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     <body>
         <h1>Block video encoding test</h1>
 
+        <p>
+            Test work for a video encoding using Atari 800-family GTIA grayscale mode on top of text cells.
+            This allows a "block dictionary" of 128 2x8-pixel blocks on an 80x160 grayscale image,
+            at cost of 1840 bytes per full frame or 800 bytes to reuse previous blocks.
+        </p>
+
+        <p>
+            Currently just converts to grayscale and counts up unique blocks.
+            Next step: decimate if &gt; 128 unique blocks per image, and combine
+            the most similar blocks in the output.
+        </p>
+
         <h2>Source video</h2>
         <div>
             <video id="source" src="llamigos.webm" class="stretchy" muted controls playsinline></video>
