{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "import math\n",
    "import wave\n",
    "import sys\n",
    "import struct\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "ename": "ValueError",
     "evalue": "invalid literal for int() with base 10: '/run/user/1000/jupyter/kernel-6454a929-4509-4b51-949d-f1c910f7ce09.json'",
     "output_type": "error",
     "traceback": [
      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[0;31mValueError\u001b[0m                                Traceback (most recent call last)",
      "\u001b[0;32m<ipython-input-3-cc8beb2556b6>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[1;32m      3\u001b[0m \u001b[0msample_rate\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0mfp\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mgetframerate\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m      4\u001b[0m \u001b[0mtotal_num_samps\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0mfp\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mgetnframes\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 5\u001b[0;31m \u001b[0mfft_length\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0mint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0msys\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0margv\u001b[0m\u001b[0;34m[\u001b[0m\u001b[0;36m2\u001b[0m\u001b[0;34m]\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m\u001b[1;32m      6\u001b[0m \u001b[0mnum_fft\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0;34m(\u001b[0m\u001b[0mtotal_num_samps\u001b[0m \u001b[0;34m/\u001b[0m \u001b[0mfft_length\u001b[0m \u001b[0;34m)\u001b[0m \u001b[0;34m-\u001b[0m \u001b[0;36m2\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
      "\u001b[0;31mValueError\u001b[0m: invalid literal for int() with base 10: '/run/user/1000/jupyter/kernel-6454a929-4509-4b51-949d-f1c910f7ce09.json'"
     ]
    }
   ],
   "source": [
    "# 웨이브 파일을 열어라\n",
    "fp = wave.open('birdsound.wav',\"rb\")\n",
    "sample_rate = fp.getframerate()\n",
    "total_num_samps = fp.getnframes()\n",
    "fft_length = int(sys.argv[2])\n",
    "num_fft = (total_num_samps / fft_length ) - 2"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# 임시로 사용할 작업 배열을 만들어라\n",
    "temp = zeros((num_fft,fft_length),Float)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# 파일로부터 데이터를 읽어 들여라\n",
    "for i in range(num_fft):\n",
    "    tempb = fp.readframes(fft_length);\n",
    "    temp[i,:] = array(struct.unpack(\"%dB\"%(fft_length), \\\n",
    "                tempb),Float) - 128.0\n",
    "fp.close()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# 데이터를 창틀화하라\n",
    "temp = temp * hamming(fft_length)\n",
    "\n",
    "# FFT를 사용하여 변환하라, 파워를 반환하라\n",
    "freq_pwr  = 10*log10(1e-20+abs(real_fft(temp,fft_length))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# 결과를 도표하라\n",
    "n_out_pts = (fft_length / 2) + 1\n",
    "y_axis = 0.5*float(sample_rate) / n_out_pts * \\\n",
    "         arange(n_out_pts)\n",
    "x_axis = (total_num_samps / float(sample_rate)) / \\\n",
    "         num_fft * arange(num_fft)\n",
    "setvar(\"X\",\"Time (sec)\")\n",
    "setvar(\"Y\",\"Frequency (Hertz)\")\n",
    "conshade(freq_pwr,x_axis,y_axis)\n",
    "disfin()"
   ]
  }
 ],
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