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Jays-PySPEECH誕生之音訊顯示實現。
音訊顯示是Jays-PySPEECH的主要功能,Jays-PySPEECH藉助的是Matplotlib以及NumPy來實現的音訊顯示功能,今天痞子衡為大家介紹音訊顯示在Jays-PySPEECH中是如何實現的。
一、SciPy工具集
SciPy是一套Python科學計算相關的工具集,其本身也是一個Python庫,這個工具集主要包含以下6大Python庫,Jays-PySPEECH所用到的Matplotlib以及NumPy均屬於SciPy工具集。
1.1 NumPy
NumPy是一套最基礎的Python科學計算包,它主要用於陣列與矩陣運算,它是一個開源專案,被收錄進 NumFOCUS 組織維護的 Sponsored Project 裡。Jays-PySPEECH使用的是NumPy 1.15.0。
NumPy庫的官方主頁如下:
- NumPy官方主頁: http://www.numpy.org/
- NumPy安裝方法: https://pypi.org/project/numpy/
NumPy的快速上手可參考這個網頁 https://docs.scipy.org/doc/numpy/user/quickstart.html
1.2 Matplotlib
Matplotlib是一套Python高質量2D繪相簿,它的初始設計者為John Hunter,它也是一個開源專案,被同樣收錄進 NumFOCUS 組織維護的 Sponsored Project 裡。Jays-PySPEECH使用的是Matplotlib 2.2.3。
Matplotlib庫的官方主頁如下:
- Matplotlib官方主頁: https://matplotlib.org/
- Matplotlib安裝方法: https://pypi.org/project/matplotlib/
Matplotlib繪圖功能非常強大,但是作為一般使用,我們沒有必要去通讀其官方文件,其提供了非常多的example程式碼,這些example都在 https://matplotlib.org/gallery/index.html, 我們只要找到能滿足我們需求的example,在其基礎上簡單修改即可。 下面就是一個最簡單的正弦波示例:
import matplotlib
import matplotlib.pyplot as plt
import numpy as np
# Data for plotting
t = np.arange(0.0, 2.0, 0.01)
s = 1 + np.sin(2 * np.pi * t)
fig, ax = plt.subplots()
ax.plot(t, s)
ax.set(xlabel='time (s)', ylabel='voltage (mV)',
title='About as simple as it gets, folks')
ax.grid()
fig.savefig("test.png")
plt.show()
二、Jays-PySPEECH音訊顯示實現
Jays-PySPEECH關於音訊顯示功能實現主要有四點:選擇.wav檔案、讀取.wav檔案、繪製.wav波形、新增游標功能,最終Jays-PySPEECH效果如下圖所示,痞子衡為逐一為大家介紹實現細節。
2.1 選擇.wav檔案功能
選擇wav檔案主要藉助的是wxPython裡的genericDirCtrl控制元件提供的功能實現的,我們使用genericDirCtrl控制元件建立了一個名為m_genericDirCtrl_audioDir的物件,藉助其SetFilter()方法實現了僅顯示.wav檔案格式的過濾,並且我們為m_genericDirCtrl_audioDir還建立了一個event,即viewAudio(),這個event的觸發條件是選中m_genericDirCtrl_audioDir裡列出的.wav檔案,當viewAudio()被觸發時,我們通過GetFilePath()方法即可獲得選中的.wav檔案路徑。
class mainWin(win.speech_win):
def __init__(self, parent):
win.speech_win.__init__(self, parent)
# ...
self.m_genericDirCtrl_audioDir.SetFilter("Audio files (*.wav)|*.wav")
def viewAudio( self, event ):
self.wavPath = self.m_genericDirCtrl_audioDir.GetFilePath()
2.2 讀取.wav檔案功能
讀取.wav檔案主要藉助的是python自帶的標準庫wave,以及第三方的NumPy庫。痞子衡建立了一個名為wavCanvasPanel的類,在這個類中定義了readWave(self, wavPath, wavInfo)方法,其中引數wavPath即是要讀取的.wav檔案路徑,引數wavInfo是GUI狀態列物件,用於直觀顯示讀取到的.wav檔案資訊。
在wavCanvasPanel.readWave()方法中,痞子衡首先使用了wave庫裡的功能獲取到.wav檔案的所有資訊以及所有PCM資料,然後藉助NumPy庫將PCM資料按channel重新組織,便於後續圖形顯示。關於資料重新組織,有一個地方需要特別說明,即int24型別(3-byte)是不被NumPy中的fromstring()原生支援,因此痞子衡自己實現了一個非標準型別資料的fromstring()。
import numpy
import wave
class wavCanvasPanel(wx.Panel):
def fromstring(self, wavData, alignedByte):
if alignedByte <= 8:
src = numpy.ndarray(len(wavData), numpy.dtype('>i1'), wavData)
dest = numpy.zeros(len(wavData) / alignedByte, numpy.dtype('>i8'))
for i in range(alignedByte):
dest.view(dtype='>i1')[alignedByte-1-i::8] = src.view(dtype='>i1')[i::alignedByte]
[hex(x) for x in dest]
return True, dest
else:
return False, wavData
def readWave(self, wavPath, wavInfo):
if os.path.isfile(wavPath):
# Open the wav file to get wave data and parameters
wavFile = wave.open(wavPath, "rb")
wavParams = wavFile.getparams()
wavChannels = wavParams[0]
wavSampwidth = wavParams[1]
wavFramerate = wavParams[2]
wavFrames = wavParams[3]
wavInfo.SetStatusText('Opened Audio Info = ' +
'Channels:' + str(wavChannels) +
', SampWidth:' + str(wavSampwidth) + 'Byte' +
', SampRate:' + str(wavFramerate) + 'kHz' +
', FormatTag:' + wavParams[4])
wavData = wavFile.readframes(wavFrames)
wavFile.close()
# Transpose the wav data if wave has multiple channels
if wavSampwidth == 1:
dtype = numpy.int8
elif wavSampwidth == 2:
dtype = numpy.int16
elif wavSampwidth == 3:
dtype = None
elif wavSampwidth == 4:
dtype = numpy.float32
else:
return 0, 0, 0
if dtype != None:
retData = numpy.fromstring(wavData, dtype = dtype)
else:
# Implement int24 manually
status, retData = self.fromstring(wavData, 3)
if not status:
return 0, 0, 0
if wavChannels != 1:
retData.shape = -1, wavChannels
retData = retData.T
# Calculate and arange wave time
retTime = numpy.arange(0, wavFrames) * (1.0 / wavFramerate)
retChannels = wavChannels
return retChannels, retData, retTime
else:
return 0, 0, 0
2.3 繪製.wav波形功能
繪製.wav波形是最主要的功能。痞子衡在wavCanvasPanel類中實現了showWave(self, wavPath, wavInfo)方法,這個方法會在GUI控制元件m_genericDirCtrl_audioDir的事件函式viewAudio()中被呼叫。
在wavCanvasPanel.showWave()方法中,痞子衡首先使用了readWave()獲取.wav檔案中經過重新組織的PCM資料,然後藉助Matplotlib中的figure類中的add_axes()方法逐一將各channel的PCM資料繪製出來,並輔以各種資訊(x、y軸精度、標籤等)一同顯示出來。由於GUI控制元件裡專門用於顯示波形的Panel物件尺寸為720*360 inch,痞子衡限制了最多顯示.wav的前8通道。
import matplotlib
from matplotlib.backends.backend_wxagg import FigureCanvasWxAgg as FigureCanvas
from matplotlib.figure import Figure
MAX_AUDIO_CHANNEL = 8
#unit: inch
PLOT_PANEL_WIDTH = 720
PLOT_PANEL_HEIGHT = 360
#unit: percent
PLOT_AXES_WIDTH_TITLE = 0.05
PLOT_AXES_HEIGHT_LABEL = 0.075
class wavCanvasPanel(wx.Panel):
def __init__(self, parent):
wx.Panel.__init__(self, parent)
dpi = 60
width = PLOT_PANEL_WIDTH / dpi
height = PLOT_PANEL_HEIGHT / dpi
self.wavFigure = Figure(figsize=[width,height], dpi=dpi, facecolor='#404040')
self.wavCanvas = FigureCanvas(self, -1, self.wavFigure)
self.wavSizer = wx.BoxSizer(wx.VERTICAL)
self.wavSizer.Add(self.wavCanvas, 1, wx.EXPAND|wx.ALL)
self.SetSizerAndFit(self.wavSizer)
self.wavAxes = [None] * MAX_AUDIO_CHANNEL
def readWave(self, wavPath, wavInfo):
# ...
def showWave(self, wavPath, wavInfo):
self.wavFigure.clear()
waveChannels, waveData, waveTime = self.readWave(wavPath, wavInfo)
if waveChannels != 0:
# Note: only show max supported channel if actual channel > max supported channel
if waveChannels > MAX_AUDIO_CHANNEL:
waveChannels = MAX_AUDIO_CHANNEL
# Polt the waveform of each channel in sequence
for i in range(waveChannels):
left = PLOT_AXES_HEIGHT_LABEL
bottom = (1.0 / waveChannels) * (waveChannels - 1 - i) + PLOT_AXES_HEIGHT_LABEL
height = 1.0 / waveChannels - (PLOT_AXES_WIDTH_TITLE + PLOT_AXES_HEIGHT_LABEL)
width = 1 - left - 0.05
self.wavAxes[i] = self.wavFigure.add_axes([left, bottom, width, height], facecolor='k')
self.wavAxes[i].set_prop_cycle(color='#00F279', lw=[1])
self.wavAxes[i].set_xlabel('time (s)', color='w')
self.wavAxes[i].set_ylabel('value', color='w')
if waveChannels == 1:
data = waveData
else:
data = waveData[i]
self.wavAxes[i].plot(waveTime, data)
self.wavAxes[i].grid()
self.wavAxes[i].tick_params(labelcolor='w')
self.wavAxes[i].set_title('Audio Channel ' + str(i), color='w')
# Note!!!: draw() must be called if figure has been cleared once
self.wavCanvas.draw()
class mainWin(win.speech_win):
def __init__(self, parent):
win.speech_win.__init__(self, parent)
self.wavPanel = wavCanvasPanel(self.m_panel_plot)
# ...
def viewAudio( self, event ):
self.wavPath = self.m_genericDirCtrl_audioDir.GetFilePath()
self.wavPanel.showWave(self.wavPath, self.statusBar)
2.4 新增游標功能
游標定位功能不是必要功能,但其可以讓軟體看起來高大上,痞子衡建立了一個名為wavCursor類來實現它,主要在這個類中實現了moveMouse方法,這個方法將會被FigureCanvasWxAgg類中的mpl_connect()方法新增到各通道axes中。
MAX_AUDIO_CHANNEL = 8
class wavCursor(object):
def __init__(self, ax, x, y):
self.ax = ax
self.vline = ax.axvline(color='r', alpha=1)
self.hline = ax.axhline(color='r', alpha=1)
self.marker, = ax.plot([0],[0], marker="o", color="crimson", zorder=3)
self.x = x
self.y = y
self.xlim = self.x[len(self.x)-1]
self.text = ax.text(0.7, 0.9, '', bbox=dict(facecolor='red', alpha=0.5))
def moveMouse(self, event):
if not event.inaxes:
return
x, y = event.xdata, event.ydata
if x > self.xlim:
x = self.xlim
index = numpy.searchsorted(self.x, [x])[0]
x = self.x[index]
y = self.y[index]
self.vline.set_xdata(x)
self.hline.set_ydata(y)
self.marker.set_data([x],[y])
self.text.set_text('x=%1.2f, y=%1.2f' % (x, y))
self.text.set_position((x,y))
self.ax.figure.canvas.draw_idle()
class wavCanvasPanel(wx.Panel):
def __init__(self, parent):
# ...
self.wavAxes = [None] * MAX_AUDIO_CHANNEL
# 定義游標物件
self.wavCursor = [None] * MAX_AUDIO_CHANNEL
def showWave(self, wavPath, wavInfo):
# ...
if waveChannels != 0:
# ...
for i in range(waveChannels):
# ...
self.wavAxes[i].set_title('Audio Channel ' + str(i), color='w')
# 例項化游標物件,並使用mpl_connect()將moveMouse()動作加入游標物件
self.wavCursor[i] = wavCursor(self.wavAxes[i], waveTime, data)
self.wavCanvas.mpl_connect('motion_notify_event', self.wavCursor[i].moveMouse)
# ...
至此,語音處理工具Jays-PySPEECH誕生之音訊顯示實現痞子衡便介紹完畢了,掌聲在哪裡~~~