Video´s format for smooth playing

I am testing with several video files. I have an LCD and i want to show HD video in this.

I have a MP4 file, when i play it in windows media player, shows smooth, but when it reproduces in SignagePLayer the video looks a little slow, with a delay.

What video format do you recommends for HD reproduction in Signage Player? (MP4, FLV, MPG2, OGG, MKV), what size of video, (1920 x 1080, 1280 X 1024)?

I have a COre2Quad, 4 gb RAM, a Nvidia Gforce 9400 GT with HDMI OUTPUT Windows 7

PS Sorry about my english

We recommend usign FLV (Flash Video) with H.264 encoded

See this:
http://mediasignage.com/html/signage_video.html?videoNumber=VideoConversion


Regards,

Sean - MediaSignage.com