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Commit 22d94ff4 authored by Leigh Smith's avatar Leigh Smith
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Added in spectral moments computation

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notebooks/spectral_features.ipynb
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...@@ -123,11 +123,33 @@ ...@@ -123,11 +123,33 @@
"source": [ "source": [
"When we feature extract a sample collection, we need to sequentially access audio files, segment them (or not), and feature extract them. Loading a lot of audio files into memory is not always a feasible or desirable operation, so you will create a loop which loads an audio file, feature extracts it, and closes the audio file. Note that the only information that we retain in memory are the features that are extracted.\n", "When we feature extract a sample collection, we need to sequentially access audio files, segment them (or not), and feature extract them. Loading a lot of audio files into memory is not always a feasible or desirable operation, so you will create a loop which loads an audio file, feature extracts it, and closes the audio file. Note that the only information that we retain in memory are the features that are extracted.\n",
"\n", "\n",
"Create a loop which reads in an audio file, extracts the zero crossing rate, and some spectral statistics. You can use the \"in\" operator to retrieve each audio file URL from process_corpus(), as used above. The feature information for each audio file (the \"feature vector\") should be stored as a feature array, with columns being the features and rows for each file. For example:\n", "Create a loop which reads in an audio file, extracts the zero crossing rate, and some spectral statistics. You can use the \"in\" operator to retrieve each audio file URL from process_corpus(), as used above. The feature information for each audio file (the \"feature vector\") should be stored as a feature array, with columns being the features and rows for each file. For example:"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import numpy as np\n",
"\n", "\n",
" featuresSnare =\n", "number_of_files = 20\n",
"number_of_features = 5\n",
"features_snare = np.zeros([number_of_files, number_of_features])"
],
"language": "python",
"metadata": {},
"outputs": [],
"prompt_number": 15
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
" For example, when populated, features_snare might look like:\n",
" \n",
" features_snare =\n",
"\n", "\n",
" 0.5730 1.9183 2.9713 0.0004 0.0002\n", " 0.5730 1.9183 2.9713 0.0004 0.0002\n",
" 0.4750 1.4834 2.4463 0.0004 0.0012\n", " 0.4750 1.4834 2.4463 0.0004 0.0012\n",
" 0.5900 2.2857 3.1788 0.0003 0.0041\n", " 0.5900 2.2857 3.1788 0.0003 0.0041\n",
" 0.5090 1.6622 2.6369 0.0004 0.0051\n", " 0.5090 1.6622 2.6369 0.0004 0.0051\n",
...@@ -154,36 +176,133 @@ ...@@ -154,36 +176,133 @@
], ],
"language": "python", "language": "python",
"metadata": {}, "metadata": {},
"outputs": [], "outputs": [
"prompt_number": 5 {
"ename": "IOError",
"evalue": "[Errno socket error] _ssl.c:320: Invalid SSL protocol variant specified.",
"output_type": "pyerr",
"traceback": [
"\u001b[0;31m---------------------------------------------------------------------------\u001b[0m\n\u001b[0;31mIOError\u001b[0m Traceback (most recent call last)",
"\u001b[0;32m<ipython-input-16-f4740563a986>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[1;32m 3\u001b[0m \u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 4\u001b[0m \u001b[0msample_rate\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0;36m44100\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 5\u001b[0;31m \u001b[0murllib\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0murlretrieve\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0msnare_URL\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mfilename\u001b[0m\u001b[0;34m=\u001b[0m\u001b[0;34m'/tmp/localfile.wav'\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m\u001b[1;32m 6\u001b[0m \u001b[0maudio\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0mMonoLoader\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mfilename\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0;34m'/tmp/localfile.wav'\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0msampleRate\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0msample_rate\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
"\u001b[0;32m/sw/lib/python2.7/urllib.pyc\u001b[0m in \u001b[0;36murlretrieve\u001b[0;34m(url, filename, reporthook, data)\u001b[0m\n\u001b[1;32m 92\u001b[0m \u001b[0;32mif\u001b[0m \u001b[0;32mnot\u001b[0m \u001b[0m_urlopener\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 93\u001b[0m \u001b[0m_urlopener\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0mFancyURLopener\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m---> 94\u001b[0;31m \u001b[0;32mreturn\u001b[0m \u001b[0m_urlopener\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mretrieve\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0murl\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mfilename\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mreporthook\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mdata\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m\u001b[1;32m 95\u001b[0m \u001b[0;32mdef\u001b[0m \u001b[0murlcleanup\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 96\u001b[0m \u001b[0;32mif\u001b[0m \u001b[0m_urlopener\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
"\u001b[0;32m/sw/lib/python2.7/urllib.pyc\u001b[0m in \u001b[0;36mretrieve\u001b[0;34m(self, url, filename, reporthook, data)\u001b[0m\n\u001b[1;32m 238\u001b[0m \u001b[0;32mexcept\u001b[0m \u001b[0mIOError\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 239\u001b[0m \u001b[0;32mpass\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m--> 240\u001b[0;31m \u001b[0mfp\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0mself\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mopen\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0murl\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mdata\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m\u001b[1;32m 241\u001b[0m \u001b[0;32mtry\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 242\u001b[0m \u001b[0mheaders\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0mfp\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0minfo\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
"\u001b[0;32m/sw/lib/python2.7/urllib.pyc\u001b[0m in \u001b[0;36mopen\u001b[0;34m(self, fullurl, data)\u001b[0m\n\u001b[1;32m 206\u001b[0m \u001b[0;32mtry\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 207\u001b[0m \u001b[0;32mif\u001b[0m \u001b[0mdata\u001b[0m \u001b[0;32mis\u001b[0m \u001b[0mNone\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m--> 208\u001b[0;31m \u001b[0;32mreturn\u001b[0m \u001b[0mgetattr\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mself\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mname\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0murl\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m\u001b[1;32m 209\u001b[0m \u001b[0;32melse\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 210\u001b[0m \u001b[0;32mreturn\u001b[0m \u001b[0mgetattr\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mself\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mname\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0murl\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mdata\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
"\u001b[0;32m/sw/lib/python2.7/urllib.pyc\u001b[0m in \u001b[0;36mopen_https\u001b[0;34m(self, url, data)\u001b[0m\n\u001b[1;32m 435\u001b[0m \u001b[0;32mif\u001b[0m \u001b[0mrealhost\u001b[0m\u001b[0;34m:\u001b[0m \u001b[0mh\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mputheader\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m'Host'\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mrealhost\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 436\u001b[0m \u001b[0;32mfor\u001b[0m \u001b[0margs\u001b[0m \u001b[0;32min\u001b[0m \u001b[0mself\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0maddheaders\u001b[0m\u001b[0;34m:\u001b[0m \u001b[0mh\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mputheader\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m*\u001b[0m\u001b[0margs\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m--> 437\u001b[0;31m \u001b[0mh\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mendheaders\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mdata\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m\u001b[1;32m 438\u001b[0m \u001b[0merrcode\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0merrmsg\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mheaders\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0mh\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mgetreply\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 439\u001b[0m \u001b[0mfp\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0mh\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mgetfile\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
"\u001b[0;32m/sw/lib/python2.7/httplib.pyc\u001b[0m in \u001b[0;36mendheaders\u001b[0;34m(self, message_body)\u001b[0m\n\u001b[1;32m 989\u001b[0m \u001b[0;32melse\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 990\u001b[0m \u001b[0;32mraise\u001b[0m \u001b[0mCannotSendHeader\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m--> 991\u001b[0;31m \u001b[0mself\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0m_send_output\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mmessage_body\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m\u001b[1;32m 992\u001b[0m \u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 993\u001b[0m \u001b[0;32mdef\u001b[0m \u001b[0mrequest\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mself\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mmethod\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0murl\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mbody\u001b[0m\u001b[0;34m=\u001b[0m\u001b[0mNone\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mheaders\u001b[0m\u001b[0;34m=\u001b[0m\u001b[0;34m{\u001b[0m\u001b[0;34m}\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
"\u001b[0;32m/sw/lib/python2.7/httplib.pyc\u001b[0m in \u001b[0;36m_send_output\u001b[0;34m(self, message_body)\u001b[0m\n\u001b[1;32m 842\u001b[0m \u001b[0mmsg\u001b[0m \u001b[0;34m+=\u001b[0m \u001b[0mmessage_body\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 843\u001b[0m \u001b[0mmessage_body\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0mNone\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m--> 844\u001b[0;31m \u001b[0mself\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0msend\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mmsg\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m\u001b[1;32m 845\u001b[0m \u001b[0;32mif\u001b[0m \u001b[0mmessage_body\u001b[0m \u001b[0;32mis\u001b[0m \u001b[0;32mnot\u001b[0m \u001b[0mNone\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 846\u001b[0m \u001b[0;31m#message_body was not a string (i.e. it is a file) and\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
"\u001b[0;32m/sw/lib/python2.7/httplib.pyc\u001b[0m in \u001b[0;36msend\u001b[0;34m(self, data)\u001b[0m\n\u001b[1;32m 804\u001b[0m \u001b[0;32mif\u001b[0m \u001b[0mself\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0msock\u001b[0m \u001b[0;32mis\u001b[0m \u001b[0mNone\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 805\u001b[0m \u001b[0;32mif\u001b[0m \u001b[0mself\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mauto_open\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m--> 806\u001b[0;31m \u001b[0mself\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mconnect\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 807\u001b[0m \u001b[0;32melse\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 808\u001b[0m \u001b[0;32mraise\u001b[0m \u001b[0mNotConnected\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
"\u001b[0;32m/sw/lib/python2.7/httplib.pyc\u001b[0m in \u001b[0;36mconnect\u001b[0;34m(self)\u001b[0m\n\u001b[1;32m 1196\u001b[0m \u001b[0mself\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0msock\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0msock\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 1197\u001b[0m \u001b[0mself\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0m_tunnel\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m-> 1198\u001b[0;31m \u001b[0mself\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0msock\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0mssl\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mwrap_socket\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0msock\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mself\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mkey_file\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mself\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mcert_file\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m\u001b[1;32m 1199\u001b[0m \u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 1200\u001b[0m \u001b[0m__all__\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mappend\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m\"HTTPSConnection\"\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
"\u001b[0;32m/sw/lib/python2.7/ssl.pyc\u001b[0m in \u001b[0;36mwrap_socket\u001b[0;34m(sock, keyfile, certfile, server_side, cert_reqs, ssl_version, ca_certs, do_handshake_on_connect, suppress_ragged_eofs, ciphers)\u001b[0m\n\u001b[1;32m 390\u001b[0m \u001b[0mdo_handshake_on_connect\u001b[0m\u001b[0;34m=\u001b[0m\u001b[0mdo_handshake_on_connect\u001b[0m\u001b[0;34m,\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 391\u001b[0m \u001b[0msuppress_ragged_eofs\u001b[0m\u001b[0;34m=\u001b[0m\u001b[0msuppress_ragged_eofs\u001b[0m\u001b[0;34m,\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m--> 392\u001b[0;31m ciphers=ciphers)\n\u001b[0m\u001b[1;32m 393\u001b[0m \u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 394\u001b[0m \u001b[0;34m\u001b[0m\u001b[0m\n",
"\u001b[0;32m/sw/lib/python2.7/ssl.pyc\u001b[0m in \u001b[0;36m__init__\u001b[0;34m(self, sock, keyfile, certfile, server_side, cert_reqs, ssl_version, ca_certs, do_handshake_on_connect, suppress_ragged_eofs, ciphers)\u001b[0m\n\u001b[1;32m 144\u001b[0m \u001b[0mkeyfile\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mcertfile\u001b[0m\u001b[0;34m,\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 145\u001b[0m \u001b[0mcert_reqs\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mssl_version\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mca_certs\u001b[0m\u001b[0;34m,\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m--> 146\u001b[0;31m ciphers)\n\u001b[0m\u001b[1;32m 147\u001b[0m \u001b[0;32mif\u001b[0m \u001b[0mdo_handshake_on_connect\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 148\u001b[0m \u001b[0mself\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mdo_handshake\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
"\u001b[0;31mIOError\u001b[0m: [Errno socket error] _ssl.c:320: Invalid SSL protocol variant specified."
]
}
],
"prompt_number": 16
}, },
{ {
"cell_type": "markdown", "cell_type": "markdown",
"metadata": {}, "metadata": {},
"source": [ "source": [
"Here's an example of how to feature extract the first frame from the current audio file..." "Here's an example of how to feature extract the first frame from the current audio file, using Essentia's [ZeroCrossingRate](http://essentia.upf.edu/documentation/reference/streaming_ZeroCrossingRate.html) and [CentralMoments](http://essentia.upf.edu/documentation/reference/std_CentralMoments.html) classes..."
] ]
}, },
{ {
"cell_type": "code", "cell_type": "code",
"collapsed": false, "collapsed": false,
"input": [ "input": [
" frameSize = 0.100 * sample_rate # 100ms\n", "from essentia.standard import ZeroCrossingRate, CentralMoments, Spectrum, Windowing\n",
" currentFrame = audio[0 : frameSize]\n", "zcr = ZeroCrossingRate()\n",
" # featuresSnare[i, 0] = zcr(currentFrame)\n", "hamming_window = Windowing(type = 'hamming') # we need to window the frame to avoid FFT artifacts.\n",
" # centroid, bandwidth, skew, kurtosis = spectralMoments(currentFrame, sample_rate, 8192)\n", "spectrum = Spectrum()\n",
" # featuresSnare[i, 1:4] = [centroid, bandwidth, skew, kurtosis]" "central_moments = CentralMoments()\n",
"\n",
"frame_size = 0.100 * sample_rate # 100ms\n",
"file_index = 0 # to process a single file, this will be your file loop iteration\n",
"\n",
"current_frame = audio[0 : frame_size]\n",
"features_snare[file_index, 0] = zcr(current_frame)\n",
"spectral_magnitude = spectrum(hamming_window(current_frame))\n",
"\n",
"# Normalize the spectral magnitude\n",
"norm_spectral_mag = spectral_magnitude / np.sum(spectral_magnitude);\n",
"# Make index vector\n",
"indices = np.arange(spectral_magnitude.shape[0])\n",
"\n",
"# Centroid, in spectral coefficient indices.\n",
"centroid = np.sum(norm_spectral_mag * indices)\n",
"centroid"
], ],
"language": "python", "language": "python",
"metadata": {}, "metadata": {},
"outputs": [], "outputs": [
"prompt_number": 14 {
"metadata": {},
"output_type": "pyout",
"prompt_number": 23,
"text": [
"485.13728477961195"
]
}
],
"prompt_number": 23
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Now we use the magnitude of the spectrum to compute a 5 element array, corresponding to:\n",
"# zeroth central moment (1.0)\n",
"# first central moment (Not the centroid, which is the first moment!)\n",
"# bandwidth\n",
"# skew\n",
"# kurtosis.\n",
"spectral_moments = central_moments(spectral_magnitude)\n",
"spectral_moments"
],
"language": "python",
"metadata": {},
"outputs": [
{
"metadata": {},
"output_type": "pyout",
"prompt_number": 32,
"text": [
"array([ 1. , 0. , 0.04079479, 0.00723291, 0.00497805], dtype=float32)"
]
}
],
"prompt_number": 32
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Remember the zeroth column of features_snare is the ZCR.\n",
"features_snare[file_index, 1] = centroid\n",
"features_snare[file_index, 2:5] = spectral_moments[2:5]\n",
"features_snare[file_index]"
],
"language": "python",
"metadata": {},
"outputs": [
{
"metadata": {},
"output_type": "pyout",
"prompt_number": 34,
"text": [
"array([ 1.29251704e-01, 4.85137285e+02, 4.07947935e-02,\n",
" 7.23291235e-03, 4.97804629e-03])"
]
}
],
"prompt_number": 34
}, },
{ {
"cell_type": "markdown", "cell_type": "markdown",
"metadata": {}, "metadata": {},
"source": [ "source": [
"4. First, extract all of the feature data for the kick drums and store it in a feature array. (For my example, above, I'd put it in \"featuresKick\")\n", "4. First, extract all of the feature data for the kick drums and store it in a feature array. (For my example, above, I'd put it in \"features_kick\")\n",
"\n", "\n",
"5. Next, extract all of the feature data for the snares, storing them in a different array. \n", "5. Next, extract all of the feature data for the snares, storing them in a different array. \n",
"Again, the kick and snare features should be separated in two different arrays!\n", "Again, the kick and snare features should be separated in two different arrays!\n",
......
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