title: How do you understand this line from H264 specifications
body: <p>In the H264 (mpeg4 part 10 AVC) specifications available <a href="http://www.itu.int/rec/recommendation.asp?lang=en&amp;parent=T-REC-H.264-201201-S" rel="nofollow">here</a>, we can read the following on page 59 (a little bit simplified for the clarity of the question on SO):</p>
  
  <pre><code>for(i8x8 = 0; i8x8 &lt; 4; i8x8++) 
    for(i4x4 = 0; i4x4 &lt; 4; i4x4++) 
       if(CodedBlockPatternLuma &amp; (1 &lt;&lt; i8x8))
         doSomething()
  </code></pre>
  
  <p>I am wondering how to interpret the content of the <code>if</code> statement. Looking at other implementations it seems that the test to be done is to check whether it's 0 or not. It seems to make more sense, otherwise the condition can only be evaluated to <code>true</code> when <code>i8x8</code> is <code>0</code>.  How do you understand that?</p>