Song thumbnails - take sections from the beginning, middle, and end of songs, and combine them into a discography-spanning summary of an artist's work.

song_thumnails.ipynb

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   "source": [
    "from pydub import AudioSegment as AS\n",
    "import numpy as np\n",
    "import toolz as tz\n",
    "import os"
   ]
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   "cell_type": "code",
   "execution_count": 2,
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    "def list_song_files(directory, file_extension = '.wma'):\n",
    "    \"\"\" ---------------------\n",
    "        String -> String-> List String\n",
    "        ---------------------\n",
    "        Recursively list full path of every song \n",
    "        with given file extension in directory. \n",
    "    \"\"\"\n",
    "    def get_files((directory, folder, files)):\n",
    "        return [os.path.join(directory,f) for f in files if f.endswith('.wma')]\n",
    "    \n",
    "    return tz.thread_last(\n",
    "        directory,\n",
    "        os.walk,\n",
    "        (tz.mapcat, get_files),\n",
    "        list)\n",
    "\n",
    "def get_song_parts(song):\n",
    "    \"\"\" ---------------------------------\n",
    "        AudioSegment -> List AudioSegment\n",
    "        ---------------------------------\n",
    "        Given segment, return short segment from \n",
    "        beginning, middle, and end of song. \n",
    "    \"\"\"\n",
    "    t = 12000 # 12 seconds\n",
    "    halfway = len(song) / 2\n",
    "    start = song[:t]\n",
    "    middle = song[halfway:halfway + t]\n",
    "    ending_offset = 5000 # helps avoid last few seconds, which are often silence\n",
    "    end = song[-(t + ending_offset):-ending_offset]\n",
    "    return [start, middle, end]\n",
    "\n",
    "def crossfade_join(segments, seconds = 1.5):\n",
    "    \"\"\" ------------------------------------------\n",
    "        List AudioSegment -> Float -> AudioSegment\n",
    "        ------------------------------------------\n",
    "        Concatenate segments while fading one smoothly into the next. \n",
    "    \"\"\"\n",
    "    return reduce(lambda x, y: x.append(y, crossfade = seconds * 1000), segments)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
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   "outputs": [],
   "source": [
    "directory = \"/home/bioage/projects/music/Music/Rush\"\n",
    "song_files = list_song_files(directory)\n",
    "np.random.shuffle(song_files) # Just wanted to mix things up"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "songs = map(AS.from_file, song_files)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "merged = crossfade_join(tz.mapcat(get_song_parts, songs))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "save_file = merged.export('test3.mp3', format = 'mp3')"
   ]
  }
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