Just add this to the code generated by Google Video as an attribute of embed:
FlashVars="initialTime=2171"
The starting point is expressed in seconds, so you need to make a little conversion.
Another interesting value of FlashVars is:
FlashVars="autoPlay=true"
This way, the video starts after the page loads. This is not recommended, because a page may have more videos and users shouldn't be forced to watch your annoying video.
You can combine the values like this:
FlashVars="autoPlay=true&initialTime=2171"
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{ From Google Video Blog. }