FFmpeg + JWplayer + Mp4 fails

Question

Im using JWplayer HTML5 6.5.3609, and the newest FFmpeg. This is how I set it up:

jwplayer("flowplayer1").setup({
    file: '/mp4.file.place'
    width: '100%',
    height: '100%',
    autostart: true,
    stretching: 'exactfit',
    ratio: "100%",
    responsive: true,
    primary: 'html5'
});

this is a direct access, if I call the MP4 file directly, browser can play it. I create this MP4 from standalone images:

ffmpeg -f image2 -r 1 -i img%d.png x.mp4

and no joy. I even tried to add some codecs:

-vcodec libx264 -acodec libfaac

still not work, I got this:

error loading media: file could not be played

the joke is, I tried it with FLV and it did worked... VLC player can play the MP4 file too

Answer 1

okay, thanks for the helps ( :) ) in the meantime I figured it out, I simply had to ad the

-pix_fmt yuv420p

parameter.