user3517: I've been trying to encode a video trailer for mobile Safari playback (iPhone). Using Handbrake for Windows, I selected the source .mov file and chose the iPhone 4 preset. I then checked off the Web optimized option and started the process. 
The resulting video did not play on my iPhone's Safari browser, however.
http://mobilevideo.jt.citeeze.com/static/trailer.mp4
For reference, here is the original file:
http://mobilevideo.jt.citeeze.com/static/53159_high.mov
Thanks!

user2178: Based on the link given in this answer on stackoverflow I will try to explain how to encode a video in an iPhone friendly format. 
The steps below are carried out on a Mac, but the windows version of Handbrake should be similar.

Open Handbrake.
Go to File -> Open Source and browse to your video.
Choose MP4 File as container. 
Input the settings shown below for the respective tabs:


Picture tab:
Keep aspect ratio - check
  Width - 480 (set to 960 if encoding for the iPhone 4)
  Anamorphic - None
  Cropping - Automatic  
Video tab:
Codec - H.264
  Video quality - RF = 21
  Constant framerate - 30  
Audio tab:
Codec - AAC
  Bitrate - 128
  Sample rate - 44.1
Advanced tab:
Add the following text in the textbox labeled Current x264 Advanced Options String: if you're encoding for a pre iPhone 4 device:
cabac=0:ref=2:me=umh:bframes=0:weightp=0:subq=6:trellis=0:8x8dct=0:level=3 
If it's an iPhone 4 or higher the text should be:
level=4.1

The Advanced tab should look like this (for the iPhone 3 encode):

Here's a MediaFire link to the converted video for iPhones before the 4:
http://www.mediafire.com/?tlyzcg1hyygq8zf

3517: <p>I've been trying to encode a video trailer for mobile Safari playback (iPhone). Using Handbrake for Windows, I selected the source .mov file and chose the iPhone 4 preset. I then checked off the Web optimized option and started the process. </p>

<p>The resulting video did not play on my iPhone's Safari browser, however.</p>

<p><a href="http://mobilevideo.jt.citeeze.com/static/trailer.mp4" rel="nofollow">http://mobilevideo.jt.citeeze.com/static/trailer.mp4</a></p>

<p>For reference, here is the original file:</p>

<p><a href="http://mobilevideo.jt.citeeze.com/static/53159_high.mov" rel="nofollow">http://mobilevideo.jt.citeeze.com/static/53159_high.mov</a></p>

<p>Thanks!</p>
 2178: <p>Based on the <a href="http://blog.zencoder.com/2010/09/30/how-to-encode-video-for-mobile-use/" rel="nofollow noreferrer">link</a> given in <a href="https://stackoverflow.com/a/5871802">this</a> answer on stackoverflow I will try to explain how to encode a video in an iPhone friendly format. </p>

<p>The steps below are carried out on a Mac, but the windows version of Handbrake should be similar.</p>

<ol>
<li>Open Handbrake.</li>
<li>Go to <code>File -&gt; Open Source</code> and browse to your video.</li>
<li>Choose <code>MP4 File</code> as container. </li>
<li>Input the settings shown below for the respective tabs:</li>
</ol>

<blockquote>
  <p><strong>Picture tab</strong>:</p>
  
  <p>Keep aspect ratio - check<br>
  Width - 480 (set to 960 if encoding for the iPhone 4)<br>
  Anamorphic - None<br>
  Cropping - Automatic  </p>
  
  <p><strong>Video tab</strong>:</p>
  
  <p>Codec - H.264<br>
  Video quality - RF = 21<br>
  Constant framerate - 30  </p>
  
  <p><strong>Audio tab</strong>:</p>
  
  <p>Codec - AAC<br>
  Bitrate - 128<br>
  Sample rate - 44.1</p>
  
  <p><strong>Advanced tab</strong>:</p>
  
  <p>Add the following text in the textbox labeled <code>Current x264 Advanced Options String:</code> if you're encoding for a pre iPhone 4 device:</p>
  
  <p><code>cabac=0:ref=2:me=umh:bframes=0:weightp=0:subq=6:trellis=0:8x8dct=0:level=3</code>  </p>
  
  <p>If it's an iPhone 4 or higher the text should be:</p>
  
  <p><code>level=4.1</code></p>
</blockquote>

<p>The Advanced tab should look like this (for the iPhone 3 encode):
<img src="https://i.stack.imgur.com/hpuiK.png" alt="enter image description here"></p>

<p>Here's a MediaFire link to the converted video for iPhones before the 4:</p>

<p><a href="http://www.mediafire.com/?tlyzcg1hyygq8zf" rel="nofollow noreferrer">http://www.mediafire.com/?tlyzcg1hyygq8zf</a></p>
