Audio processing in Python.ipynb

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 "metadata": {
  "name": "Audio processing in Python"
 },
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 "nbformat_minor": 0,
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   "cells": [
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "# Audio processing in Python\n",
      "\n",
      "we use the Package `PyAudio` and some standard libraries"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "import sys\n",
      "import time\n",
      "from pyaudio import PyAudio, paFloat32\n",
      "import numpy as np"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 1
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "# Initialize PyAudio\n",
      "pa = PyAudio()"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 2
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "# Get some information about the default audio hardware\n",
      "default_device = pa.get_default_input_device_info()\n",
      "fs = int(default_device['defaultSampleRate'])\n",
      "channels = default_device['maxInputChannels']"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 3
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "def easy_read(stream, num_samples, num_channels):\n",
      "    \"\"\" \n",
      "    Read samples from stream and convert them to a numpy array\n",
      "\n",
      "    stream       is the stream to read from\n",
      "    num_samples  is the number of samples to read\n",
      "    num_channels is the number of channels to read\n",
      "    \"\"\"\n",
      "    data = stream.read(num_samples)\n",
      "    data = np.fromstring(data, dtype=np.float32)\n",
      "    data = np.reshape(data, (len(data)/num_channels,num_channels)).T\n",
      "    return data"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 4
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "def rms(arr):\n",
      "    \"\"\" calculates the rms power of an array \"\"\"\n",
      "    return np.sqrt(np.mean(np.power(arr, 2)))\n",
      "\n",
      "def dB(power): \n",
      "    \"\"\" calculates the logarithmic dB value of a power \"\"\"\n",
      "    return 20*np.log10(power)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 5
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "# open an input stream using the default audio device\n",
      "print('Open Stream on %s' % default_device['name'])\n",
      "stream = pa.open(rate=fs,\n",
      "                 channels=channels,\n",
      "                 format=paFloat32,\n",
      "                 input=True)\n",
      "\n",
      "# run for three seconds\n",
      "t_start = time.time()\n",
      "while time.time()-t_start < 3:\n",
      "    # read some audio data from the sound card\n",
      "    data = easy_read(stream, int(fs/10), channels)\n",
      "    for i in range(channels):\n",
      "        print(' %5.2f' % dB(rms(data[i,:])), end='')\n",
      "    print(' dB FS')\n",
      "\n",
      "stream.stop_stream()\n",
      "stream.close()\n",
      "print('Stream Closed')"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "Open Stream on Built-in Microph\n",
        " -80.31"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " -80.31 dB FS\n",
        " -83.32"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " -83.32 dB FS\n",
        " -84.52"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " -84.52 dB FS\n",
        " -85.42"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " -85.42 dB FS\n",
        " -84.31"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " -84.31 dB FS\n",
        " -84.54"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " -84.54 dB FS\n",
        " -83.95"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " -83.95 dB FS\n",
        " -83.29"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " -83.29 dB FS\n",
        " -83.85"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " -83.85 dB FS\n",
        " -81.96"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " -81.96 dB FS\n",
        " -58.30"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " -58.30 dB FS\n",
        " -77.62"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " -77.62 dB FS\n",
        " -80.63"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " -80.63 dB FS\n",
        " -84.42"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " -84.42 dB FS\n",
        " -83.95"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " -83.95 dB FS\n",
        " -85.04"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " -85.04 dB FS\n",
        " -84.94"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " -84.94 dB FS\n",
        " -84.45"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " -84.45 dB FS\n",
        " -82.53"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " -82.53 dB FS\n",
        " -82.50"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " -82.50 dB FS\n",
        " -84.29"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " -84.29 dB FS\n",
        " -84.71"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " -84.71 dB FS\n",
        " -83.29"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " -83.29 dB FS\n",
        "Stream Closed"
       ]
      },
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "\n"
       ]
      }
     ],
     "prompt_number": 6
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [],
     "language": "python",
     "metadata": {},
     "outputs": []
    }
   ],
   "metadata": {}
  }
 ]
}

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