[rmax] 2007-09-25

This is my first Q&D take on a viewer for the MJPEG stream from the conference.
It doesn't do any more than receiving the stream and displaying the images.
Ideas for improvement are:

   * allow switching between the two servers
   * reconnect (after a random backoff time) when the stream breaks down
   * save the images (either all or selected ones on a button click)
   * keep a history of the last N images so that the user can go back

Feel free to overwrite the code with improved versions, but please
add a short log entry to this page that says what you changed.

----

 package require Tk
 package require img::jpeg

 image create photo foo -width 800 -height 600
 pack [label .l -image foo]

 proc READ {fd} {
    global state toread frame
    switch -- $state {
	response {
	    gets $fd line
	    puts "RESPONSE: $line"
	    if {$line ne "HTTP/1.0 200 OK"} exit
	    set state header
	}
	header {
	    gets $fd line
	    puts "HEADER: $line"
	    if {$line eq ""} {
		set state boundary
	    }
	}
	boundary {
	    gets $fd line
	    puts -nonewline stderr "."
	    if {$line eq "--myboundary"} {
		set state mime
	    }
	}
	mime {
	    gets $fd line
	    puts "MIME: $line"
	    regexp {Content-Length: ([[:digit:]]+)} $line -> toread
	    if {$line eq ""} {
		fconfigure $fd -translation binary
		set state data
	    }
	}
	data {
	    set n [expr { $toread > 1000 ? 1000 : $toread }]
	    set data [read $fd $n]
	    incr toread -[string length $data]
	    append frame $data
	    if {$toread == 0} {
		foo configure -data $frame
		set frame ""
		set state boundary
		fconfigure $fd -translation crlf
	    }
	}
    }
 }

 set fd [socket us.tclers.tk 80]
 fconfigure $fd -buffering full -translation crlf
 puts $fd "GET /video.mjpg HTTP/1.0"
 puts $fd ""
 flush $fd
 fileevent $fd readable [list READ $fd]

 set state response
 set frame ""

[RZ] changed order of statements because of runtime error (proc READ not found)
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[Category Multimedia]