How to draw waveform from waveformdata object in iOS Swift? - ios

Question

[
{
"id": "48250",
"created_at": "2014-07-06 13:05:10",
"user_id": "7",
"duration": "7376",
"permalink": "shawne-back-to-the-roots-2-05072014",
"description": "Years: 2000 - 2005\r\nSet Time: Warm Up (11 pm - 01 am)\r\n",
"downloadable": "1",
"genre": "Drum & Bass",
"genre_slush": "drumandbass",
"title": "Shawne # Back To The Roots 2 (05.07.2014)",
"uri": "https:\/\/api-v2.hearthis.at\/\/shawne-back-to-the-roots-2-05072014\/",
"permalink_url": "http:\/\/hearthis.at\/\/shawne-back-to-the-roots-2-05072014\/",
"artwork_url": "http:\/\/hearthis.at\/_\/cache\/images\/track\/500\/801982cafc20a06ccf6203f21f10c08d_w500.png",
"background_url": "",
"waveform_data": "http:\/\/hearthis.at\/_\/wave_data\/7\/3000_4382f398c454c47cf171aab674cf00f0.mp3.js",
"waveform_url": "http:\/\/hearthis.at\/_\/wave_image\/7\/4382f398c454c47cf171aab674cf00f0.mp3.png",
"user": {
"id": "7",
"permalink": "shawne",
"username": "Shawne (hearthis.at)",
"uri": "https:\/\/api-v2.hearthis.at\/shawne\/",
"permalink_url": "http:\/\/hearthis.at\/shawne\/",
"avatar_url": "http:\/\/hearthis.at\/_\/cache\/images\/user\/512\/06a8299b0e7d8f2909a22697badd7c09_w512.jpg"
},
"stream_url": "http:\/\/hearthis.at\/shawne\/shawne-back-to-the-roots-2-05072014\/listen\/",
"download_url": "http:\/\/hearthis.at\/shawne\/shawne-back-to-the-roots-2-05072014\/download\/",
"playback_count": "75",
"download_count": "9",
"favoritings_count": "7",
"favorited": false,
"comment_count": "0"
}
]
This Api returns waveform url and waveformdata. How do I convert waveform data to draw waveform similar to image in waveformurl
Api - https://hearthis.at/api-v2/

Answer 1

It looks like the "data" is merely a succession of bar heights:
[136,132,133,133,138,...]
So just draw a succession of bars at those heights (or heights proportional to them). You might need to draw just every nth bar, or maybe average each clump of n bars together, in order to get a neater representation (that is what they do at the site you pointed to).