title: Two H.264 mp4 videos: One plays in Chrome, one doesn't
body: <p>I have two different videos, both (as far as I know) generally captured in the same manner, that I'm trying to play using an HTML5 video tag in Chrome. Both videos open and play perfectly in VLC, so I don't think there's any issue with a corrupted file, and both are mp4's with an H.264 format, using YUV color space. However, when I try to play one in Chrome (<code>Version 21.0.1180.89</code>) it gives me a grayed-out play button, while the other works perfectly. For reference, my OS is Ubuntu 10.10, although I've seen the same problem in newer versions of the OS. This is whether I'm loading the video into the HTML5 tag, or navigating directly to the URL where the video is being stored. I'm somewhat at a loss here, does anyone know what direction I should go to find what the significant differences are between the two videos?</p>
  <h3>Edit:</h3>
  <p>This one works: <a href="https://dl.dropbox.com/u/100841270/1_G101_20120914_0139PM_Course_101.mp4" rel="noreferrer">https://dl.dropbox.com/u/100841270/1_G101_20120914_0139PM_Course_101.mp4</a></p>
  <p>This one does not: <a href="https://dl.dropbox.com/u/100841270/1_G101_20120914_1156AM_Course_101.mp4" rel="noreferrer">https://dl.dropbox.com/u/100841270/1_G101_20120914_1156AM_Course_101.mp4</a></p>
  <h3>Update:</h3>
  <p>It appears to have nothing to do with OS, since I've seen the same problem in both Windows and Linux. Chrome 22 beta in Ubuntu didn't seem to work either.</p>