Embed youtube video in high quality (HD)

If you upload high Quality (HD) video yo YouTube, Youtube  will  have an option HD for your video. But when you embed your video, the default is not HD. You need to  add ?hd=1 on the end of the youtube url.
Example, default embed code:
 <object style="height: 500px; width: 100%"><param name="movie" value="http://www.youtube.com/v/_qJJPgz_aZ4"><param name="allowFullScreen" value="true"><param name="allowScriptAccess" value="always">
<embed src="http://www.youtube.com/v/_qJJPgz_aZ4" type="application/x-shockwave-flash" allowfullscreen="true" allowScriptAccess="always" width="100%" height="500"></object>

After adding ?hd=1 on the end of the youtube url
 <object style="height: 500px; width: 100%"><param name="movie" value="http://www.youtube.com/v/_qJJPgz_aZ4?hd=1"><param name="allowFullScreen" value="true"><param name="allowScriptAccess" value="always">
<embed src="http://www.youtube.com/v/_qJJPgz_aZ4?hd=1" type="application/x-shockwave-flash" allowfullscreen="true" allowScriptAccess="always" width="100%" height="500"></object>

You can see the video quality is quite difference.