痞子衡嵌入式：語音處理工具pzh-speech誕生記（4）- 音訊錄播實現(PyAudio)
阿新 • • 發佈：2020-01-30
大家好，我是痞子衡，是正經搞技術的痞子。今天痞子衡給大家介紹的是語音處理工具pzh-py-speech誕生之音訊錄播實現。
音訊錄播是pzh-py-speech的主要功能，pzh-py-speech藉助的是Python自帶wave庫以及第三方PyAudio庫來實現的音訊播放和錄製功能，今天痞子衡為大家介紹音訊錄播在pzh-py-speech中是如何實現的。
一、wave簡介
wave是python標準庫，其可以實現wav音訊檔案的讀寫，並且能解析wav音訊的引數。pzh-py-speech藉助wave庫來讀寫wav檔案，播放音訊時藉助wave庫來讀取wav檔案並獲取音訊引數（通道，取樣寬度，取樣率），錄製音訊時藉助wave庫來設定音訊引數並儲存成wav檔案。下面列舉了pzh-py-speech所用到的全部API：
- wave用法: https://docs.python.org/2/library/wave.html
wave.open() # wav音訊讀API Wave_read.getnchannels() # 獲取音訊通道數 Wave_read.getsampwidth() # 獲取音訊取樣寬度 Wave_read.getframerate() # 獲取音訊取樣率 Wave_read.getnframes() # 獲取音訊總幀數 Wave_read.readframes(n) # 讀取音訊幀資料 Wave_read.tell() # 獲取已讀取的音訊幀數 Wave_read.close() # wav音訊寫API Wave_write.setnchannels(n) # 設定音訊通道數 Wave_write.setsampwidth(n) # 設定音訊取樣寬度 Wave_write.setframerate(n) # 設定音訊取樣率 Wave_write.writeframes(data) # 寫入音訊幀資料 Wave_write.close()
二、PyAudio簡介
PyAudio是開源跨平臺音訊庫PortAudio的python封裝，PyAudio庫的維護者是Hubert Pham，該庫從2006年開始推出，一直持續更新至今，pzh-py-speech使用的是PyAudio 0.2.11。
pzh-py-speech藉助PyAudio庫來實現音訊資料流控制（包括從PC麥克風獲取音訊流，將音訊流輸出給PC揚聲器），如果說wave庫實現的是對wav檔案的單純操作，那麼PyAudio庫則實現的是音訊相關硬體裝置的互動。
PyAudio專案的官方主頁如下：
- PortAudio官方主頁: http://www.portaudio.com/
- PyAudio官方主頁: http://people.csail.mit.edu/hubert/pyaudio/
- PyAudio安裝方法: https://pypi.org/project/PyAudio/
PyAudio對音訊流的控制有兩種，一種是阻塞式的，另一種是非阻塞式的(callback)，前者一般用於確定的音訊控制（比如單純播放一個本地音訊檔案，並且中途不會有暫停/繼續等操作），後者一般用於靈活的音訊控制（比如錄製一段音訊，但是要等待一個事件響應才會結束）。pzh-py-speech用的是後者。下面是兩種方式的音訊播放使用示例：
import pyaudio
import wave
CHUNK = 1024
wf = wave.open(“test.wav”, 'rb')
p = pyaudio.PyAudio()
##########################################################
# 此為阻塞式，迴圈讀取1024個byte音訊資料去播放，直到test.wav檔案資料被全部讀出
stream = p.open(format=p.get_format_from_width(wf.getsampwidth()),
channels=wf.getnchannels(),
rate=wf.getframerate(),
output=True)
data = wf.readframes(CHUNK)
while data != '':
stream.write(data)
data = wf.readframes(CHUNK)
##########################################################
# 此為非阻塞式的(callback)，系統會自動讀取test.wav檔案裡的音訊幀，直到播放完畢
def callback(in_data, frame_count, time_info, status):
data = wf.readframes(frame_count)
return (data, pyaudio.paContinue)
stream = p.open(format=p.get_format_from_width(wf.getsampwidth()),
channels=wf.getnchannels(),
rate=wf.getframerate(),
output=True,
stream_callback=callback)
stream.start_stream()
while stream.is_active():
time.sleep(0.1)
##########################################################
stream.stop_stream()
stream.close()
p.terminate()三、pzh-py-speech音訊錄播實現
3.1 播放實現
播放功能本身實現不算複雜，但pzh-py-speech裡實現的是播放按鈕的五種狀態Start -> Play -> Pause -> Resume -> End控制，即播放中途實現了暫停和恢復，因此程式碼要稍微複雜一些。此處的重點是playAudioCallback()函式裡的else分支，如果在暫停狀態下，必須還是要給PyAudio返回一段空資料：
import wave
import pyaudio
AUDIO_PLAY_STATE_START = 0
AUDIO_PLAY_STATE_PLAY = 1
AUDIO_PLAY_STATE_PAUSE = 2
AUDIO_PLAY_STATE_RESUME = 3
AUDIO_PLAY_STATE_END = 4
class mainWin(win.speech_win):
def __init__(self, parent):
# ...
# Start -> Play -> Pause -> Resume -> End
self.playState = AUDIO_PLAY_STATE_START
def viewAudio( self, event ):
self.wavPath = self.m_genericDirCtrl_audioDir.GetFilePath()
if self.playState != AUDIO_PLAY_STATE_START:
self.playState = AUDIO_PLAY_STATE_END
self.m_button_play.SetLabel('Play Start')
def playAudioCallback(self, in_data, frame_count, time_info, status):
if self.playState == AUDIO_PLAY_STATE_PLAY or self.playState == AUDIO_PLAY_STATE_RESUME:
data = self.wavFile.readframes(frame_count)
if self.wavFile.getnframes() == self.wavFile.tell():
status = pyaudio.paComplete
self.playState = AUDIO_PLAY_STATE_END
self.m_button_play.SetLabel('Play Start')
else:
status = pyaudio.paContinue
return (data, status)
else:
# Note!!!:
data = numpy.zeros(frame_count*self.wavFile.getnchannels()).tostring()
return (data, pyaudio.paContinue)
def playAudio( self, event ):
if os.path.isfile(self.wavPath):
if self.playState == AUDIO_PLAY_STATE_END:
self.playState = AUDIO_PLAY_STATE_START
self.wavStream.stop_stream()
self.wavStream.close()
self.wavPyaudio.terminate()
self.wavFile.close()
if self.playState == AUDIO_PLAY_STATE_START:
self.playState = AUDIO_PLAY_STATE_PLAY
self.m_button_play.SetLabel('Play Pause')
self.wavFile = wave.open(self.wavPath, "rb")
self.wavPyaudio = pyaudio.PyAudio()
self.wavStream = self.wavPyaudio.open(format=self.wavPyaudio.get_format_from_width(self.wavFile.getsampwidth()),
channels=self.wavFile.getnchannels(),
rate=self.wavFile.getframerate(),
output=True,
stream_callback=self.playAudioCallback)
self.wavStream.start_stream()
elif self.playState == AUDIO_PLAY_STATE_PLAY or self.playState == AUDIO_PLAY_STATE_RESUME:
self.playState = AUDIO_PLAY_STATE_PAUSE
self.m_button_play.SetLabel('Play Resume')
elif self.playState == AUDIO_PLAY_STATE_PAUSE:
self.playState = AUDIO_PLAY_STATE_RESUME
self.m_button_play.SetLabel('Play Pause')
else:
pass3.2 錄製實現
相比播放功能，錄製功能就簡單了些，因為錄製按鈕狀態就兩種Start -> End，暫不支援中斷後繼續錄製。這裡的重點主要是音訊三大引數（取樣寬度，取樣率，通道數）設定的支援：
import wave
import pyaudio
class mainWin(win.speech_win):
def recordAudioCallback(self, in_data, frame_count, time_info, status):
if not self.isRecording:
status = pyaudio.paComplete
else:
self.wavFrames.append(in_data)
status = pyaudio.paContinue
return (in_data, status)
def recordAudio( self, event ):
if not self.isRecording:
self.isRecording = True
self.m_button_record.SetLabel('Record Stop')
# Get the wave parameter from user settings
fileName = self.m_textCtrl_recFileName.GetLineText(0)
if fileName == '':
fileName = 'rec_untitled1.wav'
self.wavPath = os.path.join(os.path.dirname(os.path.abspath(os.path.dirname(__file__))), 'conv', 'rec', fileName)
self.wavSampRate = int(self.m_choice_sampRate.GetString(self.m_choice_sampRate.GetSelection()))
channels = self.m_choice_channels.GetString(self.m_choice_channels.GetSelection())
if channels == 'Mono':
self.wavChannels = 1
else: #if channels == 'Stereo':
self.wavChannels = 2
bitDepth = int(self.m_choice_bitDepth.GetString(self.m_choice_bitDepth.GetSelection()))
if bitDepth == 8:
self.wavBitFormat = pyaudio.paInt8
elif bitDepth == 24:
self.wavBitFormat = pyaudio.paInt24
elif bitDepth == 32:
self.wavBitFormat = pyaudio.paFloat32
else:
self.wavBitFormat = pyaudio.paInt16
# Record audio according to wave parameters
self.wavFrames = []
self.wavPyaudio = pyaudio.PyAudio()
self.wavStream = self.wavPyaudio.open(format=self.wavBitFormat,
channels=self.wavChannels,
rate=self.wavSampRate,
input=True,
frames_per_buffer=AUDIO_CHUNK_SIZE,
stream_callback=self.recordAudioCallback)
self.wavStream.start_stream()
else:
self.isRecording = False
self.m_button_record.SetLabel('Record Start')
self.wavStream.stop_stream()
self.wavStream.close()
self.wavPyaudio.terminate()
# Save the wave data into file
wavFile = wave.open(self.wavPath, 'wb')
wavFile.setnchannels(self.wavChannels)
wavFile.setsampwidth(self.wavPyaudio.get_sample_size(self.wavBitFormat))
wavFile.setframerate(self.wavSampRate)
wavFile.writeframes(b''.join(self.wavFrames))
wavFile.close()至此，語音處理工具pzh-py-speech誕生之音訊錄播實現痞子衡便介紹完畢了，掌聲在哪裡~~~
參考文件
- Python解析Wav檔案並繪製波形的方法