Cron Transcoding problems

Issue Summary

Here's what happens:

If I run cron.php in a browser window, it works fine. It transcodes one video from the queue

If I run cron from a cron job it fails.

I notice that at least two shell commands (4 or 5 sometimes) happen to transcode one video. It looks to me that when running via a cron job, only the first command (which i believe generates the thumbnail image) completes. I'm using wget with the following command line:

wget -O - -q -t 1 http://mydomain.com/cron.php > /dev/null

Question: Is there something about wget (or these commandline options) that would make it terminate prematurely after the first command returns its return value? I haven't tried curl or lynx methods yet to see if they work any better, but that's my next step and I'll report back if successful. Thanks!