Key): #special key event
            if key.ctrl:
                self.recorder.stop()
        elif isinstance(key, keyboard.KeyCode): #alphanumeric key event
            pass

if __name__ == '__main__':
    r = recorder("mic.wav")
    p = player("mic.wav")
    l = listener(r, p)
    print('hold ctrl to record, press p to playback, press q to quit')
    l.start() #keyboard listener is a thread so we start it here
    l.join() #wait for the tread to terminate so the program doesn't instantly close

有了这个结构，我们就需要一个记录器类，它有一个启动和停止函数，它不会阻塞（异步）监听线程继续接收关键事件。PyAudio 的文档为异步输出提供了一个很好的示例，所以我只是将它应用于输入。稍作重新安排，以及让我们的听众知道我们稍后录制的标志，我们有一个记录器类：

class recorder:
    def __init__(self, 
                 wavfile, 
                 chunksize=8192, 
                 dataformat=pyaudio.paInt16, 
                 channels=2, 
                 rate=44100):
        self.filename = wavfile
        self.chunksize = chunksize
        self.dataformat = dataformat
        self.channels = channels
        self.rate = rate
        self.recording = False
        self.pa = pyaudio.PyAudio()

    def start(self):
        #we call start and stop from the keyboard listener, so we use the asynchronous 
        # version of pyaudio streaming. The keyboard listener must regain control to 
        # begin listening again for the key release.
        if not self.recording:
            self.wf = wave.open(self.filename, 'wb')
            self.wf.setnchannels(self.channels)
            self.wf.setsampwidth(self.pa.get_sample_size(self.dataformat))
            self.wf.setframerate(self.rate)
            
            def callback(in_data, frame_count, time_info, status):
                #file write should be able to keep up with audio data stream (about 1378 Kbps)
                self.wf.writeframes(in_data) 
                return (in_data, pyaudio.paContinue)
            
            self.stream = self.pa.open(format = self.dataformat,
                                       channels = self.channels,
                                       rate = self.rate,
                                       input = True,
                                       stream_callback = callback)
            self.stream.start_stream()
            self.recording = True
            print('recording started')
    
    def stop(self):
        if self.recording:         
            self.stream.stop_stream()
            self.stream.close()
            self.wf.close()
            
            self.recording = False
            print('recording finished')

最后，我们创建一个音频播放器，用于在您按下 时播放音频p。我将 PyAudio 示例放入每次按下按钮时创建的线程中，以便可以创建多个相互重叠的播放器。我们还跟踪有多少玩家正在播放，因此我们不会在文件已被玩家使用时尝试记录。（我还在顶部包含了我的导入）

from threading import Thread, Lock
from pynput import keyboard
import pyaudio
import wave

class player:
    def __init__(self, wavfile):
        self.wavfile = wavfile
        self.playing = 0 #flag so we don't try to record while the wav file is in use
        self.lock = Lock() #muutex so incrementing and decrementing self.playing is safe
    
    #contents of the run function are processed in another thread so we use the blocking
    # version of pyaudio play file example: http://people.csail.mit.edu/hubert/pyaudio/#play-wave-example
    def run(self):
        with self.lock:
            self.playing += 1
        with wave.open(self.wavfile, 'rb') as wf:
            p = pyaudio.PyAudio()
            stream = p.open(format=p.get_format_from_width(wf.getsampwidth()),
                            channels=wf.getnchannels(),
                            rate=wf.getframerate(),
                            output=True)
            data = wf.readframes(8192)
            while data != b'':
                stream.write(data)
                data = wf.readframes(8192)

            stream.stop_stream()
            stream.close()
            p.terminate()
            wf.close()
        with self.lock:
            self.playing -= 1
        
    def start(self):
        Thread(target=self.run).start()

我不能保证这完全没有错误，但如果您对它的工作原理/如何使其工作有任何疑问，请随时发表评论。