there is a bug in
<pre><code class="cpp">

bool TiffEncoder::writeLibTiff( const Mat& img, const vector<int>& /*params*/)
{
...
...
switch(channels)
{
...
case 4:
{
...
break; // <== fix, this line in missing in original code
}
...
}
</code></pre>


so when HAVE_TIFF enabled you can't save 4 channel tiff's :)