[html] How do I embed a mp4 movie into my html?

You should look into Video For Everyone:

Video for Everybody is very simply a chunk of HTML code that embeds a video into a website using the HTML5 element which offers native playback in Firefox 3.5 and Safari 3 & 4 and an increasing number of other browsers.

The video is played by the browser itself. It loads quickly and doesn’t threaten to crash your browser.

In other browsers that do not support , it falls back to QuickTime.

If QuickTime is not installed, Adobe Flash is used. You can host locally or embed any Flash file, such as a YouTube video.

The only downside, is that you have to have 2/3 versions of the same video stored, but you can serve to every existing device/browser that supports video (i.e.: the iPhone).

<video width="640" height="360" poster="__POSTER__.jpg" controls="controls">
    <source src="__VIDEO__.mp4" type="video/mp4" />
    <source src="__VIDEO__.webm" type="video/webm" />
    <source src="__VIDEO__.ogv" type="video/ogg" /><!--[if gt IE 6]>
    <object width="640" height="375" classid="clsid:02BF25D5-8C17-4B23-BC80-D3488ABDDC6B"><!
    [endif]--><!--[if !IE]><!-->
    <object width="640" height="375" type="video/quicktime" data="__VIDEO__.mp4"><!--<![endif]-->
    <param name="src" value="__VIDEO__.mp4" />
    <param name="autoplay" value="false" />
    <param name="showlogo" value="false" />
    <object width="640" height="380" type="application/x-shockwave-flash"
        data="__FLASH__.swf?image=__POSTER__.jpg&amp;file=__VIDEO__.mp4">
        <param name="movie" value="__FLASH__.swf?image=__POSTER__.jpg&amp;file=__VIDEO__.mp4" />
        <img src="__POSTER__.jpg" width="640" height="360" />
        <p>
            <strong>No video playback capabilities detected.</strong>
            Why not try to download the file instead?<br />
            <a href="__VIDEO__.mp4">MPEG4 / H.264 “.mp4” (Windows / Mac)</a> |
            <a href="__VIDEO__.ogv">Ogg Theora &amp; Vorbis “.ogv” (Linux)</a>
        </p>
    </object><!--[if gt IE 6]><!-->
    </object><!--<![endif]-->
</video>

There is an updated version that is a bit more readable:

<!-- "Video For Everybody" v0.4.1 by Kroc Camen of Camen Design <camendesign.com/code/video_for_everybody>
     =================================================================================================================== -->
<!-- first try HTML5 playback: if serving as XML, expand `controls` to `controls="controls"` and autoplay likewise       -->
<!-- warning: playback does not work on iPad/iPhone if you include the poster attribute! fixed in iOS4.0                 -->
<video width="640" height="360" controls preload="none">
    <!-- MP4 must be first for iPad! -->
    <source src="__VIDEO__.MP4" type="video/mp4" /><!-- WebKit video    -->
    <source src="__VIDEO__.webm" type="video/webm" /><!-- Chrome / Newest versions of Firefox and Opera -->
    <source src="__VIDEO__.OGV" type="video/ogg" /><!-- Firefox / Opera -->
    <!-- fallback to Flash: -->
    <object width="640" height="384" type="application/x-shockwave-flash" data="__FLASH__.SWF">
        <!-- Firefox uses the `data` attribute above, IE/Safari uses the param below -->
        <param name="movie" value="__FLASH__.SWF" />
        <param name="flashvars" value="image=__POSTER__.JPG&amp;file=__VIDEO__.MP4" />
        <!-- fallback image. note the title field below, put the title of the video there -->
        <img src="__VIDEO__.JPG" width="640" height="360" alt="__TITLE__"
             title="No video playback capabilities, please download the video below" />
    </object>
</video>
<!-- you *must* offer a download link as they may be able to play the file locally. customise this bit all you want -->
<p> <strong>Download Video:</strong>
    Closed Format:  <a href="__VIDEO__.MP4">"MP4"</a>
    Open Format:    <a href="__VIDEO__.OGV">"OGG"</a>
</p>