there are several approaches on how to do this - from real simple to more complex. here's a few sugestions:
1) since your video player should by default show the first frame of the video, just make sure the first frame is not black. you can either:
remove the fade-in from black and just start the vid at full alpha
place an image in the very first frame, directly before the fade in, then have your fade-in from black start on frame 2
have your image on the first frame, and then fade to black or cross fade to your video starting
2) export 1 frame of the video , or use another image, logo, etc , to use as your 'poster frame'. turn it into a movieclip symbol. then use action script to use that movieclip ( which is layered on top of the video player) to act as the button to begin the video. use a tween to fade out the button, and it will seem like a video cross-fade
3) use javascript and css on the web page ( in conjunction with actionscript) to accomplish your desired effect
there are many other ways too. if i can't use #1, then i prefer #2, as it affords me the most flexibility to acheive whatever effect i want.
with a movieclip symbol named 'poster' placed over a videoplayer named 'flvPlayer', this code would make it work. also shown is using
TweenLite for the fade out of 'poster'
poster.addEventListener(MouseEvent.CLICK, startVideo);
function startVideo(e:MouseEvent):void {
TweenLite.to(poster, 4,{alpha:0} );
flvPlayer.play();
} i hope that helps out with some ideas.