recuerda que las varibles en PHP siempre llevan de prefijo el $ (dolar)
Código PHP:
<script>
var embed="";
embed= embed + '<object id="live_embed_player_flash" bgcolor="#000000" data="http://www-cdn.justin.tv/widgets/live_embed_player.swf?channel=<?php echo $channel; ?>"id="jtv_player_flash" type="application/x-shockwave-flash" style="visibility: visible;" height="100%" width="100%">';
embed= embed + '<param value="true" name="allowFullScreen" />';
embed= embed + '<param value="http://www-cdn.justin.tv/widgets/live_embed_player.swf" name="movie" />';
embed= embed + '<param value="channel=<?php echo $channel; ?>&publisherGuard=&publisherGuard=&auto_play=true&start_volume=25&hide_chat=true&backgroundImageUrl=http://s.justin.tv/jtv_user_pictures/competitiveonline-320x240-4.jpg&hostname=www.justin.tv&publisherTimezoneOffset=240&force_adotube=true&consumer_key=FiJpJu0rK7WDAFDDTvZ3g&auto_play=true&amp;consumer_key=FiJpJu0rK7WDAFDDTvZ3g&auto_play=true&start_volume=25" name="flashvars" />';
embed= embed + '<param value="transparent" name="wmode" name="allowscriptaccess" name="enablejsurls"name="enablehref" name="allownetworking" />';
embed= embed + '</object>';
document.write(embed);
</script>