大家好,我是痞子衡,是正经搞技术的痞子。今天痞子衡给大家介绍的是语音处理工具Jays-PySPEECH诞生之音频显示实现。
音频显示是Jays-PySPEECH的主要功能,Jays-PySPEECH借助的是Matplotlib以及NumPy来实现的音频显示功能,今天痞子衡为大家介绍音频显示在Jays-PySPEECH中是如何实现的。
一、SciPy工具集
SciPy是一套Python科学计算相关的工具集,其本身也是一个Python库,这个工具集主要包含以下6大Python库,Jays-PySPEECH所用到的Matplotlib以及NumPy均属于SciPy工具集。
1.1 NumPy
NumPy是一套最基础的Python科学计算包,它主要用于数组与矩阵运算,它是一个开源项目,被收录进 NumFOCUS 组织维护的 Sponsored Project 里。Jays-PySPEECH使用的是NumPy 1.15.0。
NumPy库的官方主页如下:
NumPy官方主页: /NumPy安装方法: /project/numpy/
NumPy的快速上手可参考这个网页 /doc/numpy/user/quickstart.html
1.2 Matplotlib
Matplotlib是一套Python高质量2D绘图库,它的初始设计者为John Hunter,它也是一个开源项目,被同样收录进 NumFOCUS 组织维护的 Sponsored Project 里。Jays-PySPEECH使用的是Matplotlib 2.2.3。
Matplotlib库的官方主页如下:
Matplotlib官方主页: /Matplotlib安装方法: /project/matplotlib/
Matplotlib绘图功能非常强大,但是作为一般使用,我们没有必要去通读其官方文档,其提供了非常多的example代码,这些example都在 /gallery/index.html, 我们只要找到能满足我们需求的example,在其基础上简单修改即可。 下面就是一个最简单的正弦波示例:
import matplotlibimport matplotlib.pyplot as pltimport numpy as np# Data for plottingt = 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音频显示实现
Jays-PySPEECH关于音频显示功能实现主要有四点:选择.wav文件、读取.wav文件、绘制.wav波形、添加光标功能,最终Jays-PySPEECH效果如下图所示,痞子衡为逐一为大家介绍实现细节。
2.1 选择.wav文件功能
选择wav文件主要借助的是wxPython里的genericDirCtrl控件提供的功能实现的,我们使用genericDirCtrl控件创建了一个名为m_genericDirCtrl_audioDir的对象,借助其SetFilter()方法实现了仅显示.wav文件格式的过滤,并且我们为m_genericDirCtrl_audioDir还创建了一个event,即viewAudio(),这个event的触发条件是选中m_genericDirCtrl_audioDir里列出的.wav文件,当viewAudio()被触发时,我们通过GetFilePath()方法即可获得选中的.wav文件路径。
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 读取.wav文件功能
读取.wav文件主要借助的是python自带的标准库wave,以及第三方的NumPy库。痞子衡创建了一个名为wavCanvasPanel的类,在这个类中定义了readWave(self, wavPath, wavInfo)方法,其中参数wavPath即是要读取的.wav文件路径,参数wavInfo是GUI状态栏对象,用于直观显示读取到的.wav文件信息。
在wavCanvasPanel.readWave()方法中,痞子衡首先使用了wave库里的功能获取到.wav文件的所有信息以及所有PCM数据,然后借助NumPy库将PCM数据按channel重新组织,便于后续图形显示。关于数据重新组织,有一个地方需要特别说明,即int24类型(3-byte)是不被NumPy中的fromstring()原生支持,因此痞子衡自己实现了一个非标准类型数据的fromstring()。
import numpyimport waveclass 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, destelse:return False, wavDatadef readWave(self, wavPath, wavInfo):if os.path.isfile(wavPath):# Open the wav file to get wave data and parameterswavFile = 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 channelsif wavSampwidth == 1:dtype = numpy.int8elif wavSampwidth == 2:dtype = numpy.int16elif wavSampwidth == 3:dtype = Noneelif wavSampwidth == 4:dtype = numpy.float32else:return 0, 0, 0if dtype != None:retData = numpy.fromstring(wavData, dtype = dtype)else:# Implement int24 manuallystatus, retData = self.fromstring(wavData, 3)if not status:return 0, 0, 0if wavChannels != 1:retData.shape = -1, wavChannelsretData = retData.T# Calculate and arange wave timeretTime = numpy.arange(0, wavFrames) * (1.0 / wavFramerate)retChannels = wavChannelsreturn retChannels, retData, retTimeelse:return 0, 0, 0
2.3 绘制.wav波形功能
绘制.wav波形是最主要的功能。痞子衡在wavCanvasPanel类中实现了showWave(self, wavPath, wavInfo)方法,这个方法会在GUI控件m_genericDirCtrl_audioDir的事件函数viewAudio()中被调用。
在wavCanvasPanel.showWave()方法中,痞子衡首先使用了readWave()获取.wav文件中经过重新组织的PCM数据,然后借助Matplotlib中的figure类中的add_axes()方法逐一将各channel的PCM数据绘制出来,并辅以各种信息(x、y轴精度、标签等)一同显示出来。由于GUI控件里专门用于显示波形的Panel对象尺寸为720*360 inch,痞子衡限制了最多显示.wav的前8通道。
import matplotlibfrom matplotlib.backends.backend_wxagg import FigureCanvasWxAgg as FigureCanvasfrom matplotlib.figure import FigureMAX_AUDIO_CHANNEL = 8#unit: inchPLOT_PANEL_WIDTH = 720PLOT_PANEL_HEIGHT = 360#unit: percentPLOT_AXES_WIDTH_TITLE = 0.05PLOT_AXES_HEIGHT_LABEL = 0.075class wavCanvasPanel(wx.Panel):def __init__(self, parent):wx.Panel.__init__(self, parent)dpi = 60width = PLOT_PANEL_WIDTH / dpiheight = PLOT_PANEL_HEIGHT / dpiself.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_CHANNELdef 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 channelif waveChannels > MAX_AUDIO_CHANNEL:waveChannels = MAX_AUDIO_CHANNEL# Polt the waveform of each channel in sequencefor i in range(waveChannels):left = PLOT_AXES_HEIGHT_LABELbottom = (1.0 / waveChannels) * (waveChannels - 1 - i) + PLOT_AXES_HEIGHT_LABELheight = 1.0 / waveChannels - (PLOT_AXES_WIDTH_TITLE + PLOT_AXES_HEIGHT_LABEL)width = 1 - left - 0.05self.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 = waveDataelse: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 onceself.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 添加光标功能
光标定位功能不是必要功能,但其可以让软件看起来高大上,痞子衡创建了一个名为wavCursor类来实现它,主要在这个类中实现了moveMouse方法,这个方法将会被FigureCanvasWxAgg类中的mpl_connect()方法添加到各通道axes中。
MAX_AUDIO_CHANNEL = 8class wavCursor(object):def __init__(self, ax, x, y):self.ax = axself.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 = xself.y = yself.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:returnx, y = event.xdata, event.ydataif x > self.xlim:x = self.xlimindex = 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# 定义光标对象self.wavCursor = [None] * MAX_AUDIO_CHANNELdef showWave(self, wavPath, wavInfo):# ...if waveChannels != 0:# ...for i in range(waveChannels):# ...self.wavAxes[i].set_title('Audio Channel ' + str(i), color='w')# 实例化光标对象,并使用mpl_connect()将moveMouse()动作加入光标对象self.wavCursor[i] = wavCursor(self.wavAxes[i], waveTime, data)self.wavCanvas.mpl_connect('motion_notify_event', self.wavCursor[i].moveMouse)# ...
至此,语音处理工具Jays-PySPEECH诞生之音频显示实现痞子衡便介绍完毕了,掌声在哪里~~~
参考文档
Embedding a matplotlib figure inside a WxPython panel软妹子带你玩转Python数据可视化Axes绘图布局方法介绍