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           <dl>
             <dt>ffmpeg</dt><dd>starts the command</dd>
             <dt>-i <i>input_file</i></dt><dd>path, name and extension of the input file</dd>
-            <dt>-vf idet</dt><dd>This calls the <a href="http://www.tate.org.uk/research/publications/sustaining-consistent-video-presentation">idet (detect video interlacing type) filter</a>.</dd>
+            <dt>-vf idet</dt><dd>This calls the  <a href="https://ffmpeg.org/ffmpeg-filters.html#idet">idet (detect video interlacing type) filter</a>.</dd>
             <dt>-f null</dt><dd>Video is decoded with the <code>null</code> muxer. This allows video decoding without creating an output file.</dd>
             <dt>-</dt><dd>FFmpeg syntax requires a specified output, and <code>-</code> is just a place holder. No file is actually created. </dd>
           </dl>