title: SoundCloud API - genres and filter parameter of /tracks endpoint
body: <p>I am using the SoundCloud API for a web application.
  With the <strong>/tracks</strong> endpoint, I have two troubles below.</p>
  
  <h2>1. When I send a request with an invalid genres parameters, does the /tracks endpoint return 503 (Service Unavailable)?</h2>
  
  <p>When I intentionally use a condition which will not match any tracks <strong>with the q parameter</strong> like</p>
  
  <pre><code>http://api.soundcloud.com/tracks?q=ewkqtieorak&amp;client_id=MY_CLIENT_ID&amp;format=json&amp;_status_code_map%5B302%5D=200
  </code></pre>
  
  <p>, responses are empty array as I expect, but <strong>with the genres parameter</strong> like</p>
  
  <pre><code>http://api.soundcloud.com/tracks?genres=hoge&amp;client_id=MY_CLIENT_ID&amp;format=json&amp;_status_code_map%5B302%5D=200
  </code></pre>
  
  <p>, responses are always 503 (I tried about 500 times). </p>
  
  <p>The /tracks endpoint return status 503 so often even with existing genres that I am not sure it means there are not such genres or SoundCloud is having a server trouble. Are there any ways to distinguish them?</p>
  
  <hr>
  
  <h2>2. It seems that the filter parameter doesn't work correctly.</h2>
  
  <p>Example requests are below. I wanted streamable tracks and added "streamable" as a filter parameter, but response tracks include some unstreamable tracks. Am I using it incorrectly?</p>
  
  <pre><code>http://api.soundcloud.com/tracks?filter=streamable&amp;genres=electronica&amp;client_id=MY_CLIENT_ID&amp;format=json
  </code></pre>
  
  
  
  <pre><code>http://api.soundcloud.com/tracks?filter=streamable&amp;order=hotness&amp;genres=jazz%2Cclassical&amp;bpm[from]=0&amp;bpm[to]=100&amp;created_at[from]=2011-11-24%2000%3A00%3A00&amp;created_at[to]=2012-02-22%2000%3A00%3A00&amp;limit=5&amp;client_id=MY_CLIENT_ID&amp;format=json&amp;_status_code_map[302]=200
  </code></pre>
  
  
  
  <pre><code>http://api.soundcloud.com/tracks?filter=streamable&amp;order=hotness&amp;genres=jazz%2Cclassical&amp;bpm[from]=0&amp;bpm[to]=100&amp;created_at[from]=2012-01-03%2000%3A00%3A00&amp;created_at[to]=2012-04-02%2000%3A00%3A00&amp;limit=30&amp;client_id=MY_CLIENT_ID&amp;format=json&amp;_status_code_map[302]=200
  </code></pre>